Proportional Hazards Models
Risk Factors
Cohort Studies
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.
Follow-Up Studies
Prospective Studies
Prognosis
Survival Analysis
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.
Kaplan-Meier Estimate
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)
Incidence
Retrospective Studies
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.
Survival Rate
Multivariate Analysis
Risk Assessment
Treatment Outcome
Predictive Value of Tests
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.
Risk
Cause of Death
Age Factors
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.
Neoplasm Staging
Confidence Intervals
Disease-Free Survival
Longitudinal Studies
Cardiovascular Diseases
Registries
SEER Program
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)
Questionnaires
Sex Factors
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.
Disease Progression
Neoplasm Recurrence, Local
Confounding Factors (Epidemiology)
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.
Tumor Markers, Biological
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.
Kidney Failure, Chronic
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.
Stroke
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)
Comorbidity
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.
Body Mass Index
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)
European Continental Ancestry Group
Chi-Square Distribution
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.
Odds Ratio
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.
Myocardial Infarction
Renal Dialysis
Coronary Disease
Biological Markers
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.
Severity of Illness Index
Colorectal Neoplasms
Lymphatic Metastasis
Epidemiologic Methods
Postmenopause
HIV Infections
Heart Failure
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.
Neoplasms
African Americans
Regression Analysis
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.
Age Distribution
Coffee
Models, Statistical
Alcohol Drinking
Diabetes Mellitus, Type 2
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.
Combined Modality Therapy
Antiretroviral Therapy, Highly Active
Analysis of Variance
CD4 Lymphocyte Count
Diabetes Mellitus
Chemotherapy, Adjuvant
Databases, Factual
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.
Sex Distribution
Case-Control Studies
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.
Logistic Models
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.
African Continental Ancestry Group
Hypertension
Survival
Prostate-Specific Antigen
Life Style
Hip Fractures
Diabetes Complications
Socioeconomic Factors
Treatment Failure
Age of Onset
Prostatectomy
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).
Randomized Controlled Trials as Topic
Genotype
Carcinoma, Squamous Cell
Ovarian Neoplasms
Receptors, Estrogen
Residence Characteristics
Anti-HIV Agents
Dementia
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.
Biometry
Prevalence
Endometrial Neoplasms
Immunohistochemistry
Multicenter Studies as Topic
Health Surveys
Diet Surveys
Life Tables
Carcinoma, Hepatocellular
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.
Neoplasm Grading
Estrogen Replacement Therapy
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.
Netherlands
Receptors, Progesterone
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.
beta Carotene
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.)
ROC Curve
Coronary Artery Disease
Aging
Glomerular Filtration Rate
Carcinoma, Non-Small-Cell Lung
Data Interpretation, Statistical
Antineoplastic Combined Chemotherapy Protocols
Outcome Assessment (Health Care)
Polymorphism, Single Nucleotide
Reproducibility of Results
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.
Medicare
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, Adjuvant
Death, Sudden, Cardiac
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)
Death
Pancreatic Neoplasms
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).
Brain Neoplasms
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.
Dairy Products
C-Reactive Protein
Survivors
Neoplasm Metastasis
National Institutes of Health (U.S.)
Menopause
Ethnic Groups
Reproductive History
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.
Carcinoma, Renal Cell
Nomograms
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.
Chronic Disease
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)
Obesity
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).
Biostatistics
Double-Blind Method
Pregnancy
Genetic Predisposition to Disease
Population Surveillance
Dietary Supplements
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.
Neoplasms, Second Primary
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.
Bias (Epidemiology)
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.
Peritoneal Dialysis
Peripheral Arterial Disease
Hydroxymethylglutaryl-CoA Reductase Inhibitors
Graft Survival
Postoperative Complications
Occupational Exposure
British Columbia
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)
Asian Continental Ancestry Group
Hawaii
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)
Adenocarcinoma, Mucinous
Carcinoma
Canada
Morbidity
Karnofsky Performance Status
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.
Viral Load
Neoplasms, Glandular and Epithelial
Nurses
Continental Population Groups
Melanoma
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)
Osteoporotic Fractures
Reoperation
Computer Simulation
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)
survival - Interval censored Cox proportional hazards model in R - Cross Validated
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FRI0145 The effect of adalimumab on risk of major adverse cardiovascular events in rheumatoid arthritis: A meta-analysis of...
SVR Improves Mortality 3-Fold - Association Between Sustained Virological Response and All-Cause Mortality Among Patients With...
Correlation of infusion-related reactions (IRR) and outcome in patients receiving NGR-HTNF treatment | OncologyPRO
Potential effect of various immunocompetent cells from | Open-i
存活分析(Survival analysis)介紹Ⅳ-Cox proportional hazard model (Cox regression)~晨晰統計林星帆顧問整理 @ 晨晰統計部落格新站(統計、SPSS、BIG DATA討論園地) :: 痞客邦...
name: T. Obel found 1 record • Arctic Health
Cardiovascular biomarkers in patients with cancer and their association with all-cause mortality | Heart
Cancer Research, Statistics, and Treatment
Clinical Application of Liquid Biopsies for Disease Monitoring and Understanding Therapeutic Resistance in Metastatic Breast...
STAT 311: Applied Survival Analysis: Mathematics and Statistics: Loyola University Chicago
Partially linear single index Cox regression model in nested case-control studies
Isomerases
Early presence of anti-angiogenesis-related adverse events as a potential biomarker of antitumor efficacy in metastatic gastric...
Hazard function synonyms, Hazard function antonyms - FreeThesaurus.com
SCMR 2020
Category: Survival analysis
JoVE Author Search: Caan BJ
R: Fit Proportional Hazards Regression Model
[email protected]: 장기요양 인정자의 최초 재가급여 선택과 유지 및 이탈에 대한 영향요인: Aging in Place 지원을 위한 탐색
[email protected]: 장기요양 인정자의 최초 재가급여 선택과 유지 및 이탈에 대한 영향요인: Aging in Place 지원을 위한 탐색
Applying Cox regression to competing risks
Wernroth, Lisa
AFib Patients Who Exercise Lower Mortality Risk, Live Longer: Study
Pushpa Publishing House
Plus it
Time-dependent mediators in survival analysis: Modeling direct and indirect effects with the additive hazards model -...
Higher muscle mass associated with lower mortality risk in people with heart disease | UCLA
The time to degree or dropout amongst full-time masters students at University of KwaZulu-Natal
Most recent papers with the keyword Health and fitness | Read by QxMD
Most recent papers with the keyword CRF | Read by QxMD
Qing Pan and Doug Schaubel, Lauréats du prix de La revue canadienne de statistique 2009 | Société statistique du Canada
Plus it
Longer Life Foundation : Cancer Patient-Specific Prognostic Information
r - Using strata instead of stratifying groups separately? - Cross Validated
CiteSeerX - Generalized Additive Models
Development and validation of a prediction rule for recurrent vascular events based on a cohort study of patients with arterial...
Applied Survival Analysis by Hosmer, Lemeshow and MayChapter 4: Interpretation of a Fitted Proportional Hazards Regression...
Survival Analysis I - Dalla Lana School of Public HealthDalla Lana School of Public Health
Новый Палгрейв: словарь по экономике - Википедия
proportional hazard model. *prospect theory. *protoindustrialization. *psychological games. *psychology of social networks ... The New Palgrave: Dictionary of Economics, Volume 7 real balances - stochastic volatility models ...
Regression dilution
... 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: 1056-1066. doi:10.2307/2532247. ... The case that x is fixed, but measured with noise, is known as the functional model or functional relationship. See, for ... Carroll, R. J., Ruppert, D., and Stefanski, L. A. (1995). Measurement error in non-linear models. New York, Wiley. Riggs, D. S ...
Survival analysis
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 ...
Mare reproductive loss syndrome
"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 ...
Customer attrition
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 ...
Multicollinearity
"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 ...
MedCalc
Survival analysis includes Cox regression (Proportional hazards model) and Kaplan-Meier survival analysis. Procedures for ...
Cinnabar moth
An Analysis Based on the Proportional Hazards Model."Journal of Animal Ecology , Vol. 54, No. 3 (Oct., 1985). ...
Nested case-control study
"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 ...
Kaplan-Meier estimator
... 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, ... Kaplan-Meier estimator can be derived from maximum likelihood estimation of hazard function. More specifically given d i {\ ... "sts - Generate, graph, list, and test the survivor and cumulative hazard functions" (PDF). Stata Manual. Cleves, Mario (2008). ...
Flow sampling
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 ...
Logrank test
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 ...
Patricia Grambsch
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 ... Reviews of Modeling Survival Data: Broström, Göran, zbMATH, Zbl 0958.62094CS1 maint: untitled periodical (link) Borgan, Ørnulf ...
David Cox (statistician)
The proportional hazards model, which is widely used in the analysis of survival data.[4] An example is survival times in ... Cox proportional hazards model. Stochastic processes. Design of experiments. Analysis of binary data. ... "the development of the Proportional Hazard Regression Model." In 2010 he was awarded the Copley Medal of the Royal Society "for ... Time series models in econometrics, finance and others (Chapman & Hall/CRC, 1996). With D. V. Hinkley and Ole E. Barndorff- ...
