Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time.
An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.
Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.
Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.
A class of statistical procedures for estimating the survival function (function of time, starting with a population 100% well at a given time and providing the percentage of the population still well at later times). The survival analysis is then used for making inferences about the effects of treatments, prognostic factors, exposures, and other covariates on the function.
A nonparametric method of compiling LIFE TABLES or survival tables. It combines calculated probabilities of survival and estimates to allow for observations occurring beyond a measurement threshold, which are assumed to occur randomly. Time intervals are defined as ending each time an event occurs and are therefore unequal. (From Last, A Dictionary of Epidemiology, 1995)
The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
The proportion of survivors in a group, e.g., of patients, studied and followed over a period, or the proportion of persons in a specified group alive at the beginning of a time interval who survive to the end of the interval. It is often studied using life table methods.
A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.
The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)
Elements of limited time intervals, contributing to particular results or situations.
Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.
In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.
The probability that an event will occur. It encompasses a variety of measures of the probability of a generally unfavorable outcome.
Factors which produce cessation of all vital bodily functions. They can be analyzed from an epidemiologic viewpoint.
Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.
Methods which attempt to express in replicable terms the extent of the neoplasm in the patient.
A range of values for a variable of interest, e.g., a rate, constructed so that this range has a specified probability of including the true value of the variable.
Period after successful treatment in which there is no appearance of the symptoms or effects of the disease.
Studies in which variables relating to an individual or group of individuals are assessed over a period of time.
All deaths reported in a given population.
Tumors or cancer of the human BREAST.
Pathological conditions involving the CARDIOVASCULAR SYSTEM including the HEART; the BLOOD VESSELS; or the PERICARDIUM.
The systems and processes involved in the establishment, support, management, and operation of registers, e.g., disease registers.
A cancer registry mandated under the National Cancer Act of 1971 to operate and maintain a population-based cancer reporting system, reporting periodically estimates of cancer incidence and mortality in the United States. The Surveillance, Epidemiology, and End Results (SEER) Program is a continuing project of the National Cancer Institute of the National Institutes of Health. Among its goals, in addition to assembling and reporting cancer statistics, are the monitoring of annual cancer incident trends and the promoting of studies designed to identify factors amenable to cancer control interventions. (From National Cancer Institute, NIH Publication No. 91-3074, October 1990)
Inhaling and exhaling the smoke of burning TOBACCO.
Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.
Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.
The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis.
The local recurrence of a neoplasm following treatment. It arises from microscopic cells of the original neoplasm that have escaped therapeutic intervention and later become clinically visible at the original site.
Factors that can cause or prevent the outcome of interest, are not intermediate variables, and are not associated with the factor(s) under investigation. They give rise to situations in which the effects of two processes are not separated, or the contribution of causal factors cannot be separated, or the measure of the effect of exposure or risk is distorted because of its association with other factors influencing the outcome of the study.
Molecular products metabolized and secreted by neoplastic tissue and characterized biochemically in cells or body fluids. They are indicators of tumor stage and grade as well as useful for monitoring responses to treatment and predicting recurrence. Many chemical groups are represented including hormones, antigens, amino and nucleic acids, enzymes, polyamines, and specific cell membrane proteins and lipids.
The end-stage of CHRONIC RENAL INSUFFICIENCY. It is characterized by the severe irreversible kidney damage (as measured by the level of PROTEINURIA) and the reduction in GLOMERULAR FILTRATION RATE to less than 15 ml per min (Kidney Foundation: Kidney Disease Outcome Quality Initiative, 2002). These patients generally require HEMODIALYSIS or KIDNEY TRANSPLANTATION.
A group of pathological conditions characterized by sudden, non-convulsive loss of neurological function due to BRAIN ISCHEMIA or INTRACRANIAL HEMORRHAGES. Stroke is classified by the type of tissue NECROSIS, such as the anatomic location, vasculature involved, etiology, age of the affected individual, and hemorrhagic vs. non-hemorrhagic nature. (From Adams et al., Principles of Neurology, 6th ed, pp777-810)
The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival.
The return of a sign, symptom, or disease after a remission.
An indicator of body density as determined by the relationship of BODY WEIGHT to BODY HEIGHT. BMI=weight (kg)/height squared (m2). BMI correlates with body fat (ADIPOSE TISSUE). Their relationship varies with age and gender. For adults, BMI falls into these categories: below 18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0 and above (obese). (National Center for Health Statistics, Centers for Disease Control and Prevention)
Individuals whose ancestral origins are in the continent of Europe.
Tumors or cancer of the PROSTATE.
A distribution in which a variable is distributed like the sum of the squares of any given independent random variable, each of which has a normal distribution with mean of zero and variance of one. The chi-square test is a statistical test based on comparison of a test statistic to a chi-square distribution. The oldest of these tests are used to detect whether two or more population distributions differ from one another.
The ratio of two odds. The exposure-odds ratio for case control data is the ratio of the odds in favor of exposure among cases to the odds in favor of exposure among noncases. The disease-odds ratio for a cohort or cross section is the ratio of the odds in favor of disease among the exposed to the odds in favor of disease among the unexposed. The prevalence-odds ratio refers to an odds ratio derived cross-sectionally from studies of prevalent cases.
NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).
Therapy for the insufficient cleansing of the BLOOD by the kidneys based on dialysis and including hemodialysis, PERITONEAL DIALYSIS, and HEMODIAFILTRATION.
An imbalance between myocardial functional requirements and the capacity of the CORONARY VESSELS to supply sufficient blood flow. It is a form of MYOCARDIAL ISCHEMIA (insufficient blood supply to the heart muscle) caused by a decreased capacity of the coronary vessels.
Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.
Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.
Tumors or cancer of the COLON or the RECTUM or both. Risk factors for colorectal cancer include chronic ULCERATIVE COLITIS; FAMILIAL POLYPOSIS COLI; exposure to ASBESTOS; and irradiation of the CERVIX UTERI.
Tumors or cancer of the LUNG.
Transfer of a neoplasm from its primary site to lymph nodes or to distant parts of the body by way of the lymphatic system.
Research techniques that focus on study designs and data gathering methods in human and animal populations.
The physiological period following the MENOPAUSE, the permanent cessation of the menstrual life.
Regular course of eating and drinking adopted by a person or animal.
Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).
A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (VENTRICULAR DYSFUNCTION), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as MYOCARDIAL INFARCTION.
The confinement of a patient in a hospital.
New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms.
Persons living in the United States having origins in any of the black groups of Africa.
Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.
A malignant epithelial tumor with a glandular organization.
The frequency of different ages or age groups in a given population. The distribution may refer to either how many or what proportion of the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.
A beverage made from ground COFFEA beans (SEEDS) infused in hot water. It generally contains CAFFEINE and THEOPHYLLINE unless it is decaffeinated.
Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.
Behaviors associated with the ingesting of alcoholic beverages, including social drinking.
A subclass of DIABETES MELLITUS that is not INSULIN-responsive or dependent (NIDDM). It is characterized initially by INSULIN RESISTANCE and HYPERINSULINEMIA; and eventually by GLUCOSE INTOLERANCE; HYPERGLYCEMIA; and overt diabetes. Type II diabetes mellitus is no longer considered a disease exclusively found in adults. Patients seldom develop KETOSIS but often exhibit OBESITY.
The treatment of a disease or condition by several different means simultaneously or sequentially. Chemoimmunotherapy, RADIOIMMUNOTHERAPY, chemoradiotherapy, cryochemotherapy, and SALVAGE THERAPY are seen most frequently, but their combinations with each other and surgery are also used.
Drug regimens, for patients with HIV INFECTIONS, that aggressively suppress HIV replication. The regimens usually involve administration of three or more different drugs including a protease inhibitor.
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
The number of CD4-POSITIVE T-LYMPHOCYTES per unit volume of BLOOD. Determination requires the use of a fluorescence-activated flow cytometer.
A heterogeneous group of disorders characterized by HYPERGLYCEMIA and GLUCOSE INTOLERANCE.
A food group comprised of EDIBLE PLANTS or their parts.
Conditional probability of exposure to a treatment given observed covariates.
Drug therapy given to augment or stimulate some other form of treatment such as surgery or radiation therapy. Adjuvant chemotherapy is commonly used in the therapy of cancer and can be administered before or after the primary treatment.
Extensive collections, reputedly complete, of facts and data garnered from material of a specialized subject area and made available for analysis and application. The collection can be automated by various contemporary methods for retrieval. The concept should be differentiated from DATABASES, BIBLIOGRAPHIC which is restricted to collections of bibliographic references.
The number of males and females in a given population. The distribution may refer to how many men or women or what proportion of either in the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.
Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.
Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.
Individuals whose ancestral origins are in the continent of Africa.
Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.
Continuance of life or existence especially under adverse conditions; includes methods and philosophy of survival.
The study of chance processes or the relative frequency characterizing a chance process.
The concept covering the physical and mental conditions of women.
Acquired or learned food preferences.
A glycoprotein that is a kallikrein-like serine proteinase and an esterase, produced by epithelial cells of both normal and malignant prostate tissue. It is an important marker for the diagnosis of prostate cancer.
Typical way of life or manner of living characteristic of an individual or group. (From APA, Thesaurus of Psychological Index Terms, 8th ed)
Fractures of the FEMUR HEAD; the FEMUR NECK; (FEMORAL NECK FRACTURES); the trochanters; or the inter- or subtrochanteric region. Excludes fractures of the acetabulum and fractures of the femoral shaft below the subtrochanteric region (FEMORAL FRACTURES).
Tumors or cancer of the LIVER.
Conditions or pathological processes associated with the disease of diabetes mellitus. Due to the impaired control of BLOOD GLUCOSE level in diabetic patients, pathological processes develop in numerous tissues and organs including the EYE, the KIDNEY, the BLOOD VESSELS, and the NERVE TISSUE.
Social and economic factors that characterize the individual or group within the social structure.
A measure of the quality of health care by assessment of unsuccessful results of management and procedures used in combating disease, in individual cases or series.
The age, developmental stage, or period of life at which a disease or the initial symptoms or manifestations of a disease appear in an individual.
Complete or partial surgical removal of the prostate. Three primary approaches are commonly employed: suprapubic - removal through an incision above the pubis and through the urinary bladder; retropubic - as for suprapubic but without entering the urinary bladder; and transurethral (TRANSURETHRAL RESECTION OF PROSTATE).
Works about clinical trials that involve at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
A country spanning from central Asia to the Pacific Ocean.
A carcinoma derived from stratified SQUAMOUS EPITHELIAL CELLS. It may also occur in sites where glandular or columnar epithelium is normally present. (From Stedman, 25th ed)
Tumors or cancer of the OVARY. These neoplasms can be benign or malignant. They are classified according to the tissue of origin, such as the surface EPITHELIUM, the stromal endocrine cells, and the totipotent GERM CELLS.
Cytoplasmic proteins that bind estrogens and migrate to the nucleus where they regulate DNA transcription. Evaluation of the state of estrogen receptors in breast cancer patients has become clinically important.
Elements of residence that characterize a population. They are applicable in determining need for and utilization of health services.
Agents used to treat AIDS and/or stop the spread of the HIV infection. These do not include drugs used to treat symptoms or opportunistic infections associated with AIDS.
An acquired organic mental disorder with loss of intellectual abilities of sufficient severity to interfere with social or occupational functioning. The dysfunction is multifaceted and involves memory, behavior, personality, judgment, attention, spatial relations, language, abstract thought, and other executive functions. The intellectual decline is usually progressive, and initially spares the level of consciousness.
The use of statistical and mathematical methods to analyze biological observations and phenomena.
The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.
The fleshy or dry ripened ovary of a plant, enclosing the seed or seeds.
Tumors or cancer of ENDOMETRIUM, the mucous lining of the UTERUS. These neoplasms can be benign or malignant. Their classification and grading are based on the various cell types and the percent of undifferentiated cells.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
Works about controlled studies which are planned and carried out by several cooperating institutions to assess certain variables and outcomes in specific patient populations, for example, a multicenter study of congenital anomalies in children.
A systematic collection of factual data pertaining to health and disease in a human population within a given geographic area.
Tumors or cancer of the STOMACH.
Systematic collections of factual data pertaining to the diet of a human population within a given geographic area.
Summarizing techniques used to describe the pattern of mortality and survival in populations. These methods can be applied to the study not only of death, but also of any defined endpoint such as the onset of disease or the occurrence of disease complications.
A primary malignant neoplasm of epithelial liver cells. It ranges from a well-differentiated tumor with EPITHELIAL CELLS indistinguishable from normal HEPATOCYTES to a poorly differentiated neoplasm. The cells may be uniform or markedly pleomorphic, or form GIANT CELLS. Several classification schemes have been suggested.
Methods which attempt to express in replicable terms the level of CELL DIFFERENTIATION in neoplasms as increasing ANAPLASIA correlates with the aggressiveness of the neoplasm.
The use of hormonal agents with estrogen-like activity in postmenopausal or other estrogen-deficient women to alleviate effects of hormone deficiency, such as vasomotor symptoms, DYSPAREUNIA, and progressive development of OSTEOPOROSIS. This may also include the use of progestational agents in combination therapy.
Tumors or cancer of the ESOPHAGUS.
Country located in EUROPE. It is bordered by the NORTH SEA, BELGIUM, and GERMANY. Constituent areas are Aruba, Curacao, Sint Maarten, formerly included in the NETHERLANDS ANTILLES.
Specific proteins found in or on cells of progesterone target tissues that specifically combine with progesterone. The cytosol progesterone-receptor complex then associates with the nucleic acids to initiate protein synthesis. There are two kinds of progesterone receptors, A and B. Both are induced by estrogen and have short half-lives.
A carotenoid that is a precursor of VITAMIN A. It is administered to reduce the severity of photosensitivity reactions in patients with erythropoietic protoporphyria (PORPHYRIA, ERYTHROPOIETIC). (From Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Engewood, CO, 1995.)
Former members of the armed services.
Ability of neoplasms to infiltrate and actively destroy surrounding tissue.
A graphic means for assessing the ability of a screening test to discriminate between healthy and diseased persons; may also be used in other studies, e.g., distinguishing stimuli responses as to a faint stimuli or nonstimuli.
Pathological processes of CORONARY ARTERIES that may derive from a congenital abnormality, atherosclerotic, or non-atherosclerotic cause.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
The volume of water filtered out of plasma through glomerular capillary walls into Bowman's capsules per unit of time. It is considered to be equivalent to INULIN clearance.
A heterogeneous aggregate of at least three distinct histological types of lung cancer, including SQUAMOUS CELL CARCINOMA; ADENOCARCINOMA; and LARGE CELL CARCINOMA. They are dealt with collectively because of their shared treatment strategy.
Application of statistical procedures to analyze specific observed or assumed facts from a particular study.
Tumors or cancers of the KIDNEY.
The use of two or more chemicals simultaneously or sequentially in the drug therapy of neoplasms. The drugs need not be in the same dosage form.
Research aimed at assessing the quality and effectiveness of health care as measured by the attainment of a specified end result or outcome. Measures include parameters such as improved health, lowered morbidity or mortality, and improvement of abnormal states (such as elevated blood pressure).
A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
Federal program, created by Public Law 89-97, Title XVIII-Health Insurance for the Aged, a 1965 amendment to the Social Security Act, that provides health insurance benefits to persons over the age of 65 and others eligible for Social Security benefits. It consists of two separate but coordinated programs: hospital insurance (MEDICARE PART A) and supplementary medical insurance (MEDICARE PART B). (Hospital Administration Terminology, AHA, 2d ed and A Discursive Dictionary of Health Care, US House of Representatives, 1976)
Radiotherapy given to augment some other form of treatment such as surgery or chemotherapy. Adjuvant radiotherapy is commonly used in the therapy of cancer and can be administered before or after the primary treatment.
Unexpected rapid natural death due to cardiovascular collapse within one hour of initial symptoms. It is usually caused by the worsening of existing heart diseases. The sudden onset of symptoms, such as CHEST PAIN and CARDIAC ARRHYTHMIAS, particularly VENTRICULAR TACHYCARDIA, can lead to the loss of consciousness and cardiac arrest followed by biological death. (from Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 7th ed., 2005)
Irreversible cessation of all bodily functions, manifested by absence of spontaneous breathing and total loss of cardiovascular and cerebral functions.
Tumors or cancer of the PANCREAS. Depending on the types of ISLET CELLS present in the tumors, various hormones can be secreted: GLUCAGON from PANCREATIC ALPHA CELLS; INSULIN from PANCREATIC BETA CELLS; and SOMATOSTATIN from the SOMATOSTATIN-SECRETING CELLS. Most are malignant except the insulin-producing tumors (INSULINOMA).
Neoplasms of the intracranial components of the central nervous system, including the cerebral hemispheres, basal ganglia, hypothalamus, thalamus, brain stem, and cerebellum. Brain neoplasms are subdivided into primary (originating from brain tissue) and secondary (i.e., metastatic) forms. Primary neoplasms are subdivided into benign and malignant forms. In general, brain tumors may also be classified by age of onset, histologic type, or presenting location in the brain.
Raw and processed or manufactured milk and milk-derived products. These are usually from cows (bovine) but are also from goats, sheep, reindeer, and water buffalo.
A plasma protein that circulates in increased amounts during inflammation and after tissue damage.
Persons who have experienced a prolonged survival after serious disease or who continue to live with a usually life-threatening condition as well as family members, significant others, or individuals surviving traumatic life events.
The transfer of a neoplasm from one organ or part of the body to another remote from the primary site.
An operating division of the US Department of Health and Human Services. It is concerned with the overall planning, promoting, and administering of programs pertaining to health and medical research. Until 1995, it was an agency of the United States PUBLIC HEALTH SERVICE.
The last menstrual period. Permanent cessation of menses (MENSTRUATION) is usually defined after 6 to 12 months of AMENORRHEA in a woman over 45 years of age. In the United States, menopause generally occurs in women between 48 and 55 years of age.
A group of people with a common cultural heritage that sets them apart from others in a variety of social relationships.
An important aggregate factor in epidemiological studies of women's health. The concept usually includes the number and timing of pregnancies and their outcomes, the incidence of breast feeding, and may include age of menarche and menopause, regularity of menstruation, fertility, gynecological or obstetric problems, or contraceptive usage.
A heterogeneous group of sporadic or hereditary carcinoma derived from cells of the KIDNEYS. There are several subtypes including the clear cells, the papillary, the chromophobe, the collecting duct, the spindle cells (sarcomatoid), or mixed cell-type carcinoma.
Graphical representation of a statistical model containing scales for calculating the prognostic weight of a value for each individual variable. Nomograms are instruments that can be used to predict outcomes using specific clinical parameters. They use ALGORITHMS that incorporate several variables to calculate the predicted probability that a patient will achieve a particular clinical endpoint.
Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)
A status with BODY WEIGHT that is grossly above the acceptable or desirable weight, usually due to accumulation of excess FATS in the body. The standards may vary with age, sex, genetic or cultural background. In the BODY MASS INDEX, a BMI greater than 30.0 kg/m2 is considered obese, and a BMI greater than 40.0 kg/m2 is considered morbidly obese (MORBID OBESITY).
The application of STATISTICS to biological systems and organisms involving the retrieval or collection, analysis, reduction, and interpretation of qualitative and quantitative data.
A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.
The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.
A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.
Ongoing scrutiny of a population (general population, study population, target population, etc.), generally using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy.
Products in capsule, tablet or liquid form that provide dietary ingredients, and that are intended to be taken by mouth to increase the intake of nutrients. Dietary supplements can include macronutrients, such as proteins, carbohydrates, and fats; and/or MICRONUTRIENTS, such as VITAMINS; MINERALS; and PHYTOCHEMICALS.
Abnormal growths of tissue that follow a previous neoplasm but are not metastases of the latter. The second neoplasm may have the same or different histological type and can occur in the same or different organs as the previous neoplasm but in all cases arises from an independent oncogenic event. The development of the second neoplasm may or may not be related to the treatment for the previous neoplasm since genetic risk or predisposing factors may actually be the cause.
Any deviation of results or inferences from the truth, or processes leading to such deviation. Bias can result from several sources: one-sided or systematic variations in measurement from the true value (systematic error); flaws in study design; deviation of inferences, interpretations, or analyses based on flawed data or data collection; etc. There is no sense of prejudice or subjectivity implied in the assessment of bias under these conditions.
Dialysis fluid being introduced into and removed from the peritoneal cavity as either a continuous or an intermittent procedure.
Lack of perfusion in the EXTREMITIES resulting from atherosclerosis. It is characterized by INTERMITTENT CLAUDICATION, and an ANKLE BRACHIAL INDEX of 0.9 or less.
Tumors or cancer of the COLON.
Compounds that inhibit HMG-CoA reductases. They have been shown to directly lower cholesterol synthesis.
The survival of a graft in a host, the factors responsible for the survival and the changes occurring within the graft during growth in the host.
Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.
Educational attainment or level of education of individuals.
Breaks in bones.
The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.
Diseases caused by factors involved in one's employment.
The transference of a kidney from one human or animal to another.
A province of Canada on the Pacific coast. Its capital is Victoria. The name given in 1858 derives from the Columbia River which was named by the American captain Robert Gray for his ship Columbia which in turn was named for Columbus. (From Webster's New Geographical Dictionary, 1988, p178 & Room, Brewer's Dictionary of Names, 1992, p81-2)
Pathological processes of the KIDNEY or its component tissues.
Individuals whose ancestral origins are in the southeastern and eastern areas of the Asian continent.
A group of islands in Polynesia, in the north central Pacific Ocean, comprising eight major and 114 minor islands, largely volcanic and coral. Its capital is Honolulu. It was first reached by Polynesians about 500 A.D. It was discovered and named the Sandwich Islands in 1778 by Captain Cook. The islands were united under the rule of King Kamehameha 1795-1819 and requested annexation to the United States in 1893 when a provisional government was set up. Hawaii was established as a territory in 1900 and admitted as a state in 1959. The name is from the Polynesian Owhyhii, place of the gods, with reference to the two volcanoes Mauna Kea and Mauna Loa, regarded as the abode of the gods. (From Webster's New Geographical Dictionary, 1988, p493 & Room, Brewer's Dictionary of Names, 1992, p2330)
An adenocarcinoma producing mucin in significant amounts. (From Dorland, 27th ed)
An infant during the first month after birth.
A malignant neoplasm made up of epithelial cells tending to infiltrate the surrounding tissues and give rise to metastases. It is a histological type of neoplasm but is often wrongly used as a synonym for "cancer." (From Dorland, 27th ed)
The largest country in North America, comprising 10 provinces and three territories. Its capital is Ottawa.
The proportion of patients with a particular disease during a given year per given unit of population.
A performance measure for rating the ability of a person to perform usual activities, evaluating a patient's progress after a therapeutic procedure, and determining a patient's suitability for therapy. It is used most commonly in the prognosis of cancer therapy, usually after chemotherapy and customarily administered before and after therapy. It was named for Dr. David A. Karnofsky, an American specialist in cancer chemotherapy.
The quantity of measurable virus in a body fluid. Change in viral load, measured in plasma, is sometimes used as a SURROGATE MARKER in disease progression.
Neoplasms composed of glandular tissue, an aggregation of epithelial cells that elaborate secretions, and of any type of epithelium itself. The concept does not refer to neoplasms located in the various glands or in epithelial tissue.
Professionals qualified by graduation from an accredited school of nursing and by passage of a national licensing examination to practice nursing. They provide services to patients requiring assistance in recovering or maintaining their physical or mental health.
Groups of individuals whose putative ancestry is from native continental populations based on similarities in physical appearance.
A malignant neoplasm derived from cells that are capable of forming melanin, which may occur in the skin of any part of the body, in the eye, or, rarely, in the mucous membranes of the genitalia, anus, oral cavity, or other sites. It occurs mostly in adults and may originate de novo or from a pigmented nevus or malignant lentigo. Melanomas frequently metastasize widely, and the regional lymph nodes, liver, lungs, and brain are likely to be involved. The incidence of malignant skin melanomas is rising rapidly in all parts of the world. (Stedman, 25th ed; from Rook et al., Textbook of Dermatology, 4th ed, p2445)
Breaks in bones resulting from low bone mass and microarchitectural deterioration characteristic of OSTEOPOROSIS.
A repeat operation for the same condition in the same patient due to disease progression or recurrence, or as followup to failed previous surgery.
Computer-based representation of physical systems and phenomena such as chemical processes.
Criteria and standards used for the determination of the appropriateness of the inclusion of patients with specific conditions in proposed treatment plans and the criteria used for the inclusion of subjects in various clinical trials and other research protocols.

