Additional risk factors in atrial fibrillation patients not receiving warfarin.
(9/1807)
OBJECTIVE: To study how many elderly inpatients with previously diagnosed atrial fibrillation were not receiving anticoagulant prophylaxis, and the prevalence of additional risk factors in these patients. METHODS: All new admissions to a department of medicine for the elderly were screened for atrial fibrillation. Additional risk factors were analysed in those with established atrial fibrillation who were not receiving warfarin. Previous hospital admissions, documentation of why prophylaxis was not being used and use of aspirin as an alternative agent were also examined. RESULTS: 56 patients had previously diagnosed atrial fibrillation; 82% were not taking warfarin and 71% of these were not on aspirin either. All patients not taking warfarin had one additional risk factor for stroke and 95% had two or more. Fifty-two percent had attended hospital when atrial fibrillation was present within the previous 3 years and there was nothing documented in their records to explain why anticoagulation had not been used. CONCLUSIONS: Most elderly inpatients with established atrial fibrillation were not taking warfarin. All had additional risk factors for stroke, which increase the absolute benefit of anticoagulation. (+info)
Random-effects meta-analyses are not always conservative.
(10/1807)
It is widely held that random-effects summary effect estimates are more conservative than fixed-effects summaries in epidemiologic meta-analysis. This view is based on the fact that random-effects summaries have higher estimated variances and, consequently, wider confidence intervals than fixed-effects summaries when there is evidence of appreciable heterogeneity among the results from the individual studies. In such instances, however, the random-effects point estimates are not invariably closer to the null value nor are their p values invariably larger than those of fixed-effects summaries. Thus, random-effects summaries are not predictably conservative according to either of these two connotations of the term. The authors give an example from a meta-analysis of water chlorination and cancer in which the random-effects summaries are less conservative in both of these alternative senses and possibly more biased than the fixed-effects summaries. The discussion of when to use random effects and when to use fixed effects in computing summary estimates should be replaced by a discussion of whether summary estimates should be computed at all when the studies are not methodologically comparable, when their results are discernibly heterogeneous, or when there is evidence of publication bias. (+info)
Decision analysis in nuclear medicine.
(11/1807)
This review focuses primarily on the methodology involved in properly reviewing the literature for performing a meta-analysis and on methods for performing a formal decision analysis using decision trees. Issues related to performing a detailed metaanalysis with consideration of particular issues, including publication bias, verification bias and patient spectrum, are addressed. The importance of collecting conventional measures of test performance (e.g., sensitivity and specificity) and of changes in patient management to model the cost-effectiveness of a management algorithm is detailed. With greater utilization of the techniques discussed in this review, nuclear medicine researchers should be well prepared to compete for the limited resources available in the current health care environment. Furthermore, nuclear medicine physicians will be better prepared to best serve their patients by using only those studies with a proven role in improving patient management. (+info)
Use of meta-analytic results to facilitate shared decision making.
(12/1807)
OBJECTIVES: Describe and evaluate an Internet-based approach to patient decision support using mathematical models that predict the probability of successful treatment on the basis of meta-analytic summaries of the mean and standard deviation of symptom response. DESIGN: An Internet-based decision support tool was developed to help patients with benign prostatic hypertrophy (BPH) determine whether they wanted to use alpha blockers. The Internet site incorporates a meta-analytic model of the results of randomized trials of the alpha blocker terazosin. The site describes alternative treatments for BPH and potential adverse effects of alpha blockers. The site then measures patients' current symptoms and desired level of symptom reduction. In response, the site computes and displays the probability of a patient's achieving his objective by means of terazosin or placebo treatment. SETTING: Self-identified BPH patients accessing the site over the Internet. MAIN OUTCOME MEASURES: Patients' perceptions of the usefulness of information. RESULTS: Over a three-month period, 191 patients who were over 50 years of age and who reported that they have BPH used the decision support tool. Respondents had a mean American Urological Association (AUA) score of 18.8 and a desired drop in symptoms of 10.1 AUA points. Patients had a 40 percent chance of achieving treatment goals with terazosin and a 20 percent chance with placebo. Patients found the information useful (93 percent), and most (71 percent) believed this type of information should be discussed before prescribing medications. CONCLUSIONS: Interactive meta-analytic summary models of the effects of pharmacologic treatments can help patients determine whether a treatment offers sufficient benefits to offset its risks. (+info)
State of the evidence: current status and prospects of meta-analysis in infectious diseases.
(13/1807)
Meta-analysis is increasingly applied in infectious diseases to summarize clinical data and to evaluate the strength, diversity, and deficiencies of evidence for medical questions of interest. We present an overview of the current status of meta-analysis in the area of infectious diseases and the lessons learnt from its applications. Recently published meta-analyses show that several important areas of research on infectious diseases lack sufficient randomized evidence. Often evidence is scattered across a large number of small trials, making meta-analysis a promising way to integrate diverse results. Quality of trials in the field is often poor. There are several examples where evidence was accumulated primarily for marketing rather than for scientific purposes. Finally, meta-analyses are also raising the problem of what constitutes clinically significant treatment benefits, as well as interesting issues about the reproducibility of clinical evidence and its evolving nature. The increasing applications of meta-analytic methods in the study of infectious diseases may enhance data sharing and international collaborations. (+info)
Systematic reviews and meta-analyses on treatment of asthma: critical evaluation.