David Cox (statistician)
The proportional hazards model, which is widely used in the analysis of survival data, was developed by him in 1972. An example ... "the development of the Proportional Hazard Regression Model." In 2010 he was awarded the Copley Medal of the Royal Society "for ... Time series models in econometrics, finance and others (Chapman & Hall/CRC, 1996). With D. V. Hinkley and Ole E. Barndorff- ... Cox, David R (1972). "Regression Models and Life-Tables". Journal of the Royal Statistical Society, Series B. 34 (2): 187-220. ...
Poisson regression
... 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 ...
Randomized controlled trial
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 ...
Nancy Flournoy
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, ...
Cyntha Struthers
... 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 ...
Lasso (statistics)
... 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 {\ ...
Perfluorooctanoic acid
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 5-year birth cohort. The ... hazard ratio = 1.10 and 1.34, respectively, for a 1-unit increase in log-transformed serum PFOA]. The study consisted of 32,254 ...
Cinnabar moth
An Analysis Based on the Proportional Hazards Model." Journal of Animal Ecology. 54 (3). Coombs, E. M., et al., Eds. (2004). ...
Formica polyctena
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, ...
List of statistics articles
Propensity probability Propensity score Propensity score matching Proper linear model Proportional hazards models Proportional ... model Hierarchical Bayes model Hierarchical clustering Hierarchical hidden Markov model Hierarchical linear modeling High- ... model) - a time series model Sethi model Seven-number summary Sexual dimorphism measures Shannon-Hartley theorem Shape of the ... latent variable model Latent class model Latent Dirichlet allocation Latent growth modeling Latent semantic analysis Latin ...
Likelihood function
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 ... Instead, what is used is the relative likelihood of models (see below). The likelihood ratio of two models, given the same ... one compares models (parameters), holding data fixed; while in odds, one compares events (outcomes, data), holding the model ...
Compensation law of mortality
... 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. ...
Risk score
... 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 ...
Overfitting
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, ...
One in ten rule
... in particular proportional hazards models in survival analysis and logistic regression) while keeping the risk of overfitting ... "Chapter 8: Statistical Models for Prognostication: Problems with Regression Models". Archived from the original on October 31, ... Harrell, F. E. Jr.; Lee, K. L.; Mark, D. B. (1996). "Multivariable prognostic models: issues in developing models, evaluating ... Alternatively, three requirements for prediction model estimation have been suggested: the model should have a global shrinkage ...
Cox
... oxide capacitance in MOSFET devices Cox model, a proportional hazards model in statistics Cox model engines, made by L.M. Cox ... an Atlanta-based business unit of Cox Enterprises Cox Models, aka Cox Hobbies Cox Sports, a regional sports network that served ...
Level of measurement
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ... Rasch, G. (1960). Probabilistic models for some intelligence and attainment tests. Copenhagen: Danish Institute for Educational ... Further progress was made by Georg Rasch (1960), who developed the probabilistic Rasch model that provides a theoretical basis ... For example, applications of measurement models in educational contexts often indicate that total scores have a fairly linear ...
Mann-Whitney U test
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ...
Developing country
It assumes a desire to develop along the traditional Western model of economic development which a few countries, such as Cuba ... They conclude that the percentage of the schooled population is proportional to the economic growth rate and inversely ... Rapid environmental and health hazards.. *Traffic fatalities and air pollution.. *Non communicable diseases. ... It assumes a desire to "develop" along the traditional Western model of economic development, which a few countries, such as ...
Coaxial cable
With sufficient power this could be a hazard to people near the cable. A properly placed and properly sized balun can prevent ... The outer diameter is roughly inversely proportional to the cutoff frequency. A propagating surface-wave mode that does not ... Coaxial cable is a particular kind of transmission line, so the circuit models developed for general transmission lines are ... with the depth of penetration being proportional to the square root of the resistivity. This means that, in a shield of finite ...
Isotonic regression
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ...
Biodiesel
Space-filling model of ethyl stearate, or stearic acid ethyl ester, an ethyl ester produced from soybean or canola oil and ... This was attributed to the faster pressure drop at the edge of the spray pattern; there was a proportional relationship between ... Hazard. Mater. 107: 11-25. doi:10.1016/j.jhazmat.2003.11.013.. ... Space-filling model of methyl linoleate, or linoleic acid ... Rudolf Diesel's prime model, a single 10 ft (3.0 m) iron cylinder with a flywheel at its base, ran on its own power for the ...
Probability distribution
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ... The cache language models and other statistical language models used in natural language processing to assign probabilities to ... Such quantities can be modeled using a mixture distribution. Related to real-valued quantities that grow linearly (e.g. errors ... Well-known discrete probability distributions used in statistical modeling include the Poisson distribution, the Bernoulli ...
Opinion poll
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ... This can be done for instance using test-retest,[19] quasi-simplex,[20] or mutlitrait-multimethod models.[21] ... A user-centric model of voting intention from social media. Proceedings of the 51st Annual Meeting of the Association for ... Another source of error stems from faulty demographic models by pollsters who weigh their samples by particular variables such ...
Wave power
In a sea state, the average(mean) energy density per unit area of gravity waves on the water surface is proportional to the ... and may represent hazards to safe navigation.[33] Waves generate about 2,700 gigawatts of power. Of those 2,700 gigawatts, only ... General circulation model. *Geostrophic current. *Global Ocean Data Analysis Project. *Gulf Stream ... The above formula states that wave power is proportional to the wave energy period and to the square of the wave height. When ...
Chi-squared test
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ... for testing whether there is evidence of the need to move from a simple model to a more complicated one (where the simple model ... In order to model the observations regardless of being normal or skewed, Pearson, in a series of articles published from 1893 ... the Pearson distribution to model the observation and performing the test of goodness of fit to determine how well the model ...
Random assignment
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ... More advanced statistical modeling can be used to adapt the inference to the sampling method. ...
Lighting
More critical or optimized designs now routinely use mathematical modeling on a computer using software such as Radiance which ... Generally speaking, the energy expended is proportional to the design illumination level. For example, a lighting level of 400 ... however they contain mercury which is a disposal hazard. Due to the ability to reduce electricity consumption, many ... a standardized model of human visual brightness perception. In English, "lux" is used in both singular and plural.[27] ...
Student's t-test
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ... Suppose one is fitting the model Y. =. α. +. β. x. +. ε. {\displaystyle Y=\alpha +\beta x+\varepsilon }. where x is known, α ...
Static electricity
This is not considered to be a hazard for dust clouds.. *Propagating brush discharge is high in energy and dangerous. Occurs ... For modelling the effect of static discharge on sensitive electronic devices, a human being is represented as a capacitor of ... and can be roughly proportional to particulate flow.[11] Dust clouds of finely powdered substances can become combustible or ... Carlos Hernando Díaz, Sung-Mo Kang, Charvaka Duvvury, Modeling of electrical overstress in integrated circuits Springer, 1995 ...
Structural equation modeling
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ... Assessment of model and model fit[edit]. Having estimated a model, analysts will want to interpret the model. Estimated paths ... Model specification[edit]. Two main components of models are distinguished in SEM: the structural model showing potential ... Structural equation modeling (SEM) is a form of causal modeling that includes a diverse set of mathematical models, computer ...
Structural break
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ... Structural breaks in cointegration models[edit]. For a cointegration model, the Gregory-Hansen test (1996) can be used for one ... Structural changes and model stability in panel data are of general concern in empirical economics and finance research. Model ... For linear regression models, the Chow test is often used to test for a single break in mean at a known time period K for K ∈ [ ...
Design of experiments
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ... Some discussion of experimental design in the context of system identification (model building for static or dynamic models) is ... In the most basic model, cause (X) leads to effect (Y). But there could be a third variable (Z) that influences (Y), and X ... Charles S. Peirce also contributed the first English-language publication on an optimal design for regression models in 1876.[6 ...
Radiation protection
These ideas are combined to form the linear no-threshold model which says that there is not a threshold at which there is an ... The occupational hazards from airborne radioactive particles in nuclear and radio-chemical applications are greatly reduced by ... and to a first approximation is proportional to the total mass of material per unit area interposed along the line of sight ... This most often creates a secondary radiation hazard, as the absorbing nuclei transmute to the next-heavier isotope, many of ...
Blinded experiment
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ...
Dominican Republic
Hazard, Samuel (1873). Santo Domingo, Past And Present; With A Glance At Haytl. p. 249.. ... The Dominican Republic's first Constitution was adopted on November 6, 1844, and was modeled after the United States ... A proportional representation of the Dominican Republic's exports. The Dominican Republic is the largest economy[24] (according ... Schools are based on a Spanish educational model; English and French are mandatory foreign languages in both private and public ...
Atomic force microscopy
It is also inversely proportional to the length of the cantilever. The relative popularity of the beam-deflection method can be ... Thomas, G.; Y. Ouabbas; P. Grosseau; M. Baron; A. Chamayou; L. Galet (2009). "Modeling the mean interaction forces between ... "Drug Delivery and Nanoparticles: Applications and Hazards". International Journal of Nanomedicine. 3 (2): 133-149. doi:10.2147 ... The 'optical leverage' (output signal of the detector divided by deflection of the cantilever) is inversely proportional to the ...