Microvascular loops and networks as prognostic indicators in choroidal and ciliary body melanomas. (1/14874)

BACKGROUND: Malignant melanoma of the ciliary body and choroid of the eye is a tumor that disseminates frequently, and 50% of the diagnosed patients die within 10 years. We investigated the hypothesis that, by histopathologic analysis of the arrangement of microvessels (i.e., small blood vessels) in loops and networks, we might be able to differentiate better those patients with a favorable prognosis from those with a poor prognosis. METHODS: We conducted a population-based, retrospective cohort study of melanoma-specific and all-cause mortality for 167 consecutive patients who had an eye surgically removed because of malignant choroidal or ciliary body melanoma during the period from 1972 through 1981. Microvascular loops and networks were evaluated independently by two pathologists who were unaware of patient outcome. RESULTS: Microvascular patterns could be assessed in 134 (80%) of 167 melanoma specimens. The 10-year probability of melanoma-specific survival was worse if microvascular loops (0.45 versus 0.83; two-sided P<.0001) and networks (0.41 versus 0.72, two-sided P<.0001) were present. In multivariate Cox regression analysis of melanoma-specific survival, the hazard ratios were 1.66 (95% confidence interval [CI] = 1.19-2.30) for the presence of loops and networks as a combined three-category variable, 2.36 (95% CI = 1.37-4.05) for the presence of epithelioid cells, 1.11 (95% CI = 1.03-1.19) for the largest basal tumor diameter (evaluated as a continuous variable), and 2.14 (95% CI = 1.25-3.67) for ciliary body involvement. CONCLUSIONS: Patients with malignant uveal melanoma who have a favorable prognosis can be distinguished from those with a poor prognosis by histopathologic analysis of microvascular patterns in uveal melanoma tumor specimens.  (+info)

Effects of calcium-channel blockade in older patients with diabetes and systolic hypertension. Systolic Hypertension in Europe Trial Investigators. (2/14874)

BACKGROUND: Recent reports suggest that calcium-channel blockers may be harmful in patients with diabetes and hypertension. We previously reported that antihypertensive treatment with the calcium-channel blocker nitrendipine reduced the risk of cardiovascular events. In this post hoc analysis, we compared the outcome of treatment with nitrendipine in diabetic and nondiabetic patients. METHODS: After stratification according to center, sex, and presence or absence of previous cardiovascular complications, 4695 patients (age, > or =60 years) with systolic blood pressure of 160 to 219 mm Hg and diastolic pressure below 95 mm Hg were randomly assigned to receive active treatment or placebo. Active treatment consisted of nitrendipine (10 to 40 mg per day) with the possible addition or substitution of enalapril (5 to 20 mg per day) or hydrochlorothiazide (12.5 to 25 mg per day) or both, titrated to reduce the systolic blood pressure by at least 20 mm Hg and to less than 150 mm Hg. In the control group, matching placebo tablets were administered similarly. RESULTS: At randomization, 492 patients (10.5 percent) had diabetes. After a median follow-up of two years, the systolic and diastolic blood pressures in the placebo and active-treatment groups differed by 8.6 and 3.9 mm Hg, respectively, among the diabetic patients. Among the 4203 patients without diabetes, systolic and diastolic pressures differed by 10.3 and 4.5 mm Hg, respectively, in the two groups. After adjustment for possible confounders, active treatment was found to have reduced overall mortality by 55 percent (from 45.1 deaths per 1000 patients to 26.4 deaths per 1000 patients), mortality from cardiovascular disease by 76 percent, all cardiovascular events combined by 69 percent, fatal and nonfatal strokes by 73 percent, and all cardiac events combined by 63 percent in the group of patients with diabetes. Among the nondiabetic patients, active treatment decreased all cardiovascular events combined by 26 percent and fatal and nonfatal strokes by 38 percent. In the group of patients receiving active treatment, reductions in overall mortality, mortality from cardiovascular disease, and all cardiovascular events were significantly larger among the diabetic patients than among the nondiabetic patients (P=0.04, P=0.02, and P=0.01, respectively). CONCLUSIONS: Nitrendipine-based antihypertensive therapy is particularly beneficial in older patients with diabetes and isolated systolic hypertension. Thus, our findings do not support the hypothesis that the use of long-acting calcium-channel blockers may be harmful in diabetic patients.  (+info)

Association between age and survival following major amputation. The Scottish Vascular Audit Group. (3/14874)

OBJECTIVES: To determine whether age is associated with survival following major amputation and whether this association is independent or simply reflects selection bias in amputation level. DESIGN AND MATERIALS: Computer linkage of routine discharge and death data on the 2759 patients undergoing major amputation in Scotland between 1989 and 1993 for peripheral arterial disease. METHODS: Cox's proportional hazards model and multivariate logistic regression analysis using death as the outcome variable and age, sex, urgency, amputation level and recent arterial reconstructive surgery as predictor variables. RESULTS: Proximal amputation was more common in older patients. Survival was associated with both age (p < 0.001) and amputation level (p < 0.001). Age was an independent predictor of death at 30 days (p < 0.0001), 6 months (p < 0.001), 12 months (p < 0.0001) and 2 years (p < 0.0001) postoperation. CONCLUSIONS: Survival following amputation was poor, with only half the patients alive at 2 years. Above-knee amputation was associated with poorer survival, presumably due to the presence of more severe and widespread disease, and was undertaken more commonly in older patients. However, age remained a predictor of survival after adjustment for amputation level. Higher early mortality suggest that a worse prognosis in elderly patients cannot be attributed wholly to actuarial considerations.  (+info)

Prognostic value of ECG findings for total, cardiovascular disease, and coronary heart disease death in men and women. (4/14874)

OBJECTIVE: To study abnormalities in the resting ECG as independent predictors for all cause, cardiovascular disease (CVD), and coronary heart disease (CHD) mortality in a population based random sample of men and women, and to explore whether their prognostic value is different between sexes. DESIGN AND SUBJECTS: An age and sex stratified random sample was selected from the total Belgian population aged 25 to 74 years. Baseline data were gathered and resting ECGs were classified according to Minnesota code criteria. The sample was then followed for at least 10 years with respect to cause specific death. Results are based on observations from 5208 men and 4746 women free from prevalent CHD at the start of the follow up period. RESULTS: Although the prevalence of major abnormalities in general was comparable between sexes, women had more ischaemic findings, ST segment changes, and abnormal T waves on their baseline ECG, while men showed more arrhythmias, bundle branch blocks, and left ventricular hypertrophy. Fitting the multiplicative effect on subsequent mortality between all ECG classifications under study and sex indicated that the prognostic value of ECG changes was equal in women and men. Independently of other risk factors and other major ECG changes, almost all ECG classifications were significantly related to all cause, CVD, and CHD mortality. The most predictive ECG findings for CVD death were ST segment depression (risk ratio (RR) 4.71), major ECG findings (RR 3.26), left ventricular hypertrophy (RR 2.79), bundle branch blocks (RR 2.58), T wave flattening (RR 2.47), ischaemic ECG findings (RR 2.35), and arrhythmias (RR 2.15). The prognostic value of major ECG findings for CVD and CHD death was more powerful than well established cardiovascular risk factors. CONCLUSIONS: Abnormalities in the baseline ECG are strongly associated with subsequent all cause, CVD, and CHD mortality. Their predictive value was similar for men and women.  (+info)

Recurrence in affective disorder: analyses with frailty models. (5/14874)

The risk of recurrence in affective disorder is influenced by the number of prior episodes and by a person's tendency toward recurrence. Newly developed frailty models were used to estimate the effect of the number of episodes on the rate of recurrence, taking into account individual frailty toward recurrence. The study base was the Danish psychiatric case register of all hospital admissions for primary affective disorder in Denmark during 1971-1993. A total of 20,350 first-admission patients were discharged with a diagnosis of major affective disorder. For women with unipolar disorder and for all kinds of patients with bipolar disorder, the rate of recurrence was affected by the number of prior episodes even when the effect was adjusted for individual frailty toward recurrence. No effect of episodes but a large effect of the frailty parameter was found for unipolar men. The authors concluded that the risk of recurrence seems to increase with the number of episodes of bipolar affective disorder in general and for women with unipolar disorder.  (+info)

Influence of a family history of cancer within and across multiple sites on patterns of cancer mortality risk for women. (6/14874)

A case-control study nested within a large cohort, the American Cancer Society Cancer Prevention Study-1, was conducted to test associations between a family history of cancer and cancer mortality in women. By using logistic regression, the authors analyzed family history, as reported by 429,483 women enrolled in 1959, relative to subsequent mortality through 1972 from cancer within and across multiple sites. The associations between family history and cancer mortality were generally stronger within cancer sites than across cancer sites. Within-site associations were found for breast cancer (odds ratio (OR) = 1.9), colorectal cancer (OR = 1.6), stomach cancer (OR = 1.9), and lung cancer (OR = 1.7). Across-site associations were observed for a family history of 1) breast cancer as a risk factor for ovarian cancer mortality (OR = 1.6), 2) stomach cancer as a risk factor for ovarian cancer mortality (OR = 1.5), and 3) uterine cancer as a risk factor for pancreatic cancer mortality (OR = 1.6). A general pattern of positive associations was observed between a family history of cancer at several sites and subsequent death from pancreatic cancer. These findings support the growing body of evidence from cancer genetics suggesting that inherited cancer-susceptibility genes increase the risk for cancer at many sites and are not specific to cancer risk within a single site.  (+info)

Prognostic significance of extent of disease in bone in patients with androgen-independent prostate cancer. (7/14874)

PURPOSE: To evaluate the prognostic significance of a bone scan index (BSI) based on the weighted proportion of tumor involvement in individual bones, in relation to other factors and to survival in patients with androgen-independent prostate cancer. PATIENTS AND METHODS: Baseline radionuclide bone scans were reviewed in 191 assessable patients with androgen-independent disease who were enrolled onto an open, randomized trial of liarozole versus prednisone. The extent of skeletal involvement was assessed by scoring each scan using the BSI and independently according to the number of metastatic lesions. The relationship of the scored bone involvement to other known prognostic factors was explored in single- and multiple-variable analyses. RESULTS: In single-variable analyses, the pretreatment factors found to be associated with survival were age (P = .0446), performance status (P = .0005), baseline prostate-specific antigen (P = .0001), hemoglobin (P = .0001), alkaline phosphatase (P = .0002), AST (P = .0021), lactate dehydrogenase (P = .0001), and treatment (P = .0098). The extent of osseous disease was significant using both the BSI (P = .0001) and the number of lesions present (P = .0001). In multiple-variable proportional hazards analyses, only BSI, age, hemoglobin, lactate dehydrogenase, and treatment arm were associated with survival. When the patient population was divided into three equal groups, with BSI values of < 1.4%, 1.4% to 5.1%, and > 5.1%, median survivals of 18.3, 15.5, and 8.1 months, respectively, were observed (P = .0079). CONCLUSION: The BSI quantifies the extent of skeletal involvement by tumor. It allows the identification of patients with distinct prognoses for stratification in clinical trials. Further study is needed to assess the utility of serial BSI determinations in monitoring treatment effects. The BSI may be particularly useful in the evaluation of agents for which prostate-specific antigen changes do not reflect clinical outcomes accurately.  (+info)

Hematocrit level and associated mortality in hemodialysis patients. (8/14874)

Although a number of clinical studies have shown that increased hematocrits are associated with improved outcomes in terms of cognitive function, reduced left ventricular hypertrophy, increased exercise tolerance, and improved quality of life, the optimal hematocrit level associated with survival has yet to be determined. The association between hematocrit levels and patient mortality was retrospectively studied in a prevalent Medicare hemodialysis cohort on a national scale. All patients survived a 6-mo entry period during which their hematocrit levels were assessed, from July 1 through December 31, 1993, with follow-up from January 1 through December 31, 1994. Patient comorbid conditions relative to clinical events and severity of disease were determined from Medicare claims data and correlated with the entry period hematocrit level. After adjusting for medical diseases, our results showed that patients with hematocrit levels less than 30% had significantly higher risk of all-cause (12 to 33%) and cause-specific death, compared to patients with hematocrits in the 30% to less than 33% range. Without severity of disease adjustment, patients with hematocrit levels of 33% to less than 36% appear to have the lowest risk for all-cause and cardiac mortality. After adjusting for severity of disease, the impact of hematocrit levels of 33% to less than 36% is vulnerable to the patient sample size but also demonstrates a further 4% reduced risk of death. Overall, these findings suggest that sustained increases in hematocrit levels are associated with improved patient survival.  (+info)

As stated above, you can use the survreg function. A note though: this is not strictly a Cox PH model, but rather location-scale models. Using the default log-transformation, this is the aft model. In the case of the exponential distribution, the proportional hazards and aft model are equivalent, so if distribution is set to exponential, this is a proportional hazards model with an exponential baseline. Likewise, if a baseline Weibull distribution aft model is used, the parameter estimates are just a linear transformation of those used in the proportional hazards model with Weibull baseline distribution. But in general, survreg does not fit a Cox PH model. If a semi-parametric model is desired, as found implemented in intcox, a word of caution: there are several issues with the current version of intcox (algorithm typically prematurely terminates significantly far from the MLE, fails outright with uncensored observations, no standard errors automatically presented). A new alternative that you ...
This command performs Cox-Proportional Hazards and Extended Cox-Proportional Hazards survival analysis. This form of survival analysis relates covariates to failure through hazard ratios. A covariate with a hazard ratio greater than one causes failure. A covariate with a hazard ratio less than one improves survival. Some of the subjects may be unavailable prior to failure; the term censored is applied to them. COXPH is especially constructed to deal with this situation. Statistics showing the risk set by group and time can be written to an OUTTABLE for later formatting.. Syntax ...
Background: Physical activity (PA) is considered a cornerstone of diabetes mellitus management to prevent complications, but conclusive evidence is lacking. Methods: This prospective cohort study and meta-analysis of existing studies investigated the association between PA and mortality in individuals with diabetes. In the EPIC study (European Prospective Investigation Into Cancer and Nutrition), a cohort was defined of 5859 individuals with diabetes at baseline. Associations of leisure-time and total PA and walking with cardiovascular disease (CVD) and total mortality were studied using multivariable Cox proportional hazards regression models. Fixed-and random-effects meta-analyses of prospective studies published up to December 2010 were pooled with inverse variance weighting. Results: In the prospective analysis, total PA was associated with lower risk of CVD and total mortality. Compared with physically inactive persons, the lowest mortality risk was observed in moderately active persons: ...
We explore the benefits of applying a new proportional hazard model to analyze survival of breast cancer patients. As a parametric model, the hypertabastic survival model offers a closer fit to experimental data than Cox regression, and furthermore provides explicit survival and hazard functions which can be used as additional tools in the survival analysis. In addition, one of our main concerns is utilization of multiple gene expression variables. Our analysis treats the important issue of interaction of different gene signatures in the survival analysis. The hypertabastic proportional hazards model was applied in survival analysis of breast cancer patients. This model was compared, using statistical measures of goodness of fit, with models based on the semi-parametric Cox proportional hazards model and the parametric log-logistic and Weibull models. The explicit functions for hazard and survival were then used to analyze the dynamic behavior of hazard and survival functions. The hypertabastic model
BackgroundRadiotherapy is an effective treatment for intermediate/high-risk locally-advanced prostate cancer, however, |30% of patients relapse within five years. Clinicopathological parameters currently fail to identify patients prone to systemic relapse and those whom treatment intensification may be beneficial. The purpose of this study was to independently validate the performance of a 70-gene Metastatic Assay in a cohort of diagnostic biopsies from patients treated with radical radiotherapy and androgen deprivation therapy (ADT).Patients & MethodsA bridging cohort of prostate cancer diagnostic biopsy specimens was profiled to enable optimization of the Metastatic Assay threshold prior to further independent clinical validation in a cohort of diagnostic biopsies from patients treated with radical radiotherapy and ADT. Multivariable Cox proportional hazard regression analysis was used to assess assay performance in predicting biochemical failure-free survival (BFFS) and metastasis-free survival (MFS)
This course discusses survival analysis concepts with an emphasis on health care problems. The course focuses on the Cox proportional hazards model, not the parametric models, and is not designed for predictive modelers.
This course discusses survival analysis concepts with an emphasis on health care problems. The course focuses on the Cox proportional hazards model, not the parametric models, and is not designed for predictive modelers.
Background: As the aging issue and increased elderly esophageal cancer (EC) patients, we sought to study the clinical characteristics, treatment modality and outcomes of EC patients 70 years or older compared with those younger than 70 years old.. Methods: The national surveillance, epidemiology, and end results (SEER) database for the period from 1973 to 2013 was analyzed. The patient and treatment characteristics were compared between the age groups. Multivariate Cox proportional hazard regression analyses were also performed to identify independent prognostic factors. Propensity-score matching analyses (PSA) regarding survival after different treatments were also performed in locoregional EC.. Results: Compared with the younger group, patients 70 years or older were characterized by having a higher proportion of patients with female gender, white race, localized disease, non-adenocarcinoma and without any treatment, as well as inferior overall survival (OS) [hazard ratio (HR), 1.324] and ...
Background: Periodontal disease, a common disorder of the tissue surrounding and supporting the teeth, is a major cause of tooth loss in adults. Periodontal infection by oral microorganisms may have systemic effects and has been associated with several types of cancer. However, its association with liver cancer has only been examined in two prospective studies, both of which had very small number of liver cancer cases (n , 20).. Methods: We examined the association of tooth loss, as a proxy measure of periodontal infection, with primary liver cancer incidence and chronic liver disease mortality in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) study, a prospective cohort of male Finnish smokers (n = 29,096). Number of permanent teeth lost was assessed at study baseline (1985-1988). We used Cox proportional hazards models to calculate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). As a sensitivity analysis, we conducted a nested case-control study to ...
There is growing evidence linking time in range (TIR), an emerging metric for assessing glycemic control, to diabetes-related outcomes. We aimed to investigate the association between TIR and mortality in patients with type 2 diabetes.A total of 6,225 adult patients with type 2 diabetes were included from January 2005 to December 2015 from a single center in Shanghai, China. TIR was measured with continuous glucose monitoring at baseline, and the participants were stratified into four groups by TIR: ,85%, 71-85%, 51-70%, and ≤50%. Cox proportional hazards regression models were used to estimate the association between different levels of TIR and the risks of all-cause and cardiovascular disease (CVD) mortality.The mean age of the participants was 61.7 years at baseline. During a median follow-up of 6.9 years, 838 deaths were identified, 287 of which were due to CVD. The multivariable-adjusted hazard ratios associated with different levels of TIR (,85% [reference group], 71-85%, 51-70%, and ...
The profiles of patients with fulminant hepatic failure (FHF) from developing countries have not been reported earlier. The current study was conducted prospectively, at a single tertiary care center in India, to document the demographic and clinical characteristics, natural course, and causative profile of patients with FHF as well as to define simple prognostic markers in these patients. Four hundred twenty-three consecutive patients with FHF admitted from January 1987 to June 1993 were included in the study. Each patients serum was tested for various hepatotropic viruses. Univariate Coxs regression for 28 variables, multivariate Coxs proportional hazard regression, stepwise logistic regression, and Kaplan-Meier survival analysis were done to identify independent predictors of outcome at admission. All patients presented with encephalopathy within 4 weeks of onset of symptoms. Hepatotropic viruses were the likely cause in most of these patients. Hepatitis A (HAV), hepatitis B (HBV), ...
OBJECTIVE: Evaluate the incidence and predictors of HIV acquisition from outside partners in serodiscordant couples. METHODS: Demographic, behavioral, and clinical exposures were measured quarterly in a cohort of serodiscordant cohabiting couples in Zambia from 1995 to 2012 (n = 3049). Genetic analysis classified incident infections as those acquired from the study partner (linked) or acquired from an outside partner (unlinked). Factors associated with time to unlinked HIV infection were evaluated using multivariable Cox proportional hazards regression stratified by sex. RESULTS: There were 100 unlinked infections in couples followed for a median of 806 days. Forty-five infections occurred in women [1.85/100 couple-years; 95% confidence interval (CI): 1.35 to 2.47]. Risk of female unlinked infection (vs. nonseroconverting females) was associated with reporting being drunk weekly/daily vs. moderate/nondrinkers at baseline [adjusted hazard ratio (aHR) = 5.44; 95% CI: 1.03 to 28.73], genital ulcers ...
Methods This meta-analysis included data from individual patients with RA randomized to double-blind treatment with combination therapy of ADA+MTX vs. MTX monotherapy in Phase II/III clinical trials (ARMADA, DE019, PREMIER, and OPTIMA [first double-blind period]); the maximum double-blind trial duration was 2 years. All patients who received at least one dose of study drugs were included. The primary outcome was the time from baseline to a MACE, a composite of nonfatal myocardial infarction (MI), nonfatal stroke, and CV death. These component events were also studied separately. Events were adjudicated by a blinded external panel of 2 cardiologists and 1 neurologist. Times to events were compared between the ADA+MTX and MTX arms using Kaplan-Meier estimates of the cumulative risk and Cox proportional-hazards models stratified by trial. The sequential Holm procedure was used to account for testing of each MACE component. Multivariable Cox models were also applied, with stratification by trial and ...
Thirteen patients (7%) with SVR and 100 patients (30%) without SVR died after prolonged follow-up of our cohort, which was more than 4 times the number of deaths registered during the first data collection (n = 2 among patients with SVR and n = 24 among patients without SVR).11 There was a significant difference in the cumulative 10-year mortality rate between patients with SVR (8.9%; 95% CI, 3.3%-14.5%) and without SVR (26.0%; 95% CI, 20.2%-28.4%; P < .001) (Figure). Cox proportional hazards regression analysis showed that SVR was associated with a statistically significant reduction in the hazard of overall death (adjusted hazard ratio [HR], 0.26; 95% CI, 0.14-0.49; P < .001) (Table 3, model 1). Other baseline factors significantly associated with all-cause mortality in multivariate analysis were older age, HCV genotype 3 infection, higher Ishak fibrosis score, presence of diabetes, and a history of severe alcohol use. Patients with HCV genotype 3 infection were younger (median [IQR] age, 44 ...
Background NGR-hTNF (asn-gly-arg-human tumor necrosis factor) induces systemic release of cytokines and intratumoral infiltration of effector T cells. Intravenous infusion of NGR-hTNF is characterized by onset of IRR, mostly consisting of transient grade 1-2 chills. Incidence, predictors of development, and relationships with outcome of IRR were assessed across 5 phase 2 single-arm trials of NGR-hTNF.. Methods 205 patients (pts) with solid tumors received NGR-hTNF 0.8 µg/m2 every 3 weeks (q3w) given either alone in colon cancer (n = 45), liver cancer (n = 40), and mesothelioma (n = 55), or with doxorubicin in small-cell lung cancer (n = 28) and ovarian cancer (n = 37). Tumor assessment by RECIST was done q6w until progressive disease (PD). Logistic and Cox proportional-hazards regression models were used to analyze associations between IRR and outcome, in terms of response rate (RR, complete and partial response), disease control rate (DCR, rate of pts without PD at 6 weeks), and ...
Potential effect of various immunocompetent cells from ascitic fluid on overall survival calculated using Cox proportional-hazards regression model
在先前的三篇文章已經有介紹存活分析(Survival analysis)的使用時機、如何繪製存活曲線圖(Kaplan-Meier curve),以及如何比較「組別」之間的存活曲線是否有顯著差異(Log
From 1993 to 1997, 27?148 men and 29?863 women, aged 50 to 64 year, were recruited into the Danish prospective study Diet, Cancer and Health. During 11.9 years of follow-up we identified 2028 cases of incident MI (1487 men and 541 women). BMI, waist circumference (WC), hip circumference and BIA of body composition including body fat mass (BFM), body fat percentage and LBM were measured at baseline. We used Cox proportional hazard models with age as time axis and performed extensive control for confounding. Weight, BMI, classical estimates of abdominal obesity and BIA estimates of obesity showed significant positive associations with incident MI. However, BFM adjusted for WC showed no association. Low LBM was associated with a higher risk of incident MI in both genders, and high LBM was associated with a higher risk in men ...
Continuous data were presented as median and IQR and categorical data as counts and percentages.. Cox proportional hazard regression analysis was used to evaluate the effect of variables on the overall survival. We adjusted for established risk factors, cardiac status and renal function in a basic model, to account for potential confounding effects. The basic model was built from the variables age, gender, tumour entity (with n,5) and tumour stage, which were included as possible predictors in a stepwise forward Cox regression. The p value for entering the stepwise model was set to 0.05, and the p value for exclusion was set to 0.10. To assess the robustness of the basic model and to test against overfitting, an additional bootstrap procedure was performed, repeating the variable selection for each of a total of 500 samples using the same entering and exclusion criteria. The frequency of a variable entering the model was counted. Significant predictors of the stepwise Cox regression, which ...
Background: Adrenocortical carcinoma (ACC) is a rare malignancy with poor outcomes. Objectives: To analyze the clinicopathologic features, treatment patterns and outcomes of patients with ACC who received systemic therapy at our center. Patients and Methods: This was a retrospective study conducted in a tertiary cancer center in India. Patients aged 15 years and older who were diagnosed with ACC between January 2011 and December 2018 and received systemic therapy were included in this study. For tumor staging, the European Network for the Study of Adrenal Tumors (ENSAT) system was used. The outcomes were reported as progression-free survival (PFS) and overall survival (OS). All statistical calculations were performed using the SPSS statistical software for Windows version 20.0. Results: Out of the 106 patients with ACC, 54 who received systemic therapy were included in this study. The median age of the cohort was 43 years (range, 15-72); 32 (59.3%) were men. Five (9.2%) patients had ENSAT Stage ...
Purpose Biomarkers for early detection of disease progression in MBC are urgently needed. We explored on-treatment increase in ctDNA fraction as an early prognostic biomarker of subsequent disease progression. Methods Eighty four paired samples from 70 patients with MBC were analyzed for levels of ctDNA, CEA, and CA 15-3. Baseline specimens were collected at the time of initiation of a new line of therapy and on-treatment specimens were obtained 4-12 weeks later. Each patient underwent a CT scan of chest, abdomen and pelvis on 4-16 weeks (on average 7 weeks) later. Sequencing panel of 73 genes was used to quantify ctDNA. Genomic progression was predefined as an increase ≥25% in total MAF from baseline to on-treatment, in patients with MBC. Progression Free Survival (PFS) was estimated using univariate and multivariate Cox proportional hazards models, adjusting for tumor hormonal status, age at metastatic diagnosis, time elapsed and number of prior therapies received. Results Tumor-specific ...
Description: This course focuses on methods for analyzing time-to-event data. This course will explore non-parametric methods for analyzing time-to-event data like Life tables, the Kaplan-Meier method, the Nelson-Aalen method and the log-rank test. This course will also explore semi-parametric models such as the Cox proportional hazards regression models and parametric models inlcuding exponential, Weibull and log-logistic regression model ...
The nested case-control (NCC) design is widely used in epidemiologic studies as a cost-effective subcohort sampling method to study the association between a disease and its potential risk factors. NCC data are commonly analyzed using Thomas partial likelihood approach under the Cox proportional hazards model assumption. However, the linear modeling form in the Cox model may be insufficient for practical applications, especially when there are a large number of risk factors under investigation. In this paper, we consider a partially linear single index proportional hazards model, which includes a linear component for covariates of interest to yield easily interpretable results and a nonparametric single index component to adjust for multiple confounders effectively. We propose to approximate the nonparametric single index function by polynomial splines and estimate the parameters of interest using an iterative algorithm based on the partial likelihood. Asymptotic properties of the resulting ...
Supplementary MaterialsFigure S1: Immunological properties from the materials presented in desk S1. (1.2M) GUID:?47640B6B-0287-4C90-B672-118435E94B5F Amount S2: TNF- creation by individual macrophage-like THP-1 cells subsequent incubation with amphiphiles 1C21. TC supernatants had been supervised for cytokine creation via ELISA, and email address details are reported in pg/mL. All scholarly research were performed in two unbiased natural… Continue reading Supplementary MaterialsFigure S1: Immunological properties from the materials presented in desk. ...
Reliable biomarkers of apatinib response in gastric cancer (GC) are lacking. We investigated the association between early presence of common adverse events (AEs) and clinical outcomes in metastatic GC patients. We conducted a retrospective cohort study using data on 269 apatinib-treated GC patients in two clinical trials. AEs were assessed at baseline until 28 days after the last dose of apatinib. Clinical outcomes were compared between patients with and without hypertension (HTN), proteinuria, or hand and foot syndrome (HFS) in the first 4 weeks. Time-to-event variables were assessed using Kaplan-Meier methods and Cox proportional hazard regression models. Binary endpoints were assessed using logistic regression models. Landmark analyses were performed as sensitivity analyses. Predictive model was analyzed, and risk scores were calculated to predict overall survival. Presence of AEs in the first 4 weeks was associated with prolonged median overall survival (169 vs. 103 days, log-rank p = 0.0039;
