382,525 papers found

Making sense of a neuroimaging literature that is growing in scope and complexity will require increasingly sophisticated tools for synthesizing findings across studies. Meta-analysis of neuroimaging studies fills a unique niche in this process: It can be used to evaluate the consistency of findings across different la…

Recently, mixed treatment comparisons (MTC) have been presented as an extension of traditional meta-analysis by including multiple different pairwise comparisons across a range of different interventions. MTC allow for indirect comparisons and can therefore provide very useful information for clinical and reimbursement…

Dopamine D3 receptor (DRD3) binds antipsychotic drugs and is abundant in the limbic system of the brain. It has been shown to play important roles in schizophrenia. A number of studies investigated the Ser9Gly polymorphism of the DRD3 gene to test its possible association with schizophrenia; however, the results were i…

OBJECTIVES: The corpus callosum plays a pivotal role in inter-hemispheric transfer and integration of information. Magnetic resonance studies have reported callosal abnormalities in schizophrenia but findings have been inconsistent. Uncertainty has persisted despite a meta-analytic evaluation of this structure several…

We present a meta-analysis procedure for genome-wide linkage studies (MAGS). The MAGS procedure combines genome-wide linkage results across studies with possibly distinct marker maps. We applied the MAGS procedure to the simulated data from the Genetic Analysis Workshop 14 in order to investigate power to detect linkag…

Epidemiologists have gradually come to realize that repeated testing of 'causal' hypotheses normally results in inconsistent outcomes. Contradictory results pop up often enough to arouse suspicion that central epidemiological paradigms may be invalid. In this paper, we introduce complexity to explain inconsistency. Lin…

The results of meta-analysis regarding survival benefit in adjuvant chemotherapy for gastric cancer are very useful and informative in clinical practice. However, in considering the current status of adjuvant therapy the following items regarding the effects of adjuvant therapy need to be considered: (i) the assessment…

In a meta-analysis of randomized controlled trials with time-to-event outcomes, an aggregate data approach may be required for some or all included studies. Variation in the reporting of survival analyses in journals suggests that no single method for extracting the log(hazard ratio) estimate will suffice. Methods are…

AIMS: This paper highlights the lack of consideration that is given to power in the health and social sciences, which is a continuing problem with both single study research and more importantly for meta-analysis. BACKGROUND: The power of a study is the probability that it will lead to a statistically significant resu…

BACKGROUND: Calculation of numbers needed to treat (NNT) is more complex from meta-analysis than from single trials. Treating the data as if it all came from one trial may lead to misleading results when the trial arms are imbalanced. DISCUSSION: An example is shown from a published Cochrane review in which the benefi…

Bayesian modeling offers an elegant approach to meta-analysis that efficiently incorporates all sources of variability and relevant quantifiable external information. It provides a more informative summary of the likely value of parameters after observing the data than do non-Bayesian approaches. This leads to direct p…

Patients treated for cancer with chemotherapy and other cytoreductive therapy often develop serious bacterial, viral, and fungal infections due to B- and T-cell depletion, neutropenia and decreased barrier function of mucosal membranes. In patients with neutropenic fever not responding to broad spectrum antibiotic ther…

The standard approach to inference for random effects meta-analysis relies on approximating the null distribution of a test statistic by a standard normal distribution. This approximation is asymptotic on k, the number of studies, and can be substantially in error in medical meta-analyses, which often have only a few s…

Meta-analysis is a quantitative method available to epidemiologists, psychologists, social scientists and others who wish to produce a summary measure of the effect of exposure on disease, based on results from published studies along with a summary measure of uncertainty. The magnitude of the effect vary from study to…

AIMS: To investigate the characteristics of published trials in order to establish the origin of the differing results obtained in trials of platelet inhibitors after peripheral bypass procedures. METHODS: Analysis of the information from 11 randomised, controlled trials of platelet inhibitors after peripheral bypass…

BACKGROUND: Meta-analysis, the systematic and quantitative synthesis of evidence, has developed considerably in the 1990s and is emerging as an important methodology in medical decision making. As a research methodology, meta-analysis has benefits and limitations that must be acknowledged in its application. EXAMPLES…

Meta-analysis is used to statistically pool the results from individual studies, usually randomised trials, to obtain an estimate of the summary effect size across studies. The summary measure from a meta-analysis is often used to derive the probability of treatment success in a cost-effectiveness analysis. Recently, L…

We propose a process for evaluating quantities of clinical and statistical interest in cumulative meta-analysis. We use Monte Carlo simulation studies to assess the error variance of the time to significance in cumulative meta-analysis. For the specific cumulative meta-analyses that we simulated, the 95% confidence int…

Statistical methods are available for performing a meta-analysis when the response variable of interest is the same in each study. Problems arise when studies exploring a common therapeutic question use different patient response types. This article presents statistical methods for combining studies which involve diffe…

1. A meta-analysis has been performed on nine placebo controlled trials of vigabatrin (GVG) administered as add-on therapy to patients suffering from drug resistant epilepsy. 2. There were two pilot placebo-controlled dose ranging studies, six double-blind crossover studies and a multicentre response controlled study.…