Electromagnetic radiation
Likewise, the momentum p of a photon is also proportional to its frequency and inversely proportional to its wavelength: p. =. ... Particle model and quantum theory[edit]. See also: Quantization (physics) and Quantum optics ... and can be a health hazard. ... Wave model[edit]. Representation of the electric field vector ... They have a special restricted orientation and proportional magnitudes, E. 0. =. c. 0. B. 0. {\displaystyle E_{0}=c_{0}B_{0}}. ...
International Monetary Fund
Argentina, which had been considered by the IMF to be a model country in its compliance to policy proposals by the Bretton ... The clout of member states is roughly proportional to its contribution to IMF finances. The United States has the greatest ... The incentive problem of moral hazard-when economic agents maximise their own utility to the detriment of others because they ...
Electricity
Tleis, Nasser (2008), Power System Modelling and Fault Analysis, Elsevier, pp. 552-54, ISBN 978-0-7506-8074-5. ... Ohm's law is a basic law of circuit theory, stating that the current passing through a resistance is directly proportional to ... replacing the naked flames of gas lighting greatly reduced fire hazards within homes and factories.[73] Public utilities were ... The induced voltage is proportional to the time rate of change of the current. The constant of proportionality is termed the ...
Statistics
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ... A statistical model can be used or not, but primarily EDA is for seeing what the data can tell us beyond the formal modeling or ... Early statistical models were almost always from the class of linear models, but powerful computers, coupled with suitable ... Machine learning models are statistical and probabilistic models that capture patterns in the data through use of computational ...
Bulletproof vest
Thoracic Model Analysis Using Finite Element Modeling and Vibration Table Testing Dr. Peter Matic, Dr. Alan Leung and Mr. Kirth ... Using gravitational force, the height of the drop mass above the vest was proportional to the impact energy. This test ... where the hazards to people and critical structures cannot be lessened by using wheeled robots or other techniques. ... In the early stages of World War II, the United States also designed body armor for infantrymen, but most models were too heavy ...
Electromagnetic spectrum
Photon energy is directly proportional to the wave frequency, so gamma ray photons have the highest energy (around a billion ... making them a health hazard. UV can also cause many substances to glow with visible light; this is called fluorescence. ... Wavelength is inversely proportional to the wave frequency,[5] so gamma rays have very short wavelengths that are fractions of ...
Decomposition of time series
Proportional hazards models. *Accelerated failure time (AFT) model. *First hitting time. Hazard function. *Nelson-Aalen ... whereas a multiplicative model would be y. t. =. T. t. ×. C. t. ×. S. t. ×. I. t. .. {\displaystyle y_{t}=T_{t}\times C_{t}\ ... Enders, Walter (2004). "Models with Trend". Applied Econometric Time Series (Second ed.). New York: Wiley. pp. 156-238. ISBN 0- ... An additive model would be used when the variations around the trend do not vary with the level of the time series whereas a ...
Health effects of tobacco
A person's increased risk of contracting disease is directly proportional to the length of time that a person continues to ... Shihadeh A, Azar S, Antonios C, Haddad A (September 2004). "Towards a topographical model of narghile water-pipe café smoking: ... but having then suppressed the findings or formatted them to imply lessened or no hazard.[237] ...
The Cox Proportional Hazard Model on Fire | MetaFilter
Proportional hazards model - Wikipedia
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 ...
st: proportional hazard assumption in parametric survival models
... From. Magdalena Kapelko ,[email protected],. To. ... st: proportional hazard assumption in parametric survival models. Date. Tue, 7 Jun 2011 01:49:22 +0200. Hi, I am analyzing the ... How to test if proportional hazard assumption holds in parametric survival models that assume Weibull or exponential ... influence of some variables on the probability of failure in the sample of firms using parametric survival model in STATA. ...
Proportional hazards model - encyclopedia article - Citizendium
Proportional hazards models assume that the relative risk remains constant over time.[2] The Cox proportional hazard model is ... an example of a proportional hazards model. References. *↑ Anonymous (2019), Proportional hazards model (English). Medical ... In statistics and regression analysis, proportional hazards models are "statistical models used in survival analysis that ... Retrieved from "http://en.citizendium.org/wiki?title=Proportional_hazards_model&oldid=100375239" ...
Novel Harmonic Regularization Approach for Variable Selection in Cox's Proportional Hazards Model
... heart modelling, cardiovascular and lung dynamics, neurobiology, computational neuroscience, biomechanics, biomedical ... H. H. Zhang and W. Lu, "Adaptive Lasso for Coxs proportional hazards model," Biometrika, vol. 94, no. 3, pp. 691-703, 2007. ... I. Sohn, J. Kim, S.-H. Jung, and C. Park, "Gradient lasso for Cox proportional hazards model," Bioinformatics, vol. 25, no. 14 ... Novel Harmonic Regularization Approach for Variable Selection in Coxs Proportional Hazards Model. Ge-Jin Chu, Yong Liang, and ...
SAS Training in Sweden -- Survival Analysis Using the Proportional Hazards Model
The course focuses on the Cox proportional hazards model, not the parametric models, and is not designed for predictive ... fit the proportional hazards model *assess the fit of the model *fit Cox proportional hazards models for repeated events and ... introduction to the Cox proportional hazards model *model assessment*models with nonproportional hazards * model building and ... The course focuses on the Cox proportional hazards model, not the parametric models, and is not designed for predictive ...
Proportional Hazards Models | Harvard Catalyst Profiles | Harvard Catalyst
"Proportional Hazards Models" by people in Harvard Catalyst Profiles by year, and whether "Proportional Hazards Models" was a ... "Proportional Hazards Models" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH ( ... Proportional Hazards Models*Proportional Hazards Models. *Proportional Hazard Models. *Hazard Model, Proportional ... Below are the most recent publications written about "Proportional Hazards Models" by people in Profiles. ...
Quantify Relative Risk Using a Cox-Proportional Hazards Model: New in Mathematica 9
Proportional hazards models and age-period-cohort analysis of cancer rates
We develop methods for comparative APC analysis of two independent cause-specific hazard rates assuming that an APC model holds ... analysis is widely used in cancer epidemiology to model trends in cancer rates. ... When a given proportional hazards model appears adequate, we derive simple expressions for the relative hazards using ... Proportional hazards models and age-period-cohort analysis of cancer rates Stat Med. 2010 May 20;29(11):1228-38. doi: 10.1002/ ...
R: Fit Proportional Hazards Regression Model
Fit Proportional Hazards Regression Model. Description. Fits a Cox proportional hazards regression model. Time dependent ... The proportional hazards model is usually expressed in terms of a single survival time value for each person, with possible ... model. flags to control what is returned. If these are true, then the model frame, the model matrix, and/or the response is ... A strata term identifies a stratified Cox model; separate baseline hazard functions are fit for each strata. The cluster. ...
Proportional Hazards Models - Semantic Scholar
Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study ... Proportional Hazards Models. Known as: Hazards Models, Proportional, Hazards Model, Proportional, Model, Proportional Hazards ( ... Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study ... Partial least squares proportional hazard regression for application to DNA microarray survival data ...
Proportional Hazard Model - Statistics.com: Data Science, Analytics & Statistics Courses
Proportional Hazard Model:. Proportional hazard model is a generic term for models (particularly survival models in medicine) ... In a proportional hazard model, the effect of an independent variable on the hazard rate is assumed to be multiplicative. For ... Examples of proportional hazard model are exponential, Weibull, and Gompertz models given respectively by ... Cox proposed an ingenious principle for estimating all proportional hazard models without knowing the function h(t) or even the ...
Computed Tomography Image-Based Deep Survival Regression for Metastatic Colorectal Cancer Using a Non-proportional Hazards...
While proportional hazard models are a key instrument for survival analysis within the last centuries, the assumption of hazard ... and significantly reduces the average prediction error compared to the Cox proportional hazards model. ... Schemper, M.: Cox analysis of survival data with non-proportional hazard functions. J. R. Stat. Soc.: Ser. D (Stat.) 41(4), 455 ... Katzman, J.L., Shaham, U., Cloninger, A., Bates, J., Jiang, T., Kluger, Y.: Deep survival: a deep cox proportional hazards ...
SciELO - Brazil - Phenotypic relationships between type traits and productive life using a piecewise Weibull proportional...
Effect of type traits on functional longevity of Czech Holstein cows estimated from a Cox proportional hazards model. Journal ... Effect of type traits on functional longevity of Czech Holstein cows estimated from a Cox proportional hazards model. Journal ... Effect of type traits on functional longevity of Czech Holstein cows estimated from a Cox proportional hazards model. Journal ... Effect of type traits on functional longevity of Czech Holstein cows estimated from a Cox proportional hazards model. Journal ...
A comparison of the polytomous logistic regression and joint cox proportional hazards models for evaluating multiple disease...
The article will promote the use of the joint Cox model in a prospective cohort study. Examples of SAS and S-plus programming ... the joint Cox proportional hazards model is recommended over the polytomous logistic regression model in prospective cohort ... For this reason, an analysis of a real data set was based on the joint Cox proportional hazards model and showed that body size ... A comparison of the polytomous logistic regression and joint cox proportional hazards models for evaluating multiple disease ...