Synonyms for Hazard function in Free Thesaurus. Antonyms for Hazard function. 108 synonyms for function: purpose, business, job, concern, use, part, office, charge, role, post, operation, situation, activity, exercise, responsibility.... What are synonyms for Hazard function?
Methods: A total of 737 patients with dilated cardiomyopathy clinically referred for CMR-based evaluation were prospectively enrolled in the Cardiovascular Imaging Registry of Calgary (CIROC) between January 2015 and June 2018. In addition to this referral status, the study population was required to have confirmation of LVEF≤50% by CMR, no known CAD, no prior MI, and no CMR evidence of either prior ischemic injury or acute myocarditis. All underwent routine collection of patient demographics, comorbidities and symptom scores and standardized reporting using commercial software (Acuity, Cohesic Inc) followed by automated linkage to administrative databases for the collection of laboratory, pharmacy and ICD-10 coded clinical outcome data. Patients were followed for the combined endpoint of heart failure hospital admission or death. A multivariable cox proportional hazards model was developed and was used to establish a points-based risk score for prediction of the primary outcome ...
6. Stats: More than 90% censored values (April 22, 2005). Someone asked me about running a Cox proportional hazards regression model when over 90% of the observations were censored. That means (if the outcome of interest was death), that your research subjects did not cooperate and die fast enough. Good news from the patients perspective, but bad news for the statistician. 90% censored observations is not a problem, though, as long as your sample size is adequate. As a rough rule of thumb, you need to have 25 to 50 events (uncensored observations) in each treatment group to have reasonable precision. Of course, if you have fewer events, the model is still valid, but your confidence intervals may end up being wider than youd really like.. 5. Stats: Stratified Cox regression models (March 22, 2005). Someone sent me an email asking about a Cox regression model that included a strata for clinics. Whats the best way to handle strata? Thats a tricky question to answer. The first question you might ...
Cancer, Breast, Breast Cancer, Mortality, Recurrence, Risk, Diagnosis, Women, Association, Survivors, Survival, Associations, Cox Proportional Hazards Models, Hazards Models, Prognosis, Proportional Hazards Models, Health, Confidence Intervals, Recurrences, Physical Activity
Create the simplest test data set # test1 ,- list(time= c(4, 3,1,1,2,2,3), status=c(1,NA,1,0,1,1,0), x= c(0, 2,1,1,1,0,0), sex= c(0, 0,0,0,1,1,1)) coxph( Surv(time, status) ~ x + strata(sex), test1) #stratified model # # Create a simple data set for a time-dependent model # test2 ,- list(start=c(1, 2, 5, 2, 1, 7, 3, 4, 8, 8), stop =c(2, 3, 6, 7, 8, 9, 9, 9,14,17), event=c(1, 1, 1, 1, 1, 1, 1, 0, 0, 0), x =c(1, 0, 0, 1, 0, 1, 1, 1, 0, 0) ) summary( coxph( Surv(start, stop, event) ~ x, test2 ...
By adapting survival analysis on the staying at home of qualified recipients for long-term care, this paper attempts to empirically clarify what factors contribute to staying at home as long as possible. Using the National Health Insurance Services Long-Term Care Qualification Longitudinal Survey (2008-2015), this paper analyzed the factors contributing to the initial benefit selection and at-home survival rate. The results of the factor analysis showed that the probability of choosing home care was higher for males, lower age group, having family caregivers. On the other hand, in the case of dementia, the probability of choosing institutional care was high. As a result of the life table analysis, it was found that 13.1% of the initial home care users changed to institutional care, and about 71% of the moves take place between 2 and 4 years. The Cox proportional hazards regression model analysis showed that the likelihood of withdrawal from home care was higher: for women, for older, for those ...
By adapting survival analysis on the staying at home of qualified recipients for long-term care, this paper attempts to empirically clarify what factors contribute to staying at home as long as possible. Using the National Health Insurance Services Long-Term Care Qualification Longitudinal Survey (2008-2015), this paper analyzed the factors contributing to the initial benefit selection and at-home survival rate. The results of the factor analysis showed that the probability of choosing home care was higher for males, lower age group, having family caregivers. On the other hand, in the case of dementia, the probability of choosing institutional care was high. As a result of the life table analysis, it was found that 13.1% of the initial home care users changed to institutional care, and about 71% of the moves take place between 2 and 4 years. The Cox proportional hazards regression model analysis showed that the likelihood of withdrawal from home care was higher: for women, for older, for those ...
Two methods are given for the joint estimation of parameters in models for competing risks in survival analysis. In both cases Coxs proportional hazards regression model is fitted using a data duplication method. In principle either method can be used for any number of different failure types, assu …
IMPORTANCE The association between early exposure to animals and type 1 diabetes in childhood is not clear. OBJECTIVE To determine whether exposure to dogs during the first year of life is associated with the development of type 1 diabetes in childhood. DESIGN, SETTING, AND PARTICIPANTS A nationwide cohort study utilizing high-quality Swedish national demographic and health registers was conducted. A total of 840 593 children born in Sweden from January 1, 2001, to December 31, 2010, were evaluated. Type 1 diabetes was identified using diagnosis codes from hospitals and dispensed prescriptions of insulin. Cox proportional hazards regression models were used to assess the association between exposure to dogs and risk of type 1 diabetes in childhood. The possible association was further investigated by performing dose-response and breed group-specific analyses. The cohort was followed up until September 30, 2012. Data analysis was conducted from October 15, 2015, to February 8, 2017. EXPOSURES ...
A new study isuggests that people with atrial fibrillation who exercise have a reduced risk for cardiovascular disease and all-cause mortality.
In survival data analysis, the aim of fitting a Coxs proportional hazards (Coxs PH) model is to estimate the effect of covariates on the baseline hazard function. However, Coxs PH model makes a number of assumptions, which may be violated in many applications. Applying Coxs PH model without ensuring that its underlying assumptions are validated can lead to negative consequences on the resulting estimates. In this article, a generalization of the Coxs PH model in terms of the increment in cumulative hazard function taking a form similar to the Coxs PH model, with the extension that the increment in baseline cumulative hazard function is raised to a power function. The problem of parameter estimation for the parameters in that generalization of Coxs PH model will be solved using Bayesian inference. When the increment in cumulative hazard function is a gamma process, the likelihood has a semi-closed form, which allows posterior sampling to be carried out for the parameters, hence achieving ...
LB-371 The relationship between socioeconomic status (SES) and health has long been of interest to epidemiologists and social policy makers. We prospectively examined the association between SES and the risk of developing first primary cancers in the NIH-AARP Study, a cohort of 498,447 50-71 year olds without cancer at enrollment in 1995/96. We used highest attained education, reported at baseline, as a proxy for SES. During 5 years of follow-up, 34,955 cancers were identified in 8 state cancer registries. Cox proportional hazards models were utilized to estimate relative risks (RR) and 95% confidence intervals (95%CI) for subjects who did not complete high school compared to those with post-graduate education, stratified by sex. In age adjusted models, men with lower educational attainment had significantly increased risks of developing cancers of the lung (RR:4.27; 95% CI:3.64-5.00), head and neck (RR:1.88; 95%CI:1.38-2.58), esophagus (RR:3.34; 95% CI:2.13-5.23), stomach (RR:2.60; ...
We discuss causal mediation analyses for survival data and propose a new approach based on the additive hazards model. The emphasis is on a dynamic point of view, that is, understanding how the direct and indirect effects develop over time. Hence, importantly, we allow for a time varying mediator. To define direct and indirect effects in such a longitudinal survival setting we take an interventional approach (Didelez, 2018) where treatment is separated into one aspect affecting the mediator and a different aspect affecting survival. In general, this leads to a version of the nonparametric g-formula (Robins, 1986). In the present paper, we demonstrate that combining the g-formula with the additive hazards model and a sequential linear model for the mediator process results in simple and interpretable expressions for direct and indirect effects in terms of relative survival as well as cumulative hazards. Our results generalize and formalize the method of dynamic path analysis (Fosen, Ferkingstad, Borgan,
The findings also suggest that regardless of a persons level of fat mass, a higher level of muscle mass helps reduce the risk of death.
where X1, X2,...,Xp denote a set of p explanatory variables that help to form this hazard rate at time t.. The coefficients, βk1,βk2,...,βkp for k=1,2,... can be estimated using a maximum likelihood methodology. The results obtained can be interpreted in much the same way as the results for a Cox proportional hazards model. More specifically, a positive valued estimate for βkj would suggest that an increase in the value of the variable j increases the hazard rate associated with the occurrence of the cause specific outcome k (i.e. shortens the length of time until the event occurs). Similarly, a negative valued estimate for βkj would suggest that an increase in the value of variable j decreases the hazard rate associated with the occurrence of the cause specific outcome k (i.e. lengthens the time until occurrence of the event). The fitted model results along with their p-values are presented in Table 2. For all analyses, SAS software was used; p≤0.05 was considered statistically ...
Type 2 diabetes is increasing globally and in Asia. The purpose of this study was to examine the association of a fit-fat index (FFI) with diabetes incidence among Japanese men. In total 5,014 men aged 18-64 years old, who had an annual health check up with no history of major chronic disease at baseline from 2002 to 2009 were observed. CRF was estimated via cycle ergometry. Overall, 7.6% of the men developed diabetes. The mean follow-up period was 5.3 years. Hazard ratios, 95% confidence intervals and P trend for diabetes incidence were obtained using the Cox proportional hazards model while adjusting for confounding variables ...
Type 2 diabetes is increasing globally and in Asia. The purpose of this study was to examine the association of a fit-fat index (FFI) with diabetes incidence among Japanese men. In total 5,014 men aged 18-64 years old, who had an annual health check up with no history of major chronic disease at baseline from 2002 to 2009 were observed. CRF was estimated via cycle ergometry. Overall, 7.6% of the men developed diabetes. The mean follow-up period was 5.3 years. Hazard ratios, 95% confidence intervals and P trend for diabetes incidence were obtained using the Cox proportional hazards model while adjusting for confounding variables ...
The paper, titled Proportional hazards models based on biased samples and estimated selection probabilities, was published in Vol. 36, No. 1, 2008, pp. 111-127.. Unrepresentative samples are common in observational studies and often lead to biased parameter estimates. The authors propose a two-stage inverse-probability-of-selection weighted proportional hazards model, using weights estimated from auxiliary information on the sampling process. The estimation of the weights is explicitly incorporated into the inference procedures, which leads to gains in efficiency relative to existing methods that treat the weights as fixed. The method is widely applicable from epidemiologic to ecological studies. Through the proposed methods, Pan and Schaubel demonstrate that the increased failure risk associated with expanded criteria on donor kidneys is greatly underestimated by previous analyses which did not account for the inherent bias introduced by the acceptance/discard process.. Dr. Pan is an ...
Methods: A cohort of 517,996 Korean adults, who did not have liver cancer at baseline and attended a health screening including free thyroxine (FT4) and TSH, were followed for up to 16 years. High and low TSH and FT4 were defined as those above the upper bound of reference interval and those below the lower bound of reference interval of their corresponding reference intervals, respectively. Mortality information was ascertained through National Death Records. The adjusted HR (aHR) with 95% confidence interval (CI) were estimated using a Cox proportional hazard model. ...
The goal of this project is to develop an interactive, Web-based Prognostigram program for adult patients with newly diagnosed cancer. The prognostic program creates individualized survival curves based on the Cox Proportional Hazards model of survival data from Barnes-Jewish Hospital (BJH) Oncology Data Services (ODS) and SEER*Stat (National Cancer Institute, Surveillance, Epidemiology, and End Results Software package). This program also includes important comorbid health information. Patient and physician focus groups were held to explore the utility of the program. Overall, both groups felt the program was informative and easy to use. Specific suggestions for improvement were made ... Read the full Final Report.. ...
In a standard Cox model you assume that all subjects share the same hazard (which can vary as a function of time) except for a (multiplicative) effect of their covariates. This is the proportional hazard assumption,. $\lambda(t\mid X) = \lambda_0(t)\exp(X^T\beta),$. where $\lambda(t\mid X)$ is the hazard function for a subject with covariates $X$.. In a stratified model, you allow the baseline hazard to vary between strata, just like it would if you fitted separate models, but you restrict the effect of the covariates to be the same for each strata. For each subject in strata $i$, you have. $\lambda_i(t\mid X) = \lambda_{0i}(t)\exp(X^T\beta).$. Note that there is no $i$ on the $\beta$ vector. If you fit separate models for each straum, you would have. $\lambda_i(t\mid X) = \lambda_{0i}(t)\exp(X^T\beta_i),$. which is the most general model (of these three models).. ...
CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Likelihood based regression models, such as the normal linear regression model and the linear logistic model, assume a linear (or some other parametric) form for the covariate effects. We introduce the Local Scotinq procedure which replaces the liner form C Xjpj by a sum of smooth functions C Sj(Xj)a The Sj(.) s are unspecified functions that are estimated using scatterplot smoothers. The technique is applicable to any likelihood-based regression model: the class of Generalized Linear Models contains many of these. In this class, the Locul Scoring procedure replaces the linear predictor VI = C [email protected] by the additive predictor C ai ( hence, the name Generalized Additive Modeb. Local Scoring can also be applied to non-standard models like Coxs proportional hazards model for survival data. In a number of real data examples, the Local Scoring procedure proves to be useful in uncovering non-linear covariate effects. It has the
Results Three Cox proportional hazards models for prediction of 10-year recurrent vascular event risk were developed based on age and sex in addition to clinical parameters (model A), carotid ultrasound findings (model B) or both (model C). Clinical parameters were medical history, current smoking, systolic blood pressure and laboratory biomarkers. In a separate part of the dataset, the concordance statistic of model A was 0.68 (95% CI 0.64 to 0.71), compared to 0.64 (0.61 to 0.68) for model B and 0.68 (0.65 to 0.72) for model C. Goodness-of-fit and calibration of model A were adequate, also in separate subgroups of patients having coronary, cerebrovascular, peripheral artery or aneurysmal disease. Model A predicted ,20% risk in 59% of patients, 20-30% risk in 19% and ,30% risk in 23%.. ...
get file =C:Dataasa2gbcs.sav. compute hormonexnodes = (hormone-1)*nodes. exe. coxreg rectime with nodes hormone hormonexnodes /status=censrec(1) /method = enter hormone nodes hormonexnodes /print = corr. data list free /nodes. begin data 0 1 3 5 7 9 10 15 20 25 30 35 40 45 50 end data. *Creating the variance and covariance matrix. compute #vn = .008**2. compute #vh = .164**2. compute #vhxn = .015**2. compute #cov_n_h = .291*sqrt((#vn)*(#vh)). compute #cov_n_hxn =-.529*sqrt((#vn)*(#vhxn)). compute #cov_h_hxn =-.643*sqrt((#vh)*(#vhxn)). compute log_hr = -.606 + nodes*(.038). compute se = sqrt(#vh + nodes**2*(#vhxn) + 2*nodes*#cov_h_hxn). compute log_hr_l = log_hr - 1.96*se. compute log_hr_u = log_hr + 1.96*se. exe. graph /scatterplot(overlay) = nodes nodes nodes with log_hr log_hr_l log_hr_u (pair). ...
Concepts, models and techniques in survival analysis including types of censoring and truncation, Kaplan-Meier estimators, log-rank statistics, parametric models, proportional hazards models, extended PH models, competing risks, recurrent events and frailty models ...
The generic term parametric proportional hazards models can be used to describe proportional hazards models in which the hazard ... Proportional hazards models are a class of survival models in statistics. Survival models relate the time that passes, before ... For example, assuming the hazard function to be the Weibull hazard function gives the Weibull proportional hazards model. ... hazards models and Poisson regression models which is sometimes used to fit approximate proportional hazards models in software ...
... and for some non-linear regression models. Other non-linear models, such as proportional hazards models for survival analysis, ... Hughes, M. D. (1993). "Regression dilution in the proportional hazards model". Biometrics. 49 (4): 1056-1066. doi:10.2307/ ... derived either directly by observation-with-error or from application of a measurement model, such as the Rasch model. Also, ... The case that x is fixed, but measured with noise, is known as the functional model or functional relationship. It can be ...
The Cox model assumes that the hazards are proportional. The proportional hazard assumption may be tested using the R function ... For quantitative predictor variables, an alternative method is Cox proportional hazards regression analysis. Cox PH models work ... Cox models may be extended for such time-varying covariates. The Cox PH regression model is a linear model. It is similar to ... Tree-structured survival models may give more accurate predictions than Cox models. Examining both types of models for a given ...
