382,938 papers found

BACKGROUND: Many reviews aim to compare numerous treatments and report results stratified by subgroups (eg, by disease severity). In such cases, a network meta-analysis model including treatment by covariate interactions can estimate the relative effects of all treatment pairings for each subgroup of patients. Two key…

BACKGROUND: In a random effects meta-analysis model, true treatment effects for each study are routinely assumed to follow a normal distribution. However, normality is a restrictive assumption and the misspecification of the random effects distribution may result in a misleading estimate of overall mean for the treatme…

DNA aneuploidy is an imbalance of chromosomal DNA content that has been highlighted as a predictor of biological behavior and risk of malignant transformation. To date, DNA aneuploidy in oral potentially malignant diseases (OPMD) has been shown to correlate strongly with severe dysplasia and high-risk lesions that appe…

INTRODUCTION: There are many proven treatments (psychotherapy, pharmacotherapy or their combination) for the treatment of depression. Although there is growing evidence for the effectiveness of combination treatment (psychotherapy + pharmacotherapy) over pharmacotherapy alone, psychotherapy alone or psychotherapy plus…

Network meta-analysis enables comprehensive synthesis of evidence concerning multiple treatments and their simultaneous comparisons based on both direct and indirect evidence. A fundamental pre-requisite of network meta-analysis is the consistency of evidence that is obtained from different sources, particularly whethe…

Meta-analysis using individual participant data (IPD) obtains and synthesises the raw, participant-level data from a set of relevant studies. The IPD approach is becoming an increasingly popular tool as an alternative to traditional aggregate data meta-analysis, especially as it avoids reliance on published results and…

OBJECTIVES: There is no consensus on whether studies with no observed events in the treatment and control arms, the so-called both-armed zero-event studies, should be included in a meta-analysis of randomised controlled trials (RCTs). Current analytic approaches handled them differently depending on the choice of effec…

Diagnostic test accuracy studies typically report the number of true positives, false positives, true negatives and false negatives. There usually exists a negative association between the number of true positives and true negatives, because studies that adopt less stringent criterion for declaring a test positive invo…

To account for between-study heterogeneity in meta-analysis of diagnostic accuracy studies, bivariate random effects models have been recommended to jointly model the sensitivities and specificities. As study design and population vary, the definition of disease status or severity could differ across studies. Consequen…

A variable is 'systematically missing' if it is missing for all individuals within particular studies in an individual participant data meta-analysis. When a systematically missing variable is a potential confounder in observational epidemiology, standard methods either fail to adjust the exposure-disease association f…

This letter comments on the recent meta-analysis by Maximiano-Barreto et al. on empathy subdomains and burnout in nurses. The article makes a valuable contribution by showing that empathy is not uniformly protective: perspective taking may be associated with lower burnout, whereas personal distress and possibly fa…

Platelet-rich plasma (PRP) is commonly used alone or in combination with hyaluronic acid (HA) in the treatment of knee osteoarthritis. A recently published meta-analysis and systematic review compared outcomes between PRP + HA combination therapy and PRP monotherapy. This letter addresses a critical conce…

This commentary is an author response to Yu and colleagues regarding the manuscript entitled 'We address their concern regarding minor errors in our manuscript, our search strategy and assessment of heterogeneity.

When conducting a meta-analysis of standardized mean differences (SMDs), it is common to use Cohen's d, or its variants, that require equal variances in the two arms of each study. While interpretation of these SMDs is simple, this alone should not be used as a justification for assuming equal variances. Until now, res…

A growing number of published articles report estimates from meta-analysis or meta-regression on health state utility values (HSUVs), with a view to providing input into decision-analytic models. Pooling HSUVs is problematic because of the fact that different valuation methods and different preference-based measures (P…

OBJECTIVE: We review the state of the art in meta-analysis and data pooling following the evolution of the statistical models employed. METHODS: Starting from a classic definition of meta-analysis of published data, a set of apparent antinomies which characterized the development of the meta-analytic tools are reconci…

Meta-analysis is a statistical method to compare and combine effect sizes from a pool of relevant empirical studies. It is now a standard approach to synthesize research findings in many disciplines, including medical and healthcare research. This paper is the third paper of a mini-series introducing systematic review…

Monensin is an ionophore widely used in the dairy cattle industry throughout the world. A large volume of clinical trials have been conducted that have explored efficacy for various metabolic, production, and health outcomes. However, the results of the individual studies have in some cases been contradictory and in ot…

An astonishing volume and diversity of evidence is available for many hypotheses in the biomedical and social sciences. Some of this evidence-usually from randomized controlled trials (RCTs)-is amalgamated by meta-analysis. Despite the ongoing debate regarