392,317 papers found

BACKGROUND: Constipation is a frequent gastrointestinal symptom. It is intimately related to many diseases. 1st-line therapy can not alleviate constipation for some patients. Alternative treatments are therefore commonly used, such as probiotics. Nevertheless, the efficacy and safety of probiotics used as a single trea…

BACKGROUND: Various studies have explored the association between outdoor air pollution and semen quality. However, the results were still controversial. The object of the current meta-analysis is to evaluate the role of outdoor air pollution in semen quality. METHODS: Databases including PubMed, Web of Science, and E…

BACKGROUND: Type 2 diabetes is one of the most common and complex chronic disease. A lot of clinical researches have focused on meditative movement for type 2 diabetes. However, there is no systematic review and meta-analysis has been conducted. We aim to systematically review the effect of meditative movement on the t…

Multiple imputation is a popular method for addressing missing data, but its implementation is difficult when data have a multilevel structure and one or more variables are systematically missing. This systematic missing data pattern may commonly occur in meta-analysis of individual participant data, where some variabl…

OBJECTIVE: Complete, accurate reporting of systematic reviews facilitates assessment of how well reviews have been conducted. The primary objective of this study was to examine compliance of systematic reviews in veterinary journals with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidel…

Model-based meta-analysis (MBMA) is increasingly used in drug development to inform decision-making and future trial designs, through the use of complex dose and/or time course models. Network meta-analysis (NMA) is increasingly being used by reimbursement agencies to estimate a set of coherent relative treatment effec…

The usefulness of meta-analysis has been recognized in the evaluation of drug safety, as a single trial usually yields few adverse events and offers limited information. For rare events, conventional meta-analysis methods may yield an invalid inference, as they often rely on large sample theories and require empirical…

To deliver high-quality clinical care to patients with diabetes and other chronic conditions, clinicians must understand the evidence available from studies that have been performed to address important clinical management questions. In an evidence-based approach to clinical care, the evidence from clinical research sh…

The increase in treatment options creates an urgent need for comparative effectiveness research. Randomized, controlled trials comparing several treatments are usually not feasible, so other methodological approaches are needed. Meta-analyses provide summary estimates of treatment effects by combining data from many st…

Safety analysis to estimate the effect of a treatment on an adverse event poses a challenging statistical problem even in randomized controlled trials because these events are typically rare, so studies originally powered for efficacy are underpowered for safety outcomes. A meta-analysis of data pooled across multiple…

Absence of a perfect reference test is an acknowledged source of bias in diagnostic studies. In the case of tuberculous pleuritis, standard reference tests such as smear microscopy, culture and biopsy have poor sensitivity. Yet meta-analyses of new tests for this disease have always assumed the reference standard is pe…

In medical meta-analysis, the DerSimonian-Laird confidence interval for the average treatment effect has been widely adopted in practice. However, it is well known that its coverage probability (the probability that the interval actually includes the true value) can be substantially below the target level. One particul…

The main goal of meta-analysis is to combine data across studies or data sets to obtain summary estimates. In this paper, the novelty is to propose a statistical tool to assess a possible covariate imbalance in baseline variables to investigate similarity of trials. We conducted the detection of the covariate imbalance…

Yu et al. (Breast Cancer Res Treat 117:675-677, 2009) recently stated that testing for deviation from Hardy-Weinberg equilibrium (HWE) is necessary to identify systematic genotyping errors in case-control studies. They criticized a meta-analytic study for the deviation from HWE in the case group of one study. The aim o…

BACKGROUND: Individual structural imaging studies in the pre-psychotic phases deliver contrasting findings and are unable to definitively characterize the neuroanatomical correlates of an increased liability to psychosis and to predict transition to psychosis. METHOD: Ninenteen voxel-based morphometry (VBM) studies of…

Meta-analysis is a useful tool to increase the statistical power to detect gene-disease associations by combining results from the original and subsequent replication studies. Recently, consortium-based meta-analyses of several genome-wide association (GWA) data sets have discovered new susceptibility genes of common d…

Meta-analysis of randomized controlled trials is considered to be the methodology that provides the most solid scientific basis for constructing clinical guidelines. It involves systematically collecting the results of similar studies that were conducted to verify similar medical hypotheses and combining these results…

Common methodologies used in systematic reviews do not allow adequate appraisal of complex interventions. The aim of the present study was to describe and critically appraise current methods of systematic reviews on complex interventions, using diabetes and hypertension patient education as examples. PubMed, the Cumula…

In traditional epidemiological studies the association between phenotype (risk factor) and disease is often biased by confounding and reverse causation. As a person's genotype is assigned by a seemingly random process, genes are potentially useful instrumental variables for adjusting for such bias. This type of adjustm…

Genetic association studies have the potential to advance our understanding of genotype-phenotype relationships, especially for common, complex diseases where other approaches, such as linkage, are less powerful. Unfortunately, many reported studies are not replicated or corroborated. This lack of reproducibility has m…