Such models are generally classed proportional hazards regression models; the best known being the Cox proportional hazards ... Survival analysis Failure rate and Hazard rate Proportional hazards models Relative risk Najjar-Debbiny, R.; Gronich, N.; Weber ... If the proportional hazard assumption holds, a hazard ratio of one means equivalence in the hazard rate of the two groups, ... Regression models are used to obtain hazard ratios and their confidence intervals. The instantaneous hazard rate is the limit ...
"On the Use of the Accelerated Failure Time Model as an Alternative to the Proportional Hazards Model in the Treatment of Time ... Patel, K; Kay, R; Rowell, L (2006). "Comparing proportional hazards and accelerated failure time models: an application in ... Simino, J.; Hollander, M.; McGee, D. (2012). "Calibration of Proportional Hazards and Accelerated Failure Time Models". ... In most toxicological models, the effect is proportional to concentration of toxin or amount of insult. However, in the AFT ...
Van Den Poel; Lariviére (2004). "Customer Attrition Analysis For Financial Services Using Proportional Hazard Models". European ... Several studies combine several different types of predictors to develop a churn model. This model can take demographic ... Since these models generate a small prioritized list of potential defectors, they are effective at focusing customer retention ... One of the main objectives of modeling customer churn is to determine the causal factors, so that the company can try to ...
"Customer attrition analysis for financial services using proportional hazard models". European Journal of Operational Research ... A principal danger of such data redundancy is that of overfitting in regression analysis models. The best regression models are ... Such a model is often called "low noise" and will be statistically robust (that is, it will predict reliably across numerous ... More importantly, the usual use of regression is to take coefficients from the model and then apply them to other data. Since ...
If the sample consists of right censored data and the model to use is Hypertabastic proportional hazards model, then, the ... Hypertabastic Proportional Hazards Model with Log Time */ title1 'Kidney Carcinoma'; max logf; /* Model Parameter Initial ... was performed using the generalized chi-square test statistics and proportional hazards model. The Hypertabastic proportional ... The Hypertabastic proportional hazards model was used to analyze the survival time of patients diagnosed with kidney carcinoma ...
Survival analysis includes Cox regression (Proportional hazards model) and Kaplan-Meier survival analysis. Procedures for ...
... that would be the proportional hazards model. Unlike proportional hazards models, in which Cox's semi-parametric proportional ... AFT model) is a parametric model that provides an alternative to the commonly used proportional hazards models. Whereas a ... Unlike proportional hazards models, the regression parameter estimates from AFT models are robust to omitted covariates. They ... proportional hazards model assumes that the effect of a covariate is to multiply the hazard by some constant, an AFT model ...
These models often use smoothing or kernels. A well-known example of a semiparametric model is the Cox proportional hazards ... a semiparametric model is a statistical model that has parametric and nonparametric components. A statistical model is a ... However, a semiparametric model is considered to be "smaller" than a completely nonparametric model because we are often ... It may appear at first that semiparametric models include nonparametric models, since they have an infinite-dimensional as well ...
"Methods for the Analysis of Sampled Cohort Data in the Cox Proportional Hazards Model" (PDF). Annals of Statistics. 23 (5): ... The analysis of a nested case-control model must take into account the way in which controls are sampled from the cohort. ... Since the covariate is not measured for all participants, the nested case-control model is both less expensive than a full ...
An example of the use of the proportional hazards model is in survival analysis in medical research. The model can be used in ... The proportional hazards model, which is widely used in the analysis of survival data, was developed by him in 1972. ... the proportional hazards model and the Cox process, a point process named after him. He was a professor of statistics at ... "the development of the Proportional Hazard Regression Model." In 2010 he was awarded the Copley Medal of the Royal Society "for ...
... parametric survival models and the Cox proportional hazards model may be useful to estimate covariate-adjusted survival. The ... Both are based on rewriting the survival function in terms of what is sometimes called hazard, or mortality rates. However, ... "sts - Generate, graph, list, and test the survivor and cumulative hazard functions" (PDF). Stata Manual. Cleves, Mario (2008). ... Kaplan-Meier estimator can be derived from maximum likelihood estimation of hazard function.[self-published source?] More ...
These estimators range from fully parametric models such as the Mixed Proportional Hazard model, to nonparametric and ... Salant shows that heterogeneity in hazard rates between the stock and the flow distribution provides a key to understanding why ... Hausman, J. A. and T. Woutersen (2014), Estimating a semi-parametric duration model without specifying heterogeneity. Journal ...
The logrank statistic can be derived as the score test for the Cox proportional hazards model comparing two groups. It is ... assume the hazard functions in the two groups are proportional with hazard ratio λ {\displaystyle \lambda } and d 1 {\ ... If the hazard ratio is λ {\displaystyle \lambda } , there are n {\displaystyle n} total subjects, d {\displaystyle d} is the ... The logrank test statistic compares estimates of the hazard functions of the two groups at each observed event time. It is ...
Meller Grambsch is an American biostatistician known for her work on survival models including proportional hazards models. She ... With Terry M. Therneau, Grambsch is the author of the book Modeling Survival Data: Extending the Cox Model (Statistics for ... retrieved 2020-06-20 Reviews of Modeling Survival Data: Broström, Göran, zbMATH, Zbl 0958.62094{{citation}}: CS1 maint: ...
... creates proportional hazards models, one class of survival analysis: see proportional hazards models for ... Other generalized linear models such as the negative binomial model or zero-inflated model may function better in these cases. ... A Poisson regression model is sometimes known as a log-linear model, especially when used to model contingency tables. Negative ... This model is popular because it models the Poisson heterogeneity with a gamma distribution. Poisson regression models are ...
Kaplan-Meier estimators and Cox proportional hazards models for time to coronary heart disease after receipt of hormone ... Vonesh, Edward F.; Chinchilli, Vernon G. (1997). "Crossover Experiments". Linear and Nonlinear Models for the Analysis of ...
Cox Proportional Hazards Regression Analysis as a Modeling Technique for Informing Program Improvement: Predicting Recidivism ... The Teaching-Family Model (TFM) is a model of care for persons in need of services and care necessary to support an improved ... The Teaching-Family Model has been suggested as a model program for residential treatment facility and behavior modification ... The model has been replicated over 800 times, although not all of the replications have proven effective and successful. This ...
Her work in this time on the graft-versus-tumor effect become "the first major application of the proportional hazards model ... for serving as a role model and mentor for graduate students and young faculty; for her scholarship in teaching and research, ...
... mathematical statistician whose research topics include missing data in longitudinal studies and proportional hazards models. ... "Role models needed for women students, says new prof", Update!, St. Jerome's College, vol. 5, no. 2, p. 7, Fall 1985, retrieved ...
... proportional hazards models, and M-estimators. Given the objective function 1 N ∑ i = 1 N f ( x i , y i , α , β ) {\ ... proportional hazards models, and M-estimators. Lasso's ability to perform subset selection relies on the form of the constraint ... lasso regularization is easily extended to other statistical models including generalized linear models, generalized estimating ... This can be modeled using the following regularization: ∑ i < j p , β i − β j , ≤ t 2 . {\displaystyle \sum _{i. < p < 1 {\ ...
A proportional hazards regression model was used for each cancer type with the cancer as the outcome and PFOA serum level ... Office of Environmental Health Hazard Assessment, Cancer Toxicology and Epidemiology Section, Reproductive and Cancer Hazard ... Models were adjusted for time-varying- smoking and alcohol consumption, as well as sex, education and five-year birth cohort. ... hazard ratio = 1.10 and 1.34, respectively, for a 1-unit increase in log-transformed serum PFOA]. The study consisted of 32,254 ...
An Analysis Based on the Proportional Hazards Model." Journal of Animal Ecology. 54 (3). Coombs, E. M., et al., Eds. (2004). ...
An Analysis Based on the Proportional Hazards Model."Journal of Animal Ecology, Vol. 54, No. 3 (Oct., 1985). Helantera, Heikki ... F. polyctena is consistent with this model, with almost completely sterile workers that do not lay eggs. This is in contrast to ... Aubert and Richard proposed this social vaccination model, where they argue that if fellow nestmates groom an infected ant, ...
It is a key component of the proportional hazards model: using a restriction on the hazard function, the likelihood does not ... of a model, given an event, is the negative of the surprisal of the event, given the model: a model is supported by an event to ... That is, a model that does not meet these regularity conditions may or may not have a maximum likelihood estimator of the ... Due to the introduction of a probability structure on the parameter space or on the collection of models, it is possible that a ...
Survival analysis Proportional hazards models Redner 2001 Bachelier 1900 Von E 1900 Smoluchowski 1915 Lundberg 1903 Tweedie ... Lee, M.-L. T.; Whitmore, G. A. (2010). "Threshold Proportional hazards and threshold regression: their theoretical and ... The model considers the event that the amount of money reaches 0, representing bankruptcy. The model can answer questions such ... In statistics, first-hitting-time models are a sub-class of survival models. The first hitting time, also called first passage ...
... proportional hazard models). The compensation law of mortality also represents a great challenge for many theories of aging and ... PMID 111909 Gavrilov, L.A. "A mathematical model of the aging of animals". Doklady Akademii Nauk SSSR, 1978, 238(2): 490-492. ...
McCall, B. P. (1994): Testing the Proportional Hazards Assumption in the Presence of Unmeasured Heterogeneity. Journal of ... and it enters the hazard function multiplicatively. One can define the conditional hazard as the hazard function conditional on ... It then follows that the average hazard is given by exp(x'β) αtα-1. More generally, it can be shown that as long as the hazard ... and the hazard function λ(.). Recent examples provide a nonparametric approaches to estimating the baseline hazard and the ...
These features have been compared to similar aspects of the earlier Chinese model. In the British civil service, just as it was ... in numbers roughly proportional to each province's population. Elite individuals all over China, even in the disadvantaged ... over birth and allow for dramatic social mobility was most attractive for contemporary Europeans in the grip of the hazards of ... With the disappearance of the old aristocracy, Wu's system of bureaucrat recruitment once more became the dominant model in ...
The former tends as the cube of the bubble's radius while the latter is proportional to the square of its radius, so there is a ... Ellis, J.; Espinosa, J.R.; Giudice, G.F.; Hoecker, A.; Riotto, A. (2009). "The Probable Fate of the Standard Model". Phys. Lett ... Space hazards, Ultimate fate of the universe, Vacuum). ... Nonetheless, new physics beyond the Standard Model of Particle ... Salvio, Alberto (2015-04-09). "A Simple Motivated Completion of the Standard Model below the Planck Scale: Axions and Right- ...
The hazards posed by a capacitor are usually determined, foremost, by the amount of energy stored, which is the cause of things ... The simplest model of a capacitor consists of two thin parallel conductive plates each with an area of A {\displaystyle A} ... Thus the charge on the electrodes is equal to the integral of the current as well as proportional to the voltage, as discussed ... This model applies well to many practical capacitors which are constructed of metal sheets separated by a thin layer of ...
Models developed in 2018 to explain the unusual spin of Uranus support a long-held theory that this was caused by an oblique ... Melosh, H. J. (2003). "Impact-generated tsunamis: An over-rated hazard". Lunar and Planetary Science Conference Abstract. 34: ... which is on average proportional to the diameter of the impactor. Asteroids with a 1 km (0.62 mi) diameter strike Earth every ... Computer modelling suggests that the impact involved large asteroids or protoplanets similar to the events believed to have led ...
AFGRL developed the Klobuchar model for computing ionospheric corrections to GPS location. Of note is work done by Australian ... the time delay between when the satellite transmits a signal and the ground station receives it is proportional to the distance ... GPS can be used to measure crustal motion and deformation to estimate seismic strain buildup for creating seismic hazard maps. ... longitude and height relative to an ellipsoidal Earth model. The height may then be further converted to height relative to the ...
Cox, K. G. (1 November 1980). "A Model for Flood Basalt Vulcanism". Journal of Petrology. 21 (4): 629-650. doi:10.1093/ ... The lateral extent of a flood basalt flow is roughly proportional to the cube of the thickness of the flow near its source. ... Geological hazards, Future problems, Doomsday scenarios). ... "A new model for the emplacement of Columbia River basalts as ...
... has more hazards and greater risk than basic open water diving. Nitrogen narcosis, the "narks" or "rapture of the ... Using normal scuba equipment, breathing gas consumption is proportional to ambient pressure-so at 50 metres (160 ft), where the ... model, a two-stage regulator (patented by Novelli and Buggiani) equipped with a lung bag and soda lime filter for CO2 removal, ... Nitrogen narcosis becomes a hazard below 30 metres (98 ft) and hypoxic breathing gas is required below 60 metres (200 ft) to ...
Light from a near-IR laser may thus appear dim red and can present a hazard since it may actually be quite bright. And even IR ... Jones, B.S.; Lynn, W.F.; Stone, M.O. (2001). "Thermal Modeling of Snake Infrared Reception: Evidence for Limited Detection ... 1879: Stefan-Boltzmann law formulated empirically that the power radiated by a blackbody is proportional to T4. 1880s and 1890s ... Thermal infrared radiation also has a maximum emission wavelength, which is inversely proportional to the absolute temperature ...
The LNT model is sometimes applied to other cancer hazards such as polychlorinated biphenyls in drinking water. The association ... response model in which the risk of inducing a cancer in an irradiated tissue by low doses of radiation is proportional to the ... The validity of the LNT model, however, is disputed, and three other significant models exist: the threshold model, which ... The LNT model has been contested by a number of scientists. It has been claimed that the early proponent of the model Hermann ...
With sufficient power, this could be a hazard to people near the cable. A properly placed and properly sized balun can prevent ... Coaxial cable is a particular kind of transmission line, so the circuit models developed for general transmission lines are ... The outer diameter is roughly inversely proportional to the cutoff frequency. A propagating surface-wave mode that only ... with the depth of penetration being proportional to the square root of the resistivity. This means that, in a shield of finite ...
The food addiction model asserts that excessive consumption of palatable foods may be understood within the same ... Mishra, MB; Mishra, Shanu (2011-01-01). "Sugar-Sweetened Beverages: General and Oral Health Hazards in Children and Adolescents ... increase in sugar-sweetened beverage taxes would result in proportional reduction in consumption. Other solutions target ... model of overweight". Appetite. 114: 64-72. doi:10.1016/j.appet.2017.03.024. hdl:1983/699cf0f2-1344-4414-bd84-0cf80c0feff5. ...
Natural hazards and generation/consumption imbalances are a major cause of concern. To minimize the probability of grid ... System operations staff undertake this work using sophisticated energy modelling and communications systems. In addition to its ... They are financed either by the states or countries or by charging a toll proportional to the energy they carry. The system ...
... as reverse-engineered by ProPublica using logistic regression and Cox's proportional hazard model. Hastie, T. J.; Tibshirani, R ... is estimated using a generalized linear model: E ⁡ ( Y , X ) = P ( Y = 1 , X ) = g − 1 ( X β ) {\displaystyle {\begin{aligned}\ ... J. (1990). Generalized Additive Models. Chapman & Hall/CRC. ISBN 978-0-412-34390-2. Toren, Yizhar (2011). "Ordinal Risk-Group ...
Rock fall would affect the area close to the summit domes, as would pyroclastic flows; these would be a further hazard to the ... and the proportional amount of fresh volcanic material increased at first; since 1997 discontinuous eruptions generate steam ... "Geomorphologic map and derived geomorphological evolution model of the Ampato volcanic complex (Southern Peru)". EGU General ... Annen, Catherine; Wagner, Jean-Jacques (2003-11-01). "The Impact of Volcanic Eruptions During the 1990s". Natural Hazards ...
Most of the hazards to which the standard diver was exposed are much the same as those to which any other surface supplied ... No-bolt model used similar rubber flange to 3-bolt helmets, but clamped between the bonnet and corselet which were connected at ... which was proportional to the depth at which the diver worked.[citation needed] Umbilical: A diver's umbilical is a cable made ... Later models were equipped with a diver's telephone for voice communications with the surface. The term deep sea diving was ...
A hazard is any agent or situation that poses a level of threat to life, health, property, or environment. Most hazards remain ... Some models require a bailout block to provide alternative breathing gas supply from the umbilical and bailout cylinder, but ... and the weight is directly proportional to the total volume - smaller helmets are lighter. To avoid fatigue, divers avoid ... or the combined probability of undesirable consequences of all the hazards of a specific activity. A hazard that is understood ...
The UV index is designed as an open-ended linear scale, directly proportional to the intensity of UV radiation that causes ... Predictions are made by a computer model that accounts for the effects of sun-earth distance, solar zenith angle, total ozone ... Hazard scales). ... reports is usually a prediction based on a computer model. ...
These advanced models cost somewhat more but are otherwise similar to the basic models. The digital models offer the advantage ... A biomimetic sensor works in a fashion similar to hemoglobin which darkens in the presence of CO proportional to the amount of ... They will warn the driver and passenger if there is a CO hazard. Another type is used by industrial hygienists and first ... Newer models are designed to signal a need to be replaced after a set time span. CO detectors all have "test" buttons like ...
For logistic regression or Cox proportional hazards models, there are a variety of rules of thumb (e.g. 5-9, 10 and 10-15 - the ... The book Model Selection and Model Averaging (2008) puts it this way. Given a data set, you can fit thousands of models at the ... An under-fitted model is a model where some parameters or terms that would appear in a correctly specified model are missing. ... Model Selection and Model Averaging, Cambridge University Press. Harrell, F. E. Jr. (2001), Regression Modeling Strategies, ...
There is no unifying theory or model for determining or managing water risk.: 13 Instead, a range of theories, models, and ... Water security risks in Bangladesh include:: 45 some natural hazards that related to climate (climate hazards) the impacts of ... 140 Water scarcity and water security do not have to be directly proportional: There are regions with high water security, ... For example, the long rains in East Africa which fall March to May have been difficult to simulate within the climate models ...
In Drive Mobile, a steering wheel was used to control a model car over a road painted on a metal drum, with the goal being to ... The gameplay itself can be of any arcade game, and the number of tickets received are proportional to the player's score. Skee ... Cabot, Anthony N.; Light, Glenn J.; Rutledge, Karl F. (2009). "Alex Rodriguez, a Monkey, and the Game of Scrabble: The Hazard ... with later arcade systems such as the Sega Model 3 remaining considerably more advanced than home systems through the late ...
doi:10.1016/s0262-4079(07)61866-1. Mone, Gregory (April 2014). "New Models in Cosmetics Replacing Animal Testing". ... the acceptability of this to opponents of testing is inversely proportional to how recent the data is. Methods of testing ... repeated oral force-feeding studies lasting weeks or months to look for signs of general illness or specific health hazards, ... research companies such as NOTOX have developed a synthetic model of the human liver, which is the main organ to detox the body ...
For modelling the effect of static discharge on sensitive electronic devices, a human being is represented as a capacitor of ... As little as 0.2 millijoules may present an ignition hazard; such low spark energy is often below the threshold of human visual ... and can be roughly proportional to particulate flow. Dust clouds of finely powdered substances can become combustible or ... This is not considered to be a hazard for dust clouds. Propagating brush discharge is high in energy and dangerous. Occurs when ...
red tide reduced gradient bubble model A computationally intensive bubble model decompression algorithm developed by Bruce ... pressure transducer A component that produces a signal proportional to a pressure input, which can be processed to give an ... element Item of equipment or process with the purpose to prevent or limit the consequences of a high risk hazard, that if ... perfusion limited The assumption in a decompression model that perfusion has the dominant influence on gas uptake and release. ...
One of these later models was the Seatec Manta, with shoulder buckles and a softpac structure (without a rigid backpack) In ... The buoyancy compensator is both an important safety device when used correctly, and a significant hazard when misused or ... The depth range in which effectively stable neutral buoyancy can be maintained is inversely proportional to the volume of ... Most BCs do not have a CO2 inflation option, which eliminates this hazard. Redundant bladders may be inadvertently filled, ...
... so global climate modelling makes use of ocean circulation models as well as models of other major components such as the ... Homer describes the ten-year voyage of the Greek hero Odysseus who struggles to return home across the sea's many hazards after ... radiating outwards at a velocity proportional to the square root of the depth of the water and which therefore travels much ... Ocean models make use of a branch of physics, geophysical fluid dynamics, that describes the large-scale flow of fluids such as ...
A model of a city in which each district has its own distribution of buildings into classes and its population, is far superior ... This is so because the surface wave M, which is quickly obtained, is defined as proportional to the 20 sec Reighly surface wave ... Such calculations are similar to those made to assess the seismic hazard, part of the field of engineering seismology. Errors ... A cost-effective way to model a large city is to treat each administrative district as a separate settlement. In many large ...
An alternative model for bedrock erosion is the unit stream power, which assumes that erosion rates are proportional to the ... Natural Hazards and Earth System Sciences. 15: 225-245. doi:10.5194/nhess-15-225-2015. ISSN 1561-8633. Poesen, Jean; Lavee, ... The most commonly used model for predicting soil loss from water erosion is the Universal Soil Loss Equation (USLE) (also known ... Bosco, Claudio; de Rigo, Daniele; Dewitte, Olivier; Poesen, Jean; Panagos, Panos (2015). "Modelling soil erosion at European ...
The Cox proportional hazards model is one such method that is widely used. As more extensions of the Cox model with time- ... Hendry, David J. (2013) Data generation for the Cox proportional hazards model with time-dependent covariates: A method for ... This paper develops a method for the generation of survival times that follow a Cox proportional hazards model with time- ... Data generation for the Cox proportional hazards model with time-dependent covariates: A method for medical researchers ...
... model. We compare and contrast this model with the mixed proportional hazard (MPH) model, which continues to be the workhorse ... model. We compare and contrast this model with the mixed proportional hazard (MPH) model, which continues to be the workhorse ... model. We compare and contrast this model with the mixed proportional hazard (MPH) model, which continues to be the workhorse ... model. We compare and contrast this model with the mixed proportional hazard (MPH) model, which continues to be the workhorse ...
... in a proportional hazards regression analysis was evaluated using Monte Carlo simulation techniques for data from a randomized ... large sample properties did not hold for variance estimates from the proportional hazards model, and the Z statistics used to ... the results of proportional hazards regression analyses should be interpreted with caution because the statistical model may ... The analytical effect of the number of events per variable (EPV) in a proportional hazards regression analysis was evaluated ...
Survival analysis: Cox proportional hazards model. National Medical Journal of India. 1999 Sep-Oct; 12(5): 230-3. ...
Results: Cox Proportional Hazards Model. Finally, I generated a Cox Proportional Hazards Model to further look at the second ... In relation to the second hypothesis, the Cox Proportional Hazards Model in Table 3 (net all control variables) shows that, in ... In relation to the third hypothesis, the Cox Proportional Hazards Model in Table 3 (net all control variables), shows that an ... Relate results in the Cox Proportional Hazards model will be discussed further in that section. These results support the ...
Coxs proportional hazards model. The Coxs proportional hazards model was used as an alternative method for evaluating ... Results from the Coxs proportional hazards models were similar to the results of Poisson regression models. For example, the ... Proportional hazards models were fitted with the SAS procedure PHREG10 configured for a matched logistic regression analysis ... POISSON REGRESSION ANALYSES AND COXS PROPORTIONAL HAZARDS MODEL. Table 1 and figure 1 show the results of fitting the Poisson ...
Multivariate Cox proportional hazard model evaluating risk factors for patient survival Multivariate Cox proportional hazard ... hazard ratio; LRT, likelihood ratio test; MVA, motor vehicle accident; NAT, nucleic acid test; SIDS, sudden infant death ...
... proportional hazards models ... Cox models yielded estimates of adjusted hazard ratios, with ... and results for splined exposures generally reflected their categorically modeled counterparts. We found significantly ...
Proportional Hazards Models. EN. dc.subject. Quality Control. EN. dc.subject. Risk Assessment. EN. ... Application of hazard analysis and critical control point system in the dairy industry. Kassem, M.. ... Application of hazard analysis and critical control point system in the dairy industry. EN. ... and dairy products before and after application of a hazard analysis and critical control point [‎HACCP]‎ system at a milk and ...
Modelling techniques varied, the most popular being Cox proportional hazards regression and hierarchical clustering which were ... Research into a predictive, as opposed to prognostic, model could be highly beneficial and aid the identification of the most ... 42 studies were identified and both the data collection and modelling methods were compared. The majority of studies utilised ... Cox proportional hazards models. When studies identified by this review applied the Cox proportional hazards model to predict ...
The Cox proportional hazards model has been a common choice in analysing data to understand factors strongly associated with ... Random survival forests and the Cox proportional hazards model agree that the sex of the household head, sex of the child, ... However, due to its restrictive proportional hazards (PH) assumption, some covariates of interest which do not satisfy the ... Thus the first part of the analysis is based on the use of the classical Cox PH model and the second part of the analysis is ...
... hazard ratio, HR = 1.29-1.39, p , 0.05). Rosuvastatin was the most preferred lipid-lowering medicine with lower HRs of reHospIS ... and characteristics of the first hospitalization due to IS were all adjusted in models. Moreover, increasing trends of HRs of ... hazard ratio, HR = 1.29-1.39, p , 0.05). Rosuvastatin was the most preferred lipid-lowering medicine with lower HRs of reHospIS ... and characteristics of first hospitalization due to IS were all adjusted in models. Moreover, increasing trends of HRs of ...
In this secondary analysis, the effect of ECPR on 180-day survival using Kaplan-Meier estimates and Cox proportional hazard ... model was examined. Among 256 patients (median age 58 years, 83% male) with median duration of resuscitation 52.5 min ... Cox proportional hazards model of 180-day survival. After adjusting for the most important covariates in the Cox proportional ... Table 3 The Cox proportional hazards model for 180-day mortality. Full size table. ...
Cox proportional hazards models were utilised for univariate and multivariate analyses. The HR with 95% CI and P values were ...
Analyses were performed with Cox proportional hazard models by which hazard ratios and 95% confidence intervals were calculated ... The statistical analyses were performed using the Cox proportional hazard models for the estimation of hazard ratio (HR) and 95 ... Analyses were performed with Cox proportional hazard models by which hazard ratios and 95% confidence intervals were calculated ... Model A shows the estimates adjusted for age and gender while Model B further adjusts for socioeconomic status (education, ...
Evaluating bias from birth cohort effects in the age-based Cox proportional hazards model. Epidemiology 2011;22:249-56. ... Initial analyses using continuous exposure-response models were based on power models (ie, log-linear models using a log- ... are identical to those from Cox proportional hazards regression. Hazard ratios (HRs) for lung cancer mortality were estimated ... Final models were checked for proportionality of hazards with age by evaluating its product with each exposure metric as an ...
Grambsch PM (1995) Goodness-of-fit and diagnostics for proportional hazards regression models. Cancer Treat Res 75:95-112 ... The proportional hazards assumption was assessed by examining log-log plots [29], and was met in each model. ... Cox proportional hazards regression was used to compute HRs and 95% CIs for associations between gestational age at birth and ... In the stratified Cox model, each set of siblings had its own baseline hazard function that reflects the familys shared ...
Assessing the assumptions of Cox proportional hazards regression models. Practical: Stratified Cox proportional hazards models ... Lecture: Introduction to Cox proportional hazards regression models. Practical: Fitting a Cox model in Stata. ... Practical: Fitting a multiple linear regression model. Linear Models 3. Lecture: Analysis of covariance and model assumptions. ... Generalized Linear Models. Lecture: Introduction to common Generalized Linear Models. Practical: Poisson regression and glm. ...
... and differences between two groups were compared using the log-rank test and Cox proportional hazards regression models. A ... Table 5 lists the results of proportional hazards regression analysis used to test the predictive value of each variable for OS ... In this multivariate model adjusted for age, ECOG PS, and the presence of visceral metastases, vaccination therapy was an ... "Dendritic cell immunotherapy combined with gemcitabine chemotherapy enhances survival in a murine model of pancreatic carcinoma ...
Proportional hazards frailty models for recurrent methadone maintenance treatment. Am J Epidemiol 2009;170:783-92. ... Model design. We developed a decision-analytical model to capture the cycles of treatment, relapse and abstinence observed in ... Dynamics of the cohort model. All patients entered the model in a treatment state (diacetylmorphine or methadone maintenance ... we derived model parameters from the trial data where possible. When trial data were not available to populate model parameters ...
Survival Analysis Using the Proportional Hazards Model 3 Intermediate. Advanced Statistical Modeling Using the NLMIXED ... Managing Models in SAS Viya 3 Intermediate. Managing SAS Analytical Models Using SAS Model Manager Version 14.2 3 Intermediate ... Credit Risk Modeling 3 Intermediate. Risk Modeling Add-on for SAS Visual Machine Learning: Using Credit Scoring Nodes 3 ... Predictive Modeling Using Logistic Regression 4 Expert. Predictive Modeling Using SAS High-Performance Analytics Procedures 4 ...
... variables and the proportional hazards model. BIOS 765 Research Design in the Biomedical Sciences. (3) (Prereq: BIOS 757) ( ... frailty model, competing risk model and multi-state model. Techniques motivated by applications in epidemiology and clinical ... Encompasses logistic and other binary regressions, log-linear models, and gamma regression models. ... BIOS 815 Generalized Linear Models [=STAT 775] (3) (Prereq: STAT 713 or STAT 513, and STAT 705 or BIOS 757. Statistical theory ...
HRs and 95% CIs were estimated from multivariate Cox proportional hazards models. RESULTS: Most patients who received a ...
Proportional Hazards Models. Survival Rate. Kaplan-Meier Estimate. Medical Oncology. Research Design. Randomized Controlled ...
Multivariable-adjusted Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals ( ... Multi-adjusted Cox proportional hazards models were computed. A higher FSAm-NPS DI score, reflecting a lower nutritional ... model in the Bulgarian context, with the potential to help consumers better understand the nutritional quality of. food. The ... regression models within and across food categories were fit.. Results : Compared with the Reference Intakes group, ...
A proportional hazards model for sub distribution of a competing risk. J Am Stat Assoc. 1999; 94:496-509.. * Cited Here , ... 22 Multivariate analysis was performed using a Cox proportional-hazards model which included variables differing significantly ... Results were expressed as the hazard ratio (HR) with a 95% confidence interval (95% CI). All tests were 2-sided with a type 1 ... hazard ratio [HR] = 0.56; P = 0.14), respectively. By multivariate analysis, relapse incidence, and leukemia-free survival were ...
Here we will focus on the Cox proportional hazards model using a model fitted on our dose-age data that we described above: . ... and gamma models. In the case of the Cox proportional hazards model, ... The robust inference of the Cox proportional hazards model. Journal of the American Statistical Association 84: 1074-1078. ... baseline hazard (and stratified baseline hazard if estimates are stratified) *cumulative baseline hazard *baseline survivor ...
Schoenfeld D. Partial residuals for the proportional hazards model. Biometrika. 1982;69:51-55. ... Without adjustments, the Cox proportional hazards model analysis indicates that increased serum transferrin saturation did not ... We performed Cox proportional hazards analysis with cancer event time for each group, controlling for age, sex, race, smoking ... The results of the Schoenfeld analysis indicated that the hazards were proportional. No significant interaction was found in ...
  • The risk of reHospIS was assessed using Cox proportional hazards regression model. (
  • After adjusting for sex, age and frailty, in-hospital mortality did not significantly differ between transplant and dialysis patients [hazard ratio (HR) 0.81, 95% CI 0.59-1.10, P = 0.18]. (
  • We compare hazard ratio estimates for effect of an aggressive treatment regimen from Cox proportional hazards models using time to initial treatment outcome, predicted vital status, and true vital status at the end of the cohort period. (
  • A study by Moss et al found that in patients with KCNQ1 mutations, the Cox proportional hazards survivorship model indicated an increased risk for cardiac events in patients with transmembrane versus C-terminus mutations (hazard ratio, 2.06), as well as in patients with mutations resulting in dominant-negative versus haploinsufficiency ion channel effects (hazard ratio, 2.26). (
  • Cox regression model was used to calculate the hazard ratio (HR).A count of 314 cases (3.4%) of hypoparathyroidism was identified. (
  • Further multivariable analysis revealed a proportional hazard ratio (HR) for disease-free survival rate of 1.87 (95% CI: 1.04-3.37 pâ ¯=â ¯0.036). (
  • Groups were compared through a multivariable Cox proportional Hazards model. (
  • Prediction models were developed in UKB using multivariable Cox proportional hazards regression for circulatory mortality, incident stroke and MI, and externally validated in EPIC-Norfolk. (
  • As more extensions of the Cox model with time-dependent covariates are developed, simulations studies will grow in importance as well. (
  • This paper develops a method for the generation of survival times that follow a Cox proportional hazards model with time-dependent covariates. (
  • However, due to its restrictive proportional hazards (PH) assumption, some covariates of interest which do not satisfy the assumption are often excluded in the analysis to avoid mis-specifying the model. (
  • Thus the first part of the analysis is based on the use of the classical Cox PH model and the second part of the analysis is based on the use of random survival forests in the presence of covariates that do not necessarily satisfy the PH assumption. (
  • Random survival forests and the Cox proportional hazards model agree that the sex of the household head, sex of the child, number of births in the past 1 year are strongly associated to under-five child mortality in Uganda given all the three covariates satisfy the PH assumption. (