Assessment of contributing risk factors for premature menopause in Bangladesh: Cox proportional hazard model analysis
Assessment of contributing risk factors for premature menopause in Bangladesh: Cox proportional hazard model analysis. Sabrina ... "Assessment of contributing risk factors for premature menopause in Bangladesh: Cox proportional hazard model analysis". Family ... "Assessment of contributing risk factors for premature menopause in Bangladesh: Cox proportional hazard model analysis." Family ... Cox proportional hazard model analysis. Family Medicine & Primary Care Review. 2020;22(3):193-196. doi:10.5114/fmpcr.2020.98240 ...
COX'S PROPORTIONAL HAZARD MODEL AND CONSTRUCTION OF LIFE TABLE FOR UNDER-FIVE | Science Publications
... of under-five children under study is constructed using the estimate of survival function obtained from Coxâ s regression model ... COXS PROPORTIONAL HAZARD MODEL AND CONSTRUCTION OF LIFE TABLE FOR UNDER-FIVE Salam Shantikumar Singh ... of under-five children under study is constructed using the estimate of survival function obtained from Coxâ s regression model ...
Adjusting for bias introduced by instrumental variable estimation in the Cox proportional hazards model, Biostatistics | 10...
"Adjusting for bias introduced by instrumental variable estimation in the Cox proportional hazards model, Biostatistics" on ... the Cox proportional hazards models has become one of the most widely used statistical models due to the ubiquity in medicine ... the Cox proportional hazards models has become one of the most widely used statistical models due to the ubiquity in medicine ... their suitability for estimating Cox proportional hazard models is unclear. It is well known that, in this case, model ...
RePub, Erasmus University Repository:
Comparing a marginal structural model with a Cox proportional hazard model to estimate...
Comparing a marginal structural model with a Cox proportional hazard model to estimate the effect of time-dependent drug use in ... 2014). Comparing a marginal structural model with a Cox proportional hazard model to estimate the effect of time-dependent drug ... The objective of this study was to compare traditional Cox proportional hazard models (with and without time-dependent ... Cardiovascular disease, Confounding, Marginal structural modeling, Methods, Observational studies, Time-dependent exposure ...
Details and Download Full Text PDF: Heritability, reliability of genetic evaluations and response to selection in proportional...
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Duration models and proportional hazards in political science<...
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Determinants of Inter-Trade Durations and Hazard Rates Using Proportional Hazard Arma Models
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The use of Gaussian quadrature for estimation in frailty proportional hazards models<...
Liu L, Huang X. The use of Gaussian quadrature for estimation in frailty proportional hazards models. Statistics in Medicine. ... Liu, L & Huang, X 2008, The use of Gaussian quadrature for estimation in frailty proportional hazards models, Statistics in ... Liu, L., & Huang, X. (2008). The use of Gaussian quadrature for estimation in frailty proportional hazards models. Statistics ... The use of Gaussian quadrature for estimation in frailty proportional hazards models. In: Statistics in Medicine. 2008 ; Vol. ...
Survival analysis: Parametric proportional hazards models
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WeibullCovariatesRatioCox'sRatiosRegression analysisEstimationDownload Tree augmented Cox proportional hazardsLikelihoodEstimateCovariateParametric modelsSemiparametric proportionalDataPredictor variablesKaplan-MeierNonparametricMortalityExplanatory variablesMethodsFrailty modelsLogarithm of the hazardShape of the hazardMathematicsPiecewiseProbabilityAdditiveConfidence intervalsStatistical modelsStrata1972MultivariateCoefficientsFunctionDiscreteSurvival timesTime dependentParameterDantzigAssumptionsGompertzCohortExponential distributionFunctionsPredictiveLogistic RegressionHypothesisPredict
Weibull25
- How to test if proportional hazard assumption holds in parametric survival models that assume Weibull or exponential distribution? (stata.com)
- The author describes data-generating processes for the Cox proportional hazards model with time-varying covariates when event times follow an exponential, Weibull, or Gompertz distribution. (ices.on.ca)
- The objective of this study was to evaluate the relationship of 20 type traits on length of productive life in Brazilian Holsteins, using a piecewise Weibull proportional hazard model. (scielo.br)
- and 2) to examine the relationship between genetic parameters from a Weibull model, a discrete proportional hazard model, and a binary data analysis using a linear model. (pubfacts.com)
- Data were simulated using the Weibull frailty model with two different shapes of the Weibull distribution. (pubfacts.com)
- Three different statistical models were investigated in this study: a Weibull model, a discrete-time model (a proportional hazard model assuming that the survival data are measured on a discrete scale with few classes), and a linear model based upon binary data. (pubfacts.com)
- An alternative derivation using basic expressions of reliabilities in sire models suggests a simple equation for the heritability on the original scale (effective heritability) that is not dependent on the Weibull parameters. (pubfacts.com)
- In general, the estimates of reliability from either the discrete model or the binary data analysis were close to estimates from the Weibull model for a given number of uncensored records in this simplified case of a balanced design. (pubfacts.com)
- Although selection response from the binary data analysis depends on the end of interval point, there is a relatively good agreement between selection responses in the Weibull model and the binary data analysis. (pubfacts.com)
- Comparison between a Weibull proportional hazards model and a linear model for predicting the genetic merit of US Jersey sires for daughter longevity. (pubfacts.com)
- Predicted transmitting abilities (PTA) of US Jersey sires for daughter longevity were calculated using a Weibull proportional hazards sire model and compared with predictions from a conventional linear animal model. (pubfacts.com)
- The effect of ignoring individual heterogeneity in Weibull log-normal sire frailty models. (pubfacts.com)
- The objective of this study was, by means of simulation, to quantify the effect of ignoring individual heterogeneity in Weibull sire frailty models on parameter estimates and to address the consequences for genetic inferences. (pubfacts.com)
- Data were simulated according to balanced half-sib designs using Weibull log-normal animal frailty models with a normally distributed residual effect on the log-frailty scale. (pubfacts.com)
- 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. (stackexchange.com)
- In another design - the Weibull proportional hazards design - the failure times are presumed to follow a theoretical circulation understood as the Weibull circulation. (statshelponline.com)
- Adejumo, A. O. and Ahmadu, A. O. (2016) A Study of the Slope of Cox Proportional Hazard and Weibull Models. (bsijournal.org)
- Gradient Curve of Cox Proportional Harzard and Weibull Models. (bsijournal.org)
- Gompertz PH and Weibull AFT models were used for survival analysis (SA) of these patients. (ac.ir)
- Also, in the Weibull model, birth place and age at onset of the disease were significant factors (p= 0.013, and p= 0.008) in survival time. (ac.ir)
- The Akaike Information Criterion (AIC) for Weibull model was 158.51, which was lower than other parametric models. (ac.ir)
- According to the results, the Weibull AFT model was found to be a better model for identifying the risk factors related to survival of patients with TM disease. (ac.ir)
- In a pdf model based recursive partitioning with adjustment for measurement error applied to the coxs proportional hazards and weibull model of 3,626 boys with biological relationships, miles continued used just of matroid magnets to get terms. (tsp-sound.de)
- To compare the semi-parametric Cox model and parametric [including exponential, Weibull, Gompertz, log-normal, log-logistic and gamma] models and find the best model fitted to studied data, Akaike's Information Criterion [AIC] and Cox-Snell residual were used. (bvsalud.org)
- the best known being the Cox semiparametric proportional hazards model , [1] [3] and the exponential, Gompertz and Weibull parametric models. (wikipedia.org)
Covariates17
- Survival models relate the time that passes, before some event occurs, to one or more covariates that may be associated with that quantity of time. (wikipedia.org)
- and the effect parameters, describing how the hazard varies in response to explanatory covariates. (wikipedia.org)
- The proportional hazards condition states that covariates are multiplicatively related to the hazard. (wikipedia.org)
- The effect of covariates estimated by any proportional hazards model can thus be reported as hazard ratios. (wikipedia.org)
- This is a partial likelihood: the effect of the covariates can be estimated without the need to model the change of the hazard over time. (wikipedia.org)
- This paper also provides a variance inflation factor together with simulations for adjustment of sample size when additional covariates are included in the model. (nih.gov)
- where L is the hazard function or hazard rate, {x i } are covariates, {b i } are coefficients of the model - effects of the corresponding covariates, and h(t) gives the effect of duration on the hazard rate. (statistics.com)
- The objective of this study was to compare traditional Cox proportional hazard models (with and without time-dependent covariates) with MSM to study causal effects of time-dependent drug use. (eur.nl)
- No multicollinearity among covariates his work [ 1 ] in 1972 any fitting to ensure cox proportional hazards model assumptions underlying is! (oftavisionhealth.com.br)
- Simulated survival time \(T\) influenced by time independent covariates \(X_{j}\) with effect parameters \(\beta_{j}\) under assumption of proportional hazards, stratified by sex. (dwoll.de)
- The algorithms are extended to models with time-dependent covariates. (elsevier.com)
- The proportional hazards design was presented in 1972 by D. R. Cox in order to approximate the results of various covariates affecting the times to the failures of a system. (statshelponline.com)
- 9 covariates were selected to fit colorectal cancer data using Cox Regression Models. (bsijournal.org)
