392,317 papers found

PURPOSE: To report the findings from a critical appraisal concerning the credibility of a meta-analysis (M-A) about the role of dietary soy intake in reducing breast cancer risk. The use of an evidence-based, advanced nursing practice framework was used to appraise the M-A. APPROACH: The clinical question was develope…

The working memory (WM) concept has stimulated substantial research since Baddeley and Hitch advanced their model in 1974. There has also been growing interest in WM in Parkinson's disease (PD) where the brain structures considered important for WM are often compromised. However, it remains unclear how and to what degr…

BACKGROUND: Simpson's paradox is sometimes referred to in the areas of epidemiology and clinical research. It can also be found in meta-analysis of randomized clinical trials. However, though readers are able to recalculate examples from hypothetical as well as real data, they may have problems to easily figure where i…

BACKGROUND AND OBJECTIVE: Cumulative meta-analyses are prone to produce spurious P<0.05 because of repeated testing of significance as trial data accumulate. Information size in a meta-analysis should at least equal the sample size of an adequately powered trial. Trial sequential analysis (TSA) corresponds to group seq…

Meta-analysis in its present form of statistically integrating information from several studies all with a common underlying theme has been around for over 25 years. The medical field has seen many attempts by many investigators to pull summary data together from various sources within a discipline with the goal of mak…

Oxidative stress has long been suggested to participate in the pathophysiology of schizophrenia. Most of the published data on the subject rely on malondialdehyde levels assessment through thiobarbituric acid reactive substances (TBARS), despite significant methodological concerns. The present paper reports on a meta-a…

CONTEXT: Egger's regression test is often used to help detect publication bias in meta-analyses. However, the performance of this test and the usual funnel plot have been challenged particularly when the summary estimate is the natural log of the odds ratio (lnOR). OBJECTIVE: To compare the performance of Egger's regr…

The general methodology, strengths and weaknesses, and political uses of meta-analysis are examined. As a systematic study of all studies that have been conducted to answer a specific question or hypothesis, meta-analysis is strong in revealing structural flaws and sources of bias in primary research and in posing prom…

OBJECTIVE: In the last 10 years, health sciences literature has seen a significant increase in papers that report findings of meta-analyses. Meta-analysis overcomes the weakness of conventional narrative literature review. Moreover, it has established itself as a significant tool in clinical research and evidence-based…

Meta-analyses using individual patient data are becoming increasingly common and have several advantages over meta-analyses of summary statistics. We explore the use of multilevel or hierarchical models for the meta-analysis of continuous individual patient outcome data from clinical trials. A general framework is deve…

Three approaches for estimating the relationship between treatment effect and underlying risk in a meta-analysis of clinical trials have recently been published. The aim of each is to overcome the bias inherent in conventional regressions of treatment effect on control group risk, which arises from the measurement erro…

Literature analyses and syntheses are becoming increasingly important as a means of periodically bringing coherence to a research area, contributing new knowledge revealed by integrating single studies, and quickly informing scientists of the state of the field. As a result, there is a need for approaches that can prov…

A review of 150 published randomized trials on the treatment of lung cancer showed serious methodological drawbacks. Handling of withdrawals (only 7 trials had no dropouts), a priori estimates of sample size (only 9 trials specified the required number of patients), blinding of randomization (only 22 trials had a satis…

The data of the Collaborative Behavioral Teratology Study (CBTS) were analyzed. Population-effect sizes were estimated, in terms of confidence intervals, by meta-analysis. A treatment effect of methylmercury was clearly observed and a dose-response effect was also observed. On the other hand, no clear treatment effect…

INTRODUCTION: Timing of cord clamping and other cord management strategies may improve outcomes at preterm birth. However, it is unclear whether benefits apply to all preterm subgroups. Previous and current trials compare various policies, including time-based or physiology-based deferred cord clamping, and cord milkin…

BACKGROUND: Hearing loss is one of the leading causes of disability worldwide, with greater than 20% of Canadian adults having measurable hearing loss in at least one ear. Patients with hearing loss experience impaired quality of life, and emotional and financial consequences that affect themselves and their families.…