  • Random survival forests are appealing methods in analysing public health data to understand factors strongly associated with under-five child mortality rates especially in the presence of covariates that violate the proportional hazards assumption. (
  • Analysis of the Proportional Hazards Model with Sparse Longitudinal Covariates. (
  • Time-varying Cox proportional hazard regression models were used to estimate hazard ratios (HRs) for all-cause and cause-specific CVDs associated with PM2.5, adjusting for conventional covariates. (
  • Analyses were performed with Cox proportional hazard models by which hazard ratios and 95% confidence intervals were calculated. (
  • Hazard ratios and 95% confidence intervals for associations with 10-year breast cancer-specific survival were estimated in Cox proportional-hazard models. (
  • Below this value for EPV, the results of proportional hazards regression analyses should be interpreted with caution because the statistical model may not be valid. (
  • Methods The authors conducted Cox proportional hazards regression analyses of lung cancer risk with cumulative, mean and maximum 'daily weighted average' (DWA) exposure among 5436 workers, using age-based risk sets. (
  • Cox proportional hazards models, univariate and multivariate analyses were used to identify predictors of local failure. (
  • Univariate analyses were conducted using proportional hazards models. (
  • large sample properties did not hold for variance estimates from the proportional hazards model, and the Z statistics used to test the significance of the regression coefficients lost validity under the null hypothesis. (
  • In this secondary analysis, the effect of ECPR on 180-day survival using Kaplan-Meier estimates and Cox proportional hazard model was examined. (
  • Cox models yielded estimates of adjusted hazard ratios, with categorical variables for lagged cumulative exposure to 3 types of MWF (straight, soluble, and synthetic). (
  • For exponential and Weibull models, estimates are available in either the accelerated-time or hazard metric. (
  • This may violate the non-informative censoring assumption of the model and may produce biased effect estimates. (
  • Models utilizing the predicted vital status produce effect estimates consistently stronger and closer to the true treatment effect than estimates produced by models using the initial treatment outcome. (
  • Conclusions: Although studies often use initial treatment outcomes to estimate treatment effects, this may violate the non-informative censoring assumption of the Cox proportional hazards model and result in biased treatment effect estimates. (
  • We introduce a duration model that allows for unobserved cumulative individual-specific shocks, which are likely to be important in explaining variations in duration outcomes, such as length of life and time spent unemployed. (
  • Methods: We derive and apply a logistic regression model to predict vital status at the end of the cohort period and modify the unobserved survival outcomes to better match the predicted survival experience of study subjects. (
  • Cox proportional hazards models were fitted to evaluate the relationship between kidney function and vascular outcomes. (
  • We explored the association between complete and proportional ABCDEF bundle performance and three sets of outcomes: patient-related (mortality, ICU and hospital discharge), symptom-related (mechanical ventilation, coma, delirium, pain, restraint use), and system-related (ICU readmission, discharge destination). (
  • Validity is assessed in a set of simulation experiments and results indicate that the proposed procedure performs well in producing data that conform to the assumptions of the Cox proportional hazards model. (
  • Exposure-response patterns were consistent with prior reports from this cohort, and results for splined exposures generally reflected their categorically modeled counterparts. (
  • Prognostic model for survival in patients with metastatic renal cell carcinoma: results from the international kidney cancer working group. (
  • Multiple datasets are created, models run, and results pooled so conclusions can be drawn. (
  • Kaplan-Meier estimator and Cox proportional hazard model were used to assess the association with predictors. (
  • Suppose there is a series of observations from a univariate distribution and we want to estimate the mean of that distribution (the so-called location model ). (
  • Quasi maximum likelihood estimation and prediction in the compound Poisson ECOGARCH(1,1) model. (
  • Modeling dependencies between rating categories and their effects on prediction in a credit risk portfolio. (
  • Prediction models for circulatory mortality in men and women had optimism adjusted C-statistics and R2 statistics between 0.75-0.77 and 0.33-0.44, respectively. (
  • This model showed acceptable discrimination and good calibration for risk prediction of chronic cardio-metabolic disorders in short and long-term follow-up in the Iranian population. (
  • We apply the IMPH model to study the relationships among socioeconomic status, health shocks, and mortality, using 19 waves of data drawn from the German Socio-Economic Panel (SOEP). (
  • OBJECTIVE To use various exposure-response models to estimate the risk of mortality from lung cancer due to occupational exposure to respirable crystalline silica dust. (
  • METHODS Data from a cohort mortality study of 2342 white male California diatomaceous earth mining and processing workers exposed to crystalline silica dust (mainly cristobalite) were reanalyzed with Poisson regression and Cox's proportional hazards models. (
  • For those who died of lung cancer the linear relative rate model predicted rate ratios for mortality from lung cancer of about 1.6 for the mean cumulative exposure to respirable silica compared with no exposure. (
  • Cox analysis revealed that TB-related mortality hazard ratios included treatment default (8.9), multidrug resistance (5.7), recently transmitted TB (4.1), weight loss (3.9), and hav- ing less than 6 years of formal education (2). (
  • The Cox proportional hazards model has been a common choice in analysing data to understand factors strongly associated with high child mortality rates taking age as the time-to-event variable. (
  • The hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality were estimated using a Cox regression model. (
  • Cox proportional hazard logistic regression models were estimated to determine the association between religious service attendance and mortality. (
  • Participants with the most frequent religious service attendance had a 47% reduction of all-cause mortality risk compared their peer who did not attend religious services at all (HR 0.53, CI 0.35-0.79) in the fully adjusted model including socioeconomic status, non-cardiovascular medical conditions, health behaviors, social support and allostatic load. (
  • Cox proportional hazard models with age at study entry as the time scale were used to investigate the relationship between DIS diagnoses and mortality, adjusted for participant education, smoking and obesity at baseline. (
  • The topics will include non-parametric statistical methods, linear models, logistic regression, Generalized Linear Models and Poisson regression, and survival analysis. (
  • The same is true of the parametric models. (
  • The authors used Cox proportional hazards regression models to estimate relative risks and 95% confidence intervals. (
  • Because the shear wave velocity reduction is proportional to the percentage of serpentines in the mantle, we can use velocity reduction to estimate the degree of serpentinisation, and therefore, the amount of water that has been released from the subducted slab," said Assistant Professor Ping Tong, a Principal Investigator at EOS who co-authored the study. (
  • combining extensive sea and land surface temperature reconstructions from the Last Glacial Maximum with climate model simulations we estimate a lower median (2.3 K) and reduced uncertainty (1.7-2.6 K 66% probability). (
  • The model estimate of the cooling during the Last Glacial Maximum is a clear underestimate. (
  • This paper develops a new semiparametric approach for the estimation of hazard functions in the presence of unobserved heterogeneity. (
  • Partial likelihood estimation of isotonic proportional hazards models. (
  • Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time. (
  • 0.05) in nearly all of the models evaluated and the linear relative rate model with a 10 year exposure lag seemed to give the best fit in the Poisson regression analysis. (
  • Zero-inflated generalized Poisson models with regression effects on the mean, dispersion and zero-inflation level applied to patent outsourcing rates. (
  • A geoadditive Bayesian latent variable model for Poisson indicators. (
  • Multivariable analysis using a log-logistic model stratified by center and multivariable fractional polynomials was conducted to identify independent predictors of survival. (
  • We constructed a semi-Markov cohort model using data from the North American Opiate Medication Initiative trial, supplemented with administrative data for the province of British Columbia and other published data, to capture the chronic, recurrent nature of opioid dependence. (
  • For incident stroke and MI, addition of RV to FRS did not improve model performance in either cohort. (
  • Although the non-malignant respiratory health hazards of occupational exposure to dust have been known for centuries, the possibility of an association of occupational exposure to respirable crystalline silica dust with lung cancer has been debated in the scientific literature in recent decades. (
  • EPID 747 Environmental Epidemiology (3) (Prereq: EPID 700, BIOS 700) (spring of every even year) Emphasis on the epidemiology of selected environmental factors which may affect human health including the identification of health hazards and methods of investigation. (
  • Survival trees and random survival forests are increasingly becoming popular in analysing survival data particularly in the case of large survey data and could be attractive alternatives to models with the restrictive PH assumption. (
  • Additional y, most specimens were col ected shared frailty model, which is an extension of the Cox from cases in Cebu province, including from the independ- proportional hazards model that accounts for clustering, ent cities of Cebu City, Lapu-Lapu City and Mandaue City and the proportional hazards assumption was checked (191 [60.3%] of specimens overall and 48/68 [70.6%] using Schoenfeld residuals. (
  • Modelling count data with overdispersion and spatial effects. (
  • Annual PM2.5 concentrations were estimated using a satellite-based model with national coverage and 1 x 1 km spatial resolution. (
  • Research into a predictive, as opposed to prognostic, model could be highly beneficial and aid the identification of the most suitable treatment for patients. (
  • A nonparametric predictive alternative to the Imprecise Dirichlet Model: the case of a known number of categories. (
  • The hazard function is specified parametrically, whereas the distribution of the unobserved heterogeneity is indirectly estimated using the method of kernels. (
  • This paper applies discrete-time proportional hazards models with unobserved heterogeneity for several worker skill measures and human capital accumulation, interacted with firm-size categories and industry knowledge-intensity to ascertain how knowledge-skill complementarities are influenced by firm size. (
  • We compare and contrast this model with the mixed proportional hazard (MPH) model, which continues to be the workhorse of applied single-spell duration analysis in economics and the other social sciences. (
  • Dependence Measures in Bivariate Gamma Frailty Models * Bivariate duration data frequently arise in economics, biostatistics and other areas. (
  • 42 studies were identified and both the data collection and modelling methods were compared. (
  • One of most popular methods for survival analysis is Cox proportional hazards regression. (
  • 9 ] investigated the survival of patients following paclitaxel and platinum chemotherapy and found histology to be a significant predictor of overall survival in multivariate Cox proportional hazards regression. (
  • We derived a Cox regression model comparing differences in time to TB diagnosis after US entry among 19 birth regions, adjusting for sex, birth year, and age at entry. (
  • Relating in vitro to in vivo exposures with physiologically-based tissue dosimetry and tissue response models. (
  • The present study aimed to construct a model based on pyroptosis-related long-stranded non-coding RNA (lncRNA) to evaluate the potential prognostic application in bladder cancer. (
  • Therefore, we aimed to investigate the role of prognostic factors on breast cancer survival using Additive Empirical Bayesian model with large data set. (
  • Nine clinical factors can be used to model survival in mRCC and form distinct prognostic groups. (
  • 0.001] were prognostic in univariable models. (
  • The best-fitting models were generally categorical or piecewise log-linear, with the steepest increase in lung cancer risk between 0 and 10 μg/m 3 for both mean and maximum DWA exposure and between 0 and 200 μg/m 3 -days for cumulative DWA exposure. (
  • Performance of Framingham risk scores (FRS) for incident stroke and incident MI, with addition of RV to FRS, were compared with a simpler model based on RV, age, smoking status and medical history (antihypertensive/cholesterol lowering medication, diabetes, prevalent stroke/MI). (
  • An essential starting point for simulation studies of time-to-event models is the ability to produce simulated survival times from a known data generating process. (
  • The IMPH model is found to fit the data statistically better than the MPH model, and unobserved health shocks and socioeconomic status are shown to play powerful roles in predicting longevity. (
  • Data were analyzed using Cox proportional hazards regression models. (
  • When using Cox proportional hazards models to analyze these cohorts, this leads to censoring subjects at the time of the initial treatment outcome, instead of them providing full survival data. (
  • The model was validated using an independent data set of 645 patients treated with tyrosine kinase inhibitor (TKI) therapy. (
  • The experimental data indicate that the CDW consists on an alternating Star of David and trihexagonal distortions and its dynamics goes beyond the classical weak-coupling scenario and is discussed within strong-electron phonon coupling and non-adiabatic models. (
  • Such an approach willCited by: Concerning bivariate least squares linear regression, the classical re-sults obtained for extreme structural models in earlier attempts [18] [11] are reviewed using a new formalism in terms of deviation (matrix) traces which, for homoscedastic data, reduce to usual quantities leaving aside an unessential (but dimensional) multiplicative factor. (
  • Moreover, adding data of educational levels and marital status did not improve, the discrimination and calibration in the enhanced model. (
  • Because seismic noise occurs all the time and from a variety of locations, we had a wealth of data to construct a high-resolution 3D shear wave velocity model of Myanmar," said Dr Shucheng Wu, a Research Fellow at EOS and the lead author of the study. (
  • For example, the study uses a relatively new global mean surface temperature reconstruction for the LGM of just 2.2°C cooler than interglacial temperatures in the locations where they have proxy data, or 2.6°C from the global model average. (
  • In this model, two key work characteristics-(1) one's job demands and (2) the level of one's decision latitude-combine to determine the risk of psychological strain and physical illness. (
  • The estimated mean DWA beryllium exposure associated with 10 −3 excess lifetime risk based on the piecewise log-linear model is 0.033 μg/m 3 . (
  • Subdistribution hazards models to evaluate the outcome risk with non-CVD death treated as a competing event. (
  • In a multivariable model, the highest cancer risk was calculated among nonpersistent statin users. (
  • The present study used proportional hazards models with the General Social Survey, Cycles 20 and 21, to assess the impact of providing care to a partner, a parent or parent-in-law, another relative, or a non-relative on the risk of leaving employment. (
  • The median age of all cases models were adjusted for morbidity, week of specimen was 33 years (interquartile range [IQR]: 21-46), and 142 col ection of first positive test, age, sex and province. (
  • In normal distribution models, we are familiar with using the ordinary product moment correlation (Pearson correlation) for measuring the dependence between the various : Philip Hougaard. (
  • In "bivariate frailty models", dependence between the frailties (i.e., unobserved determinants) induces dependence between the durations. (
  • INTERVENTIONS We defined ABCDEF bundle performance (our main exposure) in two ways: 1) complete performance (patient received every eligible bundle element on any given day) and 2) proportional performance (percentage of eligible bundle elements performed on any given day). (
  • This study aimed to assess the hygiene quality of some packaged milk [‎pasteurized or sterilized]‎ and dairy products before and after application of a hazard analysis and critical control point [‎HACCP]‎ system at a milk and dairy products company in Cairo, Egypt. (
  • His Meningioma study combines topics from a wide range of disciplines, such as Transcriptome, Local failure and Proportional hazards model. (
  • For external validation of the model in the Tehran lipids and glucose study (TLGS), the Area under the curve (AUC) and the Hosmer-Lemeshow (HL) goodness of fit test were performed for discrimination and calibration, respectively. (
  • Another concern regarding the study is in the model they used - the University of Victoria (UVic) climate model. (
  • Early detection of musculoskeletal disorders in the workplace if followed by appropriate preventive interventions like hazard reduction, modified work, recovery time, task rotation or other measures can serve as tools for primary prevention. (
  • Evaluations of the fit of the models were performed by comparing their deviances. (
  • Cody, I have tried the survreg() in the Design library, it is analogous to survreg() in the survival library and it seems to me it is designed only for accelerated time models like the accelerated failure model (or accelerated lifetime model) and not for proportional hazard models. (
  • Her main research lines include the analysis of time series, models for load forecasting (long, medium and short term), machine learning and clustering, which are key techniques to develop suitable Demand Response programs. (
  • Importance of events per independent variable in proportional hazards regression analysis. (
  • A Bayesian semiparametric latent variable model for mixed responses. (
  • However, despite the wide use of Karasek's model in the literature (as well as variations such as the demand-control-support model), empirical evidence for this model is mixed (Totterdell, Wood, and Wall, 2006). (
  • Propriety of Posteriors in Structured Additive Regression Models: Theory and Empirical Evidence. (
  • Age, gender, drug dosage, comorbidities of diabetes and heart failure (HF), and characteristics of the first hospitalization due to IS were all adjusted in models. (