- Cox proportional hazards models are used to model survival time using covariates. (xlstat.com)
- The principle of the Cox proportional hazards model is to link the survival time of an individual to covariates. (xlstat.com)
- Key topics covered include: variable selection, identification of the scale of continuous covariates, the role of interactions in the model, assessment of fit and model assumptions, regression diagnostics, recurrent event models, frailty models, additive models, competing risk models, and missing data. (wiley.com)
- 1995) give more detail on regression dilution in nonlinear models, presenting the regression dilution ratio methods as the simplest case of regression calibration methods, in which additional covariates may also be incorporated. (wikipedia.org)
Ratio21
- Patient centered hazard ratio estimation using principal stratification weights: application to the norccap randomized trial of colorectal cancer screening. (deepdyve.com)
- Bias in estimating the causal hazard ratio when using two-stage instrumental variable methods. (deepdyve.com)
- The differences for hazards ratio are expressed as 0-1 for dichotomic variables, as 1 unit for physical activity, and as standard deviations for continuous variables. (biomedcentral.com)
- For each hazard ratio the 95% confidence interval for the population hazard ratio is presented, providing an interval estimate for the population parameter. (oftavisionhealth.com.br)
- The hazard ratio for mortality in relation to duration at 2.4 years was 0.85, 95% CI=0.83-0.87. (nature.com)
- 80% was associated with poorer survival, hazard ratio 1.10, 95% CI=1.001-1.21. (nature.com)
- The quantities \(exp(b_i)\) are called hazard ratios (HR). A value of \(b_i\) greater than zero, or equivalently a hazard ratio greater than one, indicates that as the value of the \(i^{th}\) covariate increases, the event hazard increases and thus the length of survival decreases. (sthda.com)
- Put another way, a hazard ratio above 1 indicates a covariate that is positively associated with the event probability, and thus negatively associated with the length of survival. (sthda.com)
- In the majority of scenarios, we have an interest in comparing groups with regard to their hazards, and we utilize a danger ratio, which is comparable to a chances ratio in the setting of several logistic regression analysis . (statshelponline.com)
- This hazard ratio (HR) for the outcome-often interpreted as a type of relative risk-is the effect of interest and may be used in epidemiological studies for risk assessment. (hindawi.com)
- It means that the hazard ratio between two different observations does not depend on time. (xlstat.com)
- In survival analysis , the hazard ratio ( HR ) is the ratio of the hazard rates corresponding to the conditions described by two levels of an explanatory variable. (wikipedia.org)
- The hazard ratio would be 2, indicating higher hazard of death from the treatment. (wikipedia.org)
- Or in another study, men receiving the same treatment may suffer a certain complication ten times more frequently per unit time than women, giving a hazard ratio of 10. (wikipedia.org)
- This hazard ratio, that is, the ratio between the predicted hazard for a member of one group and that for a member of the other group, is given by holding everything else constant, i.e. assuming proportionality of the hazard functions. (wikipedia.org)
- In its simplest form, the hazard ratio can be interpreted as the chance of an event occurring in the treatment arm divided by the chance of the event occurring in the control arm, or vice versa, of a study. (wikipedia.org)
- The hazard ratio is simply the relationship between the instantaneous hazards in the two groups and represents, in a single number, the magnitude of distance between the Kaplan-Meier plots. (wikipedia.org)
- [1] When a study reports one hazard ratio per time period, it is assumed that difference between groups was proportional. (wikipedia.org)
- If the proportional hazard assumption holds, a hazard ratio of one means equivalence in the hazard rate of the two groups, whereas a hazard ratio other than one indicates difference in hazard rates between groups. (wikipedia.org)
- Hughes (1993) shows that the regression dilution ratio methods apply approximately in survival models. (wikipedia.org)
- Rosner (1992) shows that the ratio methods apply approximately to logistic regression models. (wikipedia.org)
Cox's7
- This web page accompanies the paper The Dantzig selector in Cox's proportional hazards model by Anestis Antoniadis , Piotr Fryzlewicz and Frederique Letue . (lse.ac.uk)
- At the bottom of this page, you can download R code implementing the main algorithm of the paper: the Dantzig selector for Cox's proportional hazards model. (lse.ac.uk)
- Using instrumental variables to estimate a Cox's proportional hazards regression subject to additive confounding. (deepdyve.com)
- We investigate the proportionality assumption for Cox's semiparametric model in the context of the "liberal peace" debate, using data on international conflict in the postwar period. (elsevier.com)
- In the most popular of these models - Cox's proportional hazards design - no hidden circulation of failure times is presumed. (statshelponline.com)
- Fujimori, K & Nishiyama, Y 2017, ' The l q consistency of the Dantzig selector for Cox's proportional hazards model ', Journal of Statistical Planning and Inference , vol. 181, pp. 62-70. (elsevier.com)
- Cox's proportional hazards (CPH) model is a nonparametric method, which means that it makes no assumptions about the distribution of the response measure. (informit.com)
Ratios11
- The hazards of hazard ratios. (deepdyve.com)
- A key assumption of nearly all widely used duration models is that the hazard ratios (i.e., the conditional relative risks across substrata) are proportional to one another and that this proportionality is maintained over time. (elsevier.com)
- Hazards ratios (HRs) and 95% confidence intervals (CIs) were calculated among the larger cohort (n=27,035). (pubmedcentralcanada.ca)
- 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). (cdc.gov)
- Hazard ratios differ from relative risks and odds ratios in that RRs and ORs are cumulative over an entire study, using a defined endpoint, while HRs represent instantaneous risk over the study time period, or some subset thereof. (wikipedia.org)
- Hazard ratios suffer somewhat less from selection bias with respect to the endpoints chosen and can indicate risks that happen before the endpoint. (wikipedia.org)
- Regression models are used to obtain hazard ratios and their confidence intervals . (wikipedia.org)
- Hazard ratios do not reflect a time unit of the study. (wikipedia.org)
- Hazard ratios become meaningless when this assumption of proportionality is not met. (wikipedia.org)
- Excess risk in the four months after acute infection and hazard ratios with Bonferroni corrected 95% confidence intervals were calculated. (bmj.com)
- 0.001), and hazard ratios ranged from 1.24 to 25.65 compared with the 2020 comparator group. (bmj.com)
Regression analysis3
- In statistics and regression analysis , proportional hazards models are "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. (citizendium.org)
- An alternative method is the Cox proportional hazards regression analysis, which works for both quantitative predictor variables and for categorical variables. (sthda.com)
- They explain the survival inning accordance with one aspect under examination, however overlook the effect of other.An option approach is the Cox proportional hazards regression analysis , which works for both quantitative predictor variables and for categorical variables. (statshelponline.com)
Estimation21
- A counting process approach to maximum likelihood estimation in frailty models. (deepdyve.com)
- Estimation of multivariate frailty models using penalized partial likelihood. (deepdyve.com)
- Two-stage residual inclusion estimation: addressing endogeneity in health econometric modeling. (deepdyve.com)
- Estimation of proportional hazards models when hazards are non-proportional results in coefficient biases and decreased power of significance tests. (elsevier.com)
- In paper, we propose a novel Gaussian quadrature estimation method in various frailty proportional hazards models. (northwestern.edu)
- Liu, L & Huang, X 2008, ' The use of Gaussian quadrature for estimation in frailty proportional hazards models ', Statistics in Medicine , vol. 27, no. 14, pp. 2665-2683. (northwestern.edu)
- In my presentation I will describe the stochastic gradient descent algorithm that was applied in the log- likelihood estimation process of coefficients' calcualtions of the Cox proportional hazards model. (sthda.com)
- Adaptive Penalized Weighted Least Absolute Deviations Estimation for the Accelerated Failure Time Model. (wroc.pl)
- We consider the estimation of the semiparametric proportional hazards model with an unspecified baseline hazard function where the effect of a continuous covariate is assumed to be monotone. (elsevier.com)
- Previous work on nonparametric maximum likelihood estimation for isotonic proportional hazard regression with right-censored data is computationally intensive, lacks theoretical justification, and may be prohibitive in large samples. (elsevier.com)
- Fine, Jason P. / Partial likelihood estimation of isotonic proportional hazards models . (elsevier.com)
- In particular, MMPH models allow for the estimation of several durations per individual. (uni-tuebingen.de)
- Marafa Haliru Muhammad, Usman Umar, Estimation of Population Based Colorectal Cancer Survival Analysis Using Cox Proportional Hazards Model, Biomedical Statistics and Informatics . (bsijournal.org)
- Non-parametric estimation of the survival and cumulative hazard functions. (york.ac.uk)
- It includes imputation methods for dealing with missing data effectively, methods for dealing with nonlinear relationships and for making the estimation of transformations a formal part of the modeling process, methods for dealing with "too many variables to analyze and not enough observations," and powerful model validation techniques based on the bootstrap. (springer.com)
- It starts with the tests of hypotheses and moves on to regression modeling, time-to-event analysis, density estimation, and resampling methods. (routledge.com)
- The author also describes time-to-event nonparametric estimation methods, such as the Kaplan-Meier survival curve and Cox proportional hazards model, and presents histogram and kernel density estimation methods. (routledge.com)
- The objective of this study is to investigate the problem of goodness of fit testing based on nonparametric function estimation techniques for the random censorship model. (koreascience.or.kr)
