392,419 papers found

We propose a new exploratory method for the discovery of partially directed functional networks from fMRI meta-analysis data. The method performs structure learning of Bayesian networks in search of directed probabilistic dependencies between brain regions. Learning is based on the co-activation of brain regions observ…

To explore the role and application of Meta-regression and subgroup analyses to recognize and control the heterogeneity in Meta-analysis, Meta-regression models were established by secondary data to screen the factors resulting heterogeneity, and subgroup analyses were used to compare the change of heterogeneity before…

Consider a meta-analysis of studies with varying proportions of patient-level missing data, and assume that each primary study has made certain missing data adjustments so that the reported estimates of treatment effect size and variance are valid. These estimates of treatment effects can be combined across studies by…

The number of published genetic association studies (GASs) is increasing tremendously due to the availability of mapped single-nucleotide polymorphisms (SNPs) and advances in genotyping technologies. A search in HuGENet illustrates the rapid accumulation of evidence for major diseases. Recently, there has been a lot of…

In comparison to other complex disease traits, alcoholism and alcohol abuse are influenced by the combined effects of many genes that alter susceptibility, phenotypic expression and associated morbidity, respectively. Many genetic studies, in both animal models and humans, have identified genetic intervals containing g…

We focus on the comparison of three statistical models used to estimate the treatment effect in meta-analysis when individually pooled data are available. The models are two conventional models, namely a multi-level and a model based upon an approximate likelihood, and a newly developed model, the profile likelihood mo…

This article shows that the interpretation of the random-effects models used in meta-analysis to summarize heterogeneous treatment effects can have a marked effect on the results from decision models. Sources of variation in meta-analysis include the following: random variation in outcome definition (amounting to a for…

BACKGROUND: Most systematic reviewers aim to perform an intention-to-treat meta-analysis, including all randomized participants from each trial. This is not straightforward in practice: reviewers must decide how to handle missing outcome data in the contributing trials. OBJECTIVE: To investigate methods of allowing fo…

INTRODUCTION: The review and continuous analysis of the present knowledge have always been necessary for scientific and clinical practice advance. This study presents the difference between narrative and systematic reviews, the most important points of meta-analysis, and finishes with detailed description of its phases…

Current meta-analytic methods for diagnostic test accuracy are generally applicable to a selection of studies reporting only estimates of sensitivity and specificity, or at most, to studies whose results are reported using an equal number of ordered categories. In this article, we propose a new meta-analytic method to…

BACKGROUND: To analyze the features of the studies on meta-analysis in psychiatry and assess the effect of these papers on the psychiatric reference textbooks. METHODS: Two researchers reviewed electronic databases Medline and Embase during the period 1977-98, using the key words: clinical trial, randomized observatio…

An important quality of meta-analytic models for research synthesis is their ability to account for both within- and between-study variability. Currently available meta-analytic approaches for studies of diagnostic test accuracy work primarily within a fixed-effects framework. In this paper we describe a hierarchical r…

Interpreting observational epidemiological evidence can involve both the quantitative method of meta-analysis and the qualitative criteria-based method of causal inference. The relationships between these two methods are examined in terms of the capacity of meta-analysis to contribute to causal claims, with special emp…

Serum progesterone measurement has been advocated as a diagnostic tool in the non-invasive diagnosis of ectopic pregnancy. To assess the accuracy of a single serum progesterone measurement in the diagnosis of ectopic pregnancy, a meta-analysis was performed incorporating 26 studies evaluating the performance of single…

Meta-analysis of randomized controlled trials combines information from independent studies that address a similar question to provide more reliable estimates of treatment effects. At the present time, the methodology and usefulness of meta-analysis is under scrutiny. In the first part of this paper, we summarize the l…

The usual meta-analysis of a sequence of randomized clinical trials only considers the difference between two treatments and produces a point estimate and a confidence interval for a parameter that measures this difference. The usual parameter is the log(odds ratio) linked to Mantel-Haenszel methodology. Inference is m…

Meta-analysis is a method of synthesizing evidence from multiple sources. It has been increasingly applied to combine results from randomized trials of therapeutic strategies. Unfortunately there is often variation in the quality of the trials that are included in meta-analyses, limiting the value of combining the resu…

While otitis media is perhaps the most common disease of childhood that receives medical attention, there is little agreement concerning the efficacy of the medical and surgical therapies employed to try to alleviate its symptoms or hasten its natural resolution. Because various surgeries including adenoidectomy, myrin…

A pooled estimate of the magnitude of the benefit and side effects of injectable gold salts in rheumatoid arthritis was computed using meta-analysis based upon available evidence in the literature. Active joint count, grip strength, functional capacity, hemoglobin concentration and erythrocyte sedimentation rate (ESR)…