(14/1807)
OBJECTIVE: To evaluate the clinical, methodological, and reporting aspects of systematic reviews and meta-analyses on the treatment of asthma and to compare those published by the Cochrane Collaboration with those published in paper based journals. DESIGN: Analysis of studies identified from Medline, CINAHL, HealthSTAR, EMBASE, Cochrane Library, personal collections, and reference lists. STUDIES: Articles describing a systematic review or a meta-analysis of the treatment of asthma that were published as a full report, in any language or format, in a peer reviewed journal or the Cochrane Library. MAIN OUTCOME MEASURES: General characteristics of studies reviewed and methodological characteristics (sources of articles; language restrictions; format, design, and publication status of studies included; type of data synthesis; and methodological quality). RESULTS: 50 systematic reviews and meta-analyses were included. More than half were published in the past two years. Twelve reviews were published in the Cochrane Library and 38 were published in 22 peer reviewed journals. Forced expiratory volume in one second was the most frequently used outcome, but few reviews evaluated the effect of treatment on costs or patient preferences. Forty reviews were judged to have serious or extensive flaws. All six reviews associated with industry were in this group. Seven of the 10 most rigorous reviews were published in the Cochrane Library. CONCLUSIONS: Most reviews published in peer reviewed journals or funded by industry have serious methodological flaws that limit their value to guide decisions. Cochrane reviews are more rigorous and better reported than those published in peer reviewed journals. (+info)
Value of radiological diagnosis of skull fracture in the management of mild head injury: meta-analysis.
(15/1807)
OBJECTIVES: Head injury is a common event. Most patients sustain a mild head injury (MHI), and management depends on the risk of an intracranial haemorrhage (ICH). The value of a plain skull radiograph as a screening tool for ICH is controversial. The aim of this meta-analysis was to estimate and explain differences in reported sensitivity and specificity of the finding of a skull fracture for the diagnosis of ICH, in order to assess the value of the plain skull radiograph in the investigation of patients with MHI, and to estimate the prevalence of ICH in these patients. METHOD: After a systematic literature search 20 studies were selected that reported data on the prevalence of ICH after MHI and/or data on the diagnostic value of skull fracture for the diagnosis of ICH. The mean prevalence of ICH weighted for the sample size was determined. The sensitivity and specificity of different studies were combined using a summary receiver operator characteristic curve. Correlation analysis was used to determine factors that could explain the reported differences between studies. RESULTS: The weighted mean prevalence of ICH after MHI is 0.083. The potential for verification bias and the percentage of patients who had suffered loss of consciousness or post-traumatic amnesia were the most significant factors explaining interstudy differences in sensitivity and specificity. Based on studies wherein at least 50% of patients had a CT study of the brain, the estimated sensitivity of a radiographic finding of skull fracture for the diagnosis of ICH is 0.38 with a corresponding specificity of 0.95. CONCLUSION: The plain skull radiograph is of little value in the initial assessment of MHI patients. (+info)
Systematic reviews on leptospirosis.
(16/1807)
OBJECTIVES: To find the existing clinical evidence on interventions for leptospirosis. The objective is to evaluate the effectiveness and safety of any intervention on leptospirosis through systematic reviews of randomized controlled trials (RCTs). DATA SOURCE: The sources of studies used (where there were no limitations concerning language, date, or other restrictions) were: EMBASE, LILACS, MEDLINE, the Cochrane Controlled Clinical Trials Database, and the Cochrane Hepato-Biliary Group Randomized Trials register. SELECTION OF STUDIES: TYPE OF STUDY: All systematic reviews of randomized controlled trials. PARTICIPANTS: patients with clinical and/or laboratorial diagnosis of leptospirosis, and subjects potencially exposed to leptospirosis as defined by the authors INTERVENTIONS: any intervention for leptospirosis (as antibiotics or vaccines for prevention or treatment). DATA COLLECTION: The assessment will be independently made by the reviewers and cross-checked. The external validity was assessed by analysis of: studies, interventions, and outcomes. DATA SYNTHESIS: Located 163 studies using the search strategy described above, at the electronic databases above. Only 2 hits were selected, which are protocols of systematic reviews of Cochrane Collaboration, and not full reviews. One of the protocols evaluates antibiotics for treatment, and the other evaluates antibiotics for prevention of leptospirosis. CONCLUSIONS: There were not complete systematic reviews on interventions for leptospirosis. Any interventions for leptospirosis, such as prevention and treatment remains unclear for guidelines and practice. (+info)