- Math Nauk 1987 no.3 Estimation of Probability Density and the Hazard Rate Function in the Koziol-Green Model of Random Censorship Abdushukurov, A.A. (koreascience.or.kr)
- Statistics v.19 Maximum Likelihood Estimation of a survival Function under the Koziol-Green Proportional hazards model of random censorship Cheng, P.E.;Lin, G.D. (koreascience.or.kr)
- Statistics v.19 Estimation in the proportional hazards model of random censorship Csorgo, S. (koreascience.or.kr)
Download Tree augmented Cox proportional hazards8
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Likelihood13
- We present a bootstrap resampling plan for the Cox partial likelihood estimator for proportional hazards models with nonrandom explanatory variables. (springer.com)
- The Cox partial likelihood, shown below, is obtained by using Breslow's estimate of the baseline hazard function, plugging it into the full likelihood and then observing that the result is a product of two factors. (wikipedia.org)
- This function can be maximized over β to produce maximum partial likelihood estimates of the model parameters. (wikipedia.org)
- The exact method computes the exact partial likelihood, which is equivalent to a conditional logistic model. (psu.edu)
- Simulation studies show that our method compares favorably with the well-received penalized partial likelihood method and the Monte Carlo EM (MCEM) method, for both normal and Gamma frailty models. (northwestern.edu)
- Maximum likelihood estimates of the regression parameters, the variance components and the baseline hazard function are obtained via the EM algorithm. (sciencenest.com)
- The iterative convex minorant algorithm which uses pool-adjacent-violators techniques has also been shown to perform well in related parametric likelihood set-ups, but evidences computational difficulties under the proportional hazards model. (elsevier.com)
- A class of variable selection procedures for parametric models via nonconcave penalized likelihood was proposed in Fan and Li (2001a). (elsevier.com)
- In this paper, the nonconcave penalized likelihood approach is extended further to the Cox proportional hazards model and the Cox proportional hazards frailty model, two commonly used semi-parametric models in survival analysis. (elsevier.com)
- G. Kauermann and U. Berger, "A smooth test in proportional hazard survival models using local partial likelihood fitting", LIFETIME DATA ANALYSIS , vol. 9, 2003, pp. 373-393. (uni-bielefeld.de)
- In linear and logistic regression models, the ridge regression estimator has been applied as an alternative to the maximum likelihood estimator in the presence of collinearity. (cdc.gov)
- We also characterize the conditions for improper survival functions and the conditions for existence of the maximum likelihood estimates under the proposed ELTH models. (elsevier.com)
- To estimate the β parameters of the model (the coefficients of the linear function), we try to maximize the partial likelihood function. (xlstat.com)
Estimate14
- Sir David Cox observed that if the proportional hazards assumption holds (or, is assumed to hold) then it is possible to estimate the effect parameter(s) without any consideration of the hazard function. (wikipedia.org)
- The use of restricted mean survival time to estimate the treatment effect in randomized clinical trials when the proportional hazards assumption is in doubt. (semanticscholar.org)
- Further, a life table of under-five children under study is constructed using the estimate of survival function obtained from Coxâ s regression model. (thescipub.com)
- We address the potential problems with incorrectly assuming proportionality, illustrate a number of tests for non-proportionality, and conclude with a discussion of how to accurately and efficiently estimate these models in the presence of nonproportional hazards. (elsevier.com)
- Time-to-event data can be used to compute descriptive statistics, estimate parametric and nonparametric distributions, fit a variety of survival models, and perform hypothesis tests. (wolfram.com)
- In labor and population economics, the Mixed Proportional Hazard (MPH) model and its multivariate extensions, the so-called Multivariate Mixed Proportional Hazard (MMPH) models, are state of the art and the most widely used models to estimate durations and their determinants. (uni-tuebingen.de)
- The aim of this study is to estimate the population based colorectal cancer survival analysis using cox Proportional Hazards model, in order to fits colorectal cancer data in population-based research. (bsijournal.org)
- The proportional hazard model could steadily estimate the ETA for longevity of the sires in Japan. (elsevier.com)
- Some of the underlying theory is discussed, including Cox regression to estimate parameters of the model. (xula.edu)
- A Cox model provides an estimate of the treatment effect on survival after adjustment for other explanatory variables. (xlstat.com)
- It allows us to estimate the hazard (or risk) of death, or other event of interest, for individuals, given their prognostic variables. (xlstat.com)
- If we only estimate the second term, a very important hypothesis has to be verified: the proportional hazards hypothesis. (xlstat.com)
- is the estimate of treatment effect derived from the regression model. (wikipedia.org)
- In general, methods for the structural model require some estimate of the variability of the x variable. (wikipedia.org)
Covariate10
- In a proportional hazards model, the unique effect of a unit increase in a covariate is multiplicative with respect to the hazard rate. (wikipedia.org)
- This expression gives the hazard function at time t for subject i with covariate vector (explanatory variables) Xi. (wikipedia.org)
- This paper derives a formula to calculate the number of deaths required for a proportional hazards regression model with a nonbinary covariate. (nih.gov)
- Simulations show that the censored observations do not contribute to the power of the test in the proportional hazards model, a fact that is well known for a binary covariate. (nih.gov)
- Background: The appropriate handling of missing covariate data in prognostic modelling studies is yet to be conclusively determined. (ebscohost.com)
- Effects of covariate omission and categorization when analysing randomized trials with the Cox model. (deepdyve.com)
- Proportional hazard models for survival data, even though popular and numerically handy, suffer from the restrictive assumption that covariate effects are constant over survival time. (uni-bielefeld.de)
- This paper contributes to this area by employing local estimates allowing to fit hazard models in which covariate effects are smoothly varying with time. (uni-bielefeld.de)
- Assessing time-by-covariate interactions in proportional hazards regression models using cubic spline functions. (uni-bielefeld.de)
- Exploring the nature of covariate effects in the proportional hazards model. (uni-bielefeld.de)
Parametric models3
- The course focuses on the Cox proportional hazards model, not the parametric models, and is not designed for predictive modelers. (sas.com)
- 2017) Comparison of Cox Regression and Parametric Models. (bsijournal.org)
- This study aimed to compare the results of the use of the semi-parametric Cox model with parametric models to determine the factors influencing the length of stay of patients in the inpatient units of Women Hospital in Tehran, Iran . (bvsalud.org)
Semiparametric proportional1
- We use a semiparametric proportional hazard model which is augmented by an ARMA structure very similar to the wide spread ACD model to obtain consistent estimates of the baseline survivor function and to capture well known serial dependencies in the trade intensity process. (uni-konstanz.de)
Data48
- In: Jewell N.P., Kimber A.C., Lee ML.T., Whitmore G.A. (eds) Lifetime Data: Models in Reliability and Survival Analysis. (springer.com)
- This approach to survival data is called application of the Cox proportional hazards model, sometimes abbreviated to Cox model or to proportional hazards model. (wikipedia.org)
- To actually run the model, you will need to enter the data into a hazard model regression calculator, which can be found online . (metafilter.com)
- a missing-data filter function, applied to the model.frame, after any subset argument has been used. (psu.edu)
- A key element in any statistical simulation is the existence of an appropriate data-generating process: one must be able to simulate data from a specified statistical model. (ices.on.ca)
- This course will teach you the various methods used for modeling and evaluating survival data or time-to event data. (statistics.com)
- While proportional hazard models are a key instrument for survival analysis within the last centuries, the assumption of hazard proportionality might be overly restrictive and their applicability to complex data remains difficult. (springer.com)
- The model is evaluated on multiple datasets, including metastatic colorectal cancer computed tomography imaging data, and significantly reduces the average prediction error compared to the Cox proportional hazards model. (springer.com)
- A resampling study was performed to investigate the effects of different missing data methods on the performance of a prognostic model. (ebscohost.com)
- Frailty models for survival data. (deepdyve.com)
- When studying the causal effect of drug use in observational data, marginal structural modeling (MSM) can be used to adjust for time-dependent confounders that are affected by previous treatment. (eur.nl)
- What I have done so far: used 9 months of data to fit the model and 3 remaining months as a holdout validation set. (stackexchange.com)
- From an inspection of conditional transaction probabilities based on Bund future transaction data of the DTB we find a decreasing hazard shape providing evidence for the use of non-trading intervals as an indication for the absence of price information among market participants. (uni-konstanz.de)
- If we take the functional form of the survival function defined above and apply the following transformation, we arrive at: Cox Model has the proportional hazard and the log-linearity assumptions that a data must satisfy. (oftavisionhealth.com.br)
- Proportional Hazards Models What if the data fails to satisfy the assumptions? (oftavisionhealth.com.br)
- It is the most commonly used regression model for survival data. (oftavisionhealth.com.br)
- Most commonly used regression model for survival data 1 ] in 1972 it 's important test. (oftavisionhealth.com.br)
- Doing it the log-linearity assumptions that a data must satisfy forward to do so in R. there cox proportional hazards model assumptions no for! (oftavisionhealth.com.br)
