382,077 papers found

In recent years, genome-wide association studies (GWAS) have identified many loci that are shared among common disorders and this has raised interest in pleiotropy. For performing appropriate analysis, several methods have been proposed, e.g. conducting a look-up in external sources or exploiting GWAS results by meta-a…

During the last decade, several meta-analytic studies employing different methodological approaches have had inconsistent conclusions regarding antidepressant efficacy. Herein, we aim to comment on methodological aspects that may have contributed to disparate findings. We initially discuss methodological inconsistencie…

MOTIVATION: Sharing genomic data is crucial to support scientific investigation such as genome-wide association studies. However, recent investigations suggest the privacy of the individual participants in these studies can be compromised, leading to serious concerns and consequences, such as overly restricted access t…

Coordinate based meta-analysis (CBMA) is widely used to find regions of consistent activation across fMRI studies that have been selected for their functional relevance to a given hypothesis. Only reported coordinates (foci), and a model of their spatial uncertainty, are used in the analysis. Results are clusters of fo…

Deviations from Hardy-Weinberg equilibrium (HWE) in control subjects may bias the estimates of genetic effects in genetic association studies (GAS) and meta-analysis. A large empirical evaluation was carried out to evaluate the impact of HWE deviation and explore the effect of variance adjustment for the allele-based o…

Individual genome-wide association studies have only limited power to find novel loci underlying complex traits and common diseases. With relatively modest sample and effect sizes, a true association between genotype and phenotype may never meet genome-wide statistical significance (P < 5 x 10(-8)) in a single study. T…

The problem of combining information from separate trials is a key consideration when performing a meta-analysis or planning a multicentre trial. Although there is a considerable journal literature on meta-analysis based on individual patient data (IPD), i.e. a one-step IPD meta-analysis, versus analysis based on summa…

The paper considers meta-analysis of diagnostic studies that use a continuous score for classification of study participants into healthy or diseased groups. Classification is often done on the basis of a threshold or cut-off value, which might vary between studies. Consequently, conventional meta-analysis methodology…

In a meta-analysis combining survival data from different clinical trials, an important issue is the possible heterogeneity between trials. Such intertrial variation can not only be explained by heterogeneity of treatment effects across trials but also by heterogeneity of their baseline risk. In addition, one might exa…

Microarray profiling of gene expression is a powerful tool for discovery, but the ability to manage and compare the resulting data can be problematic. Biological, experimental, and technical variations between studies of the same phenotype/phenomena create substantial differences in results. The application of conventi…

A Bayesian model-based clustering approach is proposed for identifying differentially expressed genes in meta-analysis. A Bayesian hierarchical model is used as a scientific tool for combining information from different studies, and a mixture prior is used to separate differentially expressed genes from non-differentia…

BACKGROUND: This study examined the persistence of attention deficit hyperactivity disorder (ADHD) into adulthood. METHOD: We analyzed data from published follow-up studies of ADHD. To be included in the analysis, these additional studies had to meet the following criteria: the study included a control group and it wa…

BACKGROUND & OBJECTIVE: Previous researches showed that human papillomavirus (HPV) infection was closely related to tumorigenesis of oral squamous cell carcinoma (OSCC). But the results of these studies have great differences because of different research methods. This study was to evaluate synthetically the relationsh…

In meta-analysis of clinical trials published in the medical literature it is customary to restrict oneself to standard univariate fixed or random effects models. If multiple endpoints are present, each endpoint is analysed separately. A few articles have been written in the statistical literature on multivariate metho…

Accurate and complete safety data are indispensable for the proper evaluation of the benefit-to-harm ratio of medical interventions. We evaluated whether a systematic review and meta-analysis of standardized safety data is feasible by requesting information on side effects directly from the investigators of all 38 anti…

Meta-analysis is an important tool in linkage analysis. The pooling of results across primary linkage studies allows greater statistical power to detect quantitative-trait loci (QTLs) and more-precise estimation of their genetic effects and, hence, yields conclusions that are stronger relative to those of individual st…

The randomized clinical trial is the gold standard methodology for evaluating treatment interventions. The randomized trial is a prospective experimental study, the embodiment of the scientific method applied to the clinic. Both organizational and ethical considerations encourage the use of formal criteria for terminat…

Although they usually claim a very thorough search to retrieve every pertinent work, most meta-analyses published in English restrict their search to papers which were also published in English. We reviewed all the meta-analyses printed from 1 January 1991 to 1 April 1993 in 8 medical journals published in English and…

This paper presents a systematic overview or meta-analysis of 54 randomized clinical trials testing a variety of chemotherapeutic approaches in advanced ovarian carcinoma. Prolonged follow-up data are available for most patients and individual patient data were made available for all patients; analysis was made on the…