392,419 papers found

BACKGROUND: Clinical researchers have often preferred to use a fixed effects model for the primary interpretation of a meta-analysis. Heterogeneity is usually assessed via the well known Q and I2 statistics, along with the random effects estimate they imply. In recent years, alternative methods for quantifying heteroge…

Meta-analysis seeks to combine the results of several experiments in order to improve the accuracy of decisions. It is common to use a test for homogeneity to determine if the results of the several experiments are sufficiently similar to warrant their combination into an overall result. Cochran's Q stati…

To examine the nature of the association between depression and obesity and to determine possible underlying (demographic) factors, we conducted a meta-analysis of cross-sectional studies in the general population. We searched in major bibliographical databases (PubMed, Embase and PsycInfo) for studies examining the as…

Literature data are often reported as multiple (longitudinal) mean outcomes observed in several groups of patients within a study. Observations within a study are correlated because the patients come from a common population, and the mean observations over time within a treatment arm are correlated because they are bas…

BACKGROUND: A cumulative meta-analysis of successive randomized controlled trials (RCTs) can be used to decide whether enough evidence has been obtained comparing a control and an intervention treatment or whether a new RCT should be initiated. In general, no adjustment is made for repeatedly testing the null hypothesi…

Data from multiple genome-wide association studies are often analyzed together for the purposes of combining information from several studies of the same disease or comparing results across different disorders. We provide a valid and efficient approach to such meta-analysis, allowing for overlapping study subjects. The…

BACKGROUND: Despite frequent skin involvement with solid tumors, zosteriform metastases are a rare, not well-defined entity, with only few cases published in literature. The unifying characteristic is merely topographic: cutaneous lesions were distributed along dermatomes, despite the variety of clinical features, incl…

The quantile approximation method has recently been proposed as a simple method for deriving confidence intervals for the treatment effect in a random effects meta-analysis. Although easily implemented, the quantiles used to construct intervals are derived from a single simulation study. Here it is shown that altering…

The methylenetetrahydrofolate reductase (MTHFR) gene variant C677T is suspected to be a risk factor for psychiatric disorders, but it remains uncertain whether the MTHFR C677T variant is associated with bipolar disorders. To investigate possible association, unrelated controls (n=461) with no history of psychiatric dis…

Rare cardiovascular events of commonly used drugs are important to document and investigate, but single trials are notoriously underpowered to provide conclusive evidence. Recently, meta-analyses have been used to improve on the power. A recent rosiglitazone meta-analysis heightened the debate about the usefulness and…

This study is a comparative analysis and meta-analysis of three randomized clinical trials. Children with spastic diplegia received either 'selective' dorsal rhizotomy (SDR) plus physiotherapy (SDR+PT) or PT without SDR (PT-only). Common outcome measures were used for spasticity (Ashworth scale) and function (Gross Mot…

Meta-analysis offers the opportunity to combine evidence from retrospectively accumulated or prospectively generated data. Meta-analyses may provide summary estimates and can help in detecting and addressing potential inconsistency between the combined datasets. Application of meta-analysis in genetic associations pres…

The combination of results from different large-scale datasets of multidimensional biological signals (such as gene expression profiling) presents a major challenge. Methodologies are needed that can efficiently combine diverse datasets, but can also test the extent of diversity (heterogeneity) across the combined stud…

Meta-analysis of population-based genetic association studies is often challenged by obstacles associated with the underlying inheritance model. For a simple genetic variant with two alleles, a recessive, dominant or co-dominant model is typically assumed. In the absence of a strong biological rationale for a particula…

OBJECTIVE: To predict the screening performance for 17 policies currently in use or being considered for the near future. METHODS: Multivariate Gaussian modeling using parameters derived from published meta-analyses and new meta-analyses for gestation-specific nuchal translucency and between trimester correlations. R…

This study reports an activation likelihood estimation (ALE) meta-analysis of imaging studies of chronic developmental stuttering in adults. Two parallel meta-analyses were carried out: (1) stuttered production in the stutterers; (2) fluent production in the control subjects. The control subjects' data replicated previ…

BACKGROUND: Wise et al. introduced a rank-based statistical technique for meta-analysis of genome scans, the Genome Scan Meta-Analysis (GSMA) method. Levinson et al. recently described two generalizations of the GSMA statistic: (i) a weighted version of the GSMA statistic, so that different studies could be ascribed di…

Possible solutions to the problems of clinical heterogeneity of outcome measures and inadequate reporting of results for randomized controlled trials (RCTs) on carpal tunnel syndrome (CTS) are presented. Meta-analysis was impeded by these problems in 2 systematic reviews concerning conservative and surgical treatment o…

The intricate nature of complex genetic traits dictates that novel methodologies be developed and utilized to achieve better power, better accuracy, and more favorable balance between type I and type II errors than could be achieved by the traditional methods as they are used in mapping Mendelian traits. Meta-analysis…

There exists a variety of situations in which a random effects meta-analysis might be undertaken using a small number of clinical trials. A problem associated with small meta-analyses is estimating the heterogeneity between trials. To overcome this problem, information from other related studies may be incorporated int…