- Has the proportional hazard and the log-linearity assumptions that a data must satisfy assumption is n't violated Cox hazards! (oftavisionhealth.com.br)
- We first apply our method to simple frailty models for correlated survival data (e.g. recurrent or clustered failure times), then to joint frailty models for correlated failure times with informative dropout or a dependent terminal event such as death. (northwestern.edu)
- We apply our method to three real data examples: (1) the time to blindness of both eyes in a diabetic retinopathy study, (2) the joint analysis of recurrent opportunistic diseases in the presence of death for HIV-infected patients, and (3) the joint modeling of local, distant tumor recurrences and patients survival in a soft tissue sarcoma study. (northwestern.edu)
- We propose a general proportional hazards model with random effects for handling clustered survival data. (sciencenest.com)
- The cox proportional-hazards model is one of the most important methods used for modelling survival analysis data. (sthda.com)
- T o illustrate the model, unde r - fi v e child surv iv al data e xtracted from Bangladesh Demogr a phic and Health Sur ve y 2014 h a v e been used. (ac.bd)
- The Cox PH model, because it is built on top of a nonparametric baseline hazard rate, cannot extrapolate to loan ages that are not observed in the data set. (mathworks.com)
- The logistic model treats the age of the loan as a continuous variable, and, therefore, it can extrapolate to predict PDs for ages not observed in the data set. (mathworks.com)
- If, for a particular age, the PD is small and there are no observed defaults in the data, the Cox PH model predicts the PD as zero. (mathworks.com)
- May, M. Royston, P. Egger, M. Justice, A. C. and Sterne, J.A.C. (2004) Development and Validation of Prognosis Model for Survival Time Data: Application to Prognosis of HIV Positive Patients Treated with Anti-retroviral Therapy. (sciencepublishinggroup.com)
- The Cox proportional hazards (PH) model is frequently used to model survival data or time-to-event data, particularly in the presence of censored survival times [ 1 ]. (hindawi.com)
- Also the results show that the data met Cox Proportional Hazards Assumptions. (bsijournal.org)
- Applied Survival Analysis: Regression Modeling of Time- to- Event Data. (bsijournal.org)
- Joeng, HK, Chen, MH & Kang, S 2016, ' Proportional exponentiated link transformed hazards (ELTH) models for discrete time survival data with application ', Lifetime Data Analysis , vol. 22, no. 1, pp. 38-62. (elsevier.com)
- 2. Introduction H2O is an open source, in-memory, distributed, fast, and scalable machine learning and predictive analytics platform Build machine learning models on big data and provides easy productionalization of those models in an enterprise environment. (slideshare.net)
- Objects in the H2O cluster such as data frames, models and results are all referenced by key. (slideshare.net)
- Instead of presenting isolated techniques, this text emphasizes problem solving strategies that address the many issues arising when developing multivariable models using real data and not standard textbook examples. (springer.com)
- Working through the case studies in the book will demonstrate what can be achieved with a little imagination, when modelling complex and challenging data sets. (springer.com)
- Hello, I am a statistician with 2+ years of experience in statistical modeling, data mining, survival analysis, and data visualization on data to derive predictive business insight. (freelancer.com)
- Hi, I have strong statistical background and I have an experince in statistical modelling , analysis and handling data. (freelancer.com)
- The concept of censored data is discussed, and the proportional hazards model is introduced. (xula.edu)
- The proportional hazards model has been developed by Cox (1972) in order to treat continuous time survival data. (xlstat.com)
- Applied Survival Analysis, Second Edition provides a comprehensive and up-to-date introduction to regression modeling for time-to-event data in medical, epidemiological, biostatistical, and other health-related research. (worldcat.org)
- This book fills this gap, providing a comprehensive, self-contained introduction to regression modeling used in the analysis of time-to-event data in epidemiological, biostatistical, and other health-related research. (worldcat.org)
- Most prediction models are developed using a regression model, such as linear regression for continuous outcomes (eg, pain score), logistic regression for binary outcomes (eg, presence or absence of pre-eclampsia), or proportional hazards regression models for time-to-event data (eg, recurrence of venous thromboembolism). (bmj.com)
- Statisticians call this problem censoring , a problem that surfaces when you try to model a time-to-event response measure using data captured over a limited time period. (informit.com)
- Thus, it is often informative to examine the hazard function when time to response data is being analyzed. (pjsor.com)
- In this study Cox proportional hazard model is fitted to patient data of Acute Myeloid Leukemia. (pjsor.com)
- Journal of the American Statistical Association v.74 Nonparametric Statistics Data Modeling Parazen, E. (koreascience.or.kr)
- The course also introduces and explains the concept of modelling survival data based on the widely-use Cox regression model. (jiscmail.ac.uk)
Predictor variables6
- The method does not require assumptions about the distributions of survival time and predictor variables other than proportional hazards. (nih.gov)
- The Cox proportional-hazards model (Cox, 1972) is essentially a regression model commonly used statistical in medical research for investigating the association between the survival time of patients and one or more predictor variables. (oftavisionhealth.com.br)
- The Cox proportional hazard model is basically a regression model generally used by medical researchers to find out the relationship between the survival time of a subject and one or more predictor variables. (kdnuggets.com)
- From the results, it was concluded that the predictor variables could significantly predict the survival of colorectal cancer patients using Cox proportional model. (bsijournal.org)
- CPH models the underlying hazard rate (for example, risk of death) as a function of a baseline hazard rate and the incremental effects of predictor variables. (informit.com)
- 1978). The case of multiple predictor variables subject to variability (possibly correlated) has been well-studied for linear regression, and for some non-linear regression models. (wikipedia.org)
Kaplan-Meier1
- Groups were compared by Cox proportional hazard models and Kaplan-Meier survival plots. (ahajournals.org)
Nonparametric3
- The Cox PH model has a nonparametric baseline hazard rate that can match patterns in the PDs much more closely than the fully parametric logistic model. (mathworks.com)
- The book covers, very completely, the nuances of regression modeling with particular emphasis on binary and ordinal logistic regression and parametric and nonparametric survival analysis. (springer.com)
- It then discusses smoothing techniques (loess and thin-plate splines) for classical nonparametric regression as well as binary logistic and Poisson models. (routledge.com)
Mortality3
- By using statistical modelling, we can assess the extent to which the increased risk of COVID-19 mortality in some religious groups is explained by differences in these factors at the population level. (ons.gov.uk)
- We model the risk of death involving COVID-19 for the whole outcome period, and separately for the first and second waves of the pandemic to explore whether differences in the risk of COVID-19 mortality between different religious groups have changed over time. (ons.gov.uk)
- The hazard, or instantaneous risk, of an event of interest, typically mortality or morbidity, is modeled in terms of one or more explanatory variables relative to an unspecified baseline hazard rate. (hindawi.com)
Explanatory variables5
- Proportional Hazards Model Assumption Let \(z = \{x, \, y, \, \ldots\}\) be a vector of one or more explanatory variables believed to affect lifetime. (oftavisionhealth.com.br)
- In an alternative group of models, the explanatory variables act multiplicatively straight on the failure time. (statshelponline.com)
- In occupational settings, it is common to have an occupational exposure as one of the explanatory variables in the model and the association between the outcome and this exposure is of interest. (hindawi.com)
- A Cox model is a well-recognized statistical technique for exploring the relationship between the survival of a patient and several explanatory variables. (xlstat.com)
- The natural log of the hazard function is the response and two of the explanatory variables age and cellularity level of the patient. (pjsor.com)
Methods10
- We develop methods for comparative APC analysis of two independent cause-specific hazard rates assuming that an APC model holds for each one. (nih.gov)
- In the previous chapter (survival analysis basics), we described the basic concepts of survival analyses and methods for analyzing and summarizing … The proportional hazards assumption is probably one of the best known modelling assumptions with regression and is unique to the cox model. (oftavisionhealth.com.br)
- Furthermore, the Cox regression model extends survival analysis methods to assess simultaneously the effect of several risk factors on survival time. (sthda.com)
- One of the most popular regression methods for survival analysis is Cox proportional hazards regression, which is utilized to relate a number of threat elements or direct exposures, thought about concurrently, to survival time. (statshelponline.com)
- Statistical Methods in Credit Risk Modelling, University of Michigan, 3 4-27. (sciencepublishinggroup.com)
- Truncated power basis expansions and penalized spline methods are demonstrated for estimating nonlinear exposure-response relationships in the Cox proportional hazards model. (hindawi.com)
- Methods for modeling nonlinearities are needed in those situations when a linear exposure-response is not expected or when one desires to formally assess a nonlinear association. (hindawi.com)
- Many different types of models and methods are discussed. (springer.com)
- Since publication of the first edition nearly a decade ago, analyses using time-to-event methods have increased considerably in all areas of scientific inquiry, mainly as a result of model-building methods available in modern statistical software packages. (worldcat.org)
- The reply to Frost & Thompson by Longford (2001) refers the reader to other methods, expanding the regression model to acknowledge the variability in the x variable, so that no bias arises. (wikipedia.org)
Frailty models3
- Supplied penalty functions include ridge regression ( ridge ), smoothing splines ( pspline ), and frailty models ( frailty ). (psu.edu)
- Frailty Models in Survival Analysis. (deepdyve.com)
- The proposed method greatly simplifies the implementation of the (joint) frailty models and makes them much more accessible to general statistical practitioners. (northwestern.edu)
Logarithm of the hazard1
- The Cox model can be written as a multiple linear regression of the logarithm of the hazard on the variables \(x_i\) , with the baseline hazard being an 'intercept' term that varies with time. (sthda.com)
Shape of the hazard2
- We show, based on an exogenous information process, that the way traders aggregate information has implications for the shape of the hazard function. (uni-konstanz.de)
- assumes parametric form for the effect of the predictors on the hazard In most situations, we are more interested in the parameter estimates than the shape of the hazard. (oftavisionhealth.com.br)
Mathematics1
- Mathematics & Statistics (Sci) : Distribution theory, stochastic models and multivariate transformations. (mcgill.ca)
Piecewise2
- We approximate the unspecified baseline hazard by a piecewise constant one, resulting in a parametric model that can be fitted conveniently by Gaussian quadrature tools in standard software such as SAS Proc NLMIXED. (northwestern.edu)
- I need an expert in R who knows cox proportional hazard model to help fit a piecewise exponential baseline hazard. (freelancer.com)
Probability4
- Hi, I am analyzing the influence of some variables on the probability of failure in the sample of firms using parametric survival model in STATA. (stata.com)
- We propose a deep model for computed-tomography-based survival analysis providing a hazard probability output representation comparable to Cox regression without relying on the hazard proportionality assumption. (springer.com)
- The Cox proportional hazard model is used to compare the forecasting power of Bharath and Shumway's naive model, which retains the functional form of the Merton DD model and computes the default probability in a naive way, with our new model, which treats investors' ambiguity aversion as additional information. (mdpi.com)
- The hazard function is the probability that an individual will experience an event (for example, death) within a small time interval, given that the individual has survived up to the beginning of the interval. (xlstat.com)
Additive2
- a) complete case analysis (CC) b) single imputation using regression switching with predictive mean matching (SI), c) multiple imputation using regression switching imputation, d) multiple imputation using regression switching with predictive mean matching (MICE-PMM) and e) multiple imputation using flexible additive imputation models. (ebscohost.com)
- Instrumental variable additive hazards models. (deepdyve.com)
Confidence intervals1
- Participants will be assumed to have some knowledge of elementary statistical techniques (e.g. hypothesis testing, standard errors and confidence intervals) and linear regression (e.g. concept of a statistical model, comparing models). (jiscmail.ac.uk)
Statistical models3
- This article reports age-standardised rates of death involving the coronavirus (COVID-19) by religious group and uses statistical models to adjust for location, measures of disadvantage, occupation, living arrangements, and pre-existing health conditions. (ons.gov.uk)
- Statistical Models Based on Counting Process. (sciencepublishinggroup.com)
- 1999) Variation over Time of the Effects of Prognostic Factors in a Population based Study of Colon Cancer: Comparison of Statistical Models. (bsijournal.org)
Strata2
- separate baseline hazard functions are fit for each strata. (psu.edu)
- Although the Cox model makes no assumptions about the distribution of failure times, it does assume that hazard functions in the different strata are proportional over time - the so-called proportional hazards assumption. (oftavisionhealth.com.br)
19722
- Cox proportional-hazards model is developed by Cox and published in his work[1] in 1972. (oftavisionhealth.com.br)
- The subject of this appendix is the Cox proportional-hazards regression model introduced in a seminal paper by Cox, 1972, a broadly applicable and the most widely used method of survival analysis. (oftavisionhealth.com.br)
Multivariate1
- This generalizes the usual frailty model by allowing a multivariate random effect with arbitrary design matrix in the log relative risk, in a way similar to the modelling of random effects in linear, generalized linear and non-linear mixed models. (sciencenest.com)
Coefficients4
- In the simplest case of stationary coefficients, for example, a treatment with a drug may, say, halve a subject's hazard at any given time t {\displaystyle t} , while the baseline hazard may vary. (wikipedia.org)
- A Cox proportional hazards model was fitted to each dataset and estimates for the regression coefficients and model performance measures obtained. (ebscohost.com)
- Interpreting a Cox model involves examining the coefficients for each explanatory variable. (xlstat.com)
- The fitted model based on three different hazard function revealed, that estimates of the regression coefficients and their relevant standard error are quit close when h2(t) and h3(t) are used as hazard rate. (pjsor.com)
Function13
- Cox proposed an ingenious principle for estimating all proportional hazard models without knowing the function h(t) or even the base hazard rate h 0 (t). (statistics.com)
- The survival analysis allows to combine information from live (censored) and culled (uncensored) animals to model the nonlinear, the time-dependent factors influencing productive life, and describe of the evolution of a hazard function throughout the cow productive life ( Ducrocq, 2005 Ducrocq, V. 2005. (scielo.br)
- This paper puts a focus on the hazard function of inter-trade durations to characterize the intraday trading process. (uni-konstanz.de)
- The Cox proportional hazards model is called a semi-parametric model, because there are no assumptions about the shape of the baseline hazard function. (oftavisionhealth.com.br)
- Because there are no assumptions about the shape of the baseline hazard function must satisfy baseline. (oftavisionhealth.com.br)
- The Cox model is expressed by the hazard function denoted by h(t). (sthda.com)
- Briefly, the hazard function can be interpreted as the risk of dying at time t. (sthda.com)
- A separate estimator of the baseline hazard function is provided. (elsevier.com)
- Displays diagnostics graphs presenting goodness of Cox Proportional Hazards Model fit, that can be calculated with coxph function. (datanovia.com)
- A function to create a regular grid over an observation window in order to model the spatial randome effects as a Gaussian Markov random field. (rdrr.io)
- 3.5 Estimating the Survival Function of the Proportional Hazards Regression Model. (wiley.com)
- Survival pattern can be conveniently inspected with the help of hazard function. (pjsor.com)
- Three different forms of the hazard rates are incorporated in the hazard function and are tried out as response. (pjsor.com)
Discrete2
- Discrete proportional hazards models for mismeasured outcomes. (semanticscholar.org)
- An extensive simulation study is conducted to examine the empirical performance of the parameter estimates under the Cox proportional hazards model by treating discrete survival times as continuous survival times, and the model comparison criteria, AIC and BIC, in determining links and baseline hazards. (elsevier.com)
Survival times1
- 3.4 Fitting the Proportional Hazards Model with Tied Survival Times. (wiley.com)
Time dependent1
- The proportional hazards model included time-dependent effects of herd-year-season contemporary group and parity by stage of lactation interaction, as well as time-independent effects of sire and age at first calving. (pubfacts.com)
Parameter2
- To avoid this mean adjustment, we can manually generate the predicted log of hazard using the parameter estimates as shown below. (ucla.edu)
- Other HR models have different formulations and the interpretation of the parameter estimates differs accordingly. (wikipedia.org)
Dantzig1
- The Dantzig selector for the proportional hazards model proposed by D.R. Cox is studied in a high-dimensional and sparse setting. (elsevier.com)
Assumptions1
- A semi-parametric model, because there are no assumptions about the shape the! (oftavisionhealth.com.br)
Gompertz1
- In the Gompertz model, birthplace and age at onset of the disease were significant factors (p= 0.035, and p= 0.005) in survival time. (ac.ir)
Cohort2
Exponential distribution1
- 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. (stackexchange.com)
Functions1
- Basic quantifiers of survival: survival, hazard and cumulative hazard functions. (york.ac.uk)
Predictive3
- Campbell, Hilscher and Szilagyi [ 2 ] concluded that the strong predictive power of the Merton DD model came from the functional form imposed by the Merton model. (mdpi.com)
- in predictive modelling applications, correction is neither necessary nor appropriate. (wikipedia.org)
- In predictive modelling, no. (wikipedia.org)
Logistic Regression1
- begingroup$ @seanv507 Yes, I'm very new to Survival analysis as explained, I'm even considering doing a Logistic Regression for each period, but I also would like to learn more about Survival models. (stackexchange.com)
Hypothesis2
- When the proportional hazards hypothesis does not hold, the model can be stratified. (xlstat.com)
- This course begins with an overview and continues to cover the following topics: summary statistics and exploratory graphics, simple hypothesis testing, regression modelling using the Cox model and some extensions to this model. (jiscmail.ac.uk)
Predict5
- It also shows how to fit a Cox proportional hazards (PH) model, also known as Cox regression, to predict PDs. (mathworks.com)
- In survival analysis several regression modeling strategies can be applied to predict the risk of future events. (sciencepublishinggroup.com)
- Clinical prediction models aim to predict outcomes in individuals, to inform diagnosis or prognosis in healthcare. (bmj.com)
- 8 9 Such models allow health professionals to predict an individual's outcome value, or to predict an individual's risk of an outcome being present (diagnostic prediction model) or developed in the future (prognostic prediction model). (bmj.com)
- Use of FLIM histology-based HER2-HER3 heterodimer quantification and a Bayesian latent class proportional hazards model to predict cetuximab response in the COIN and new EPOC trials. (ox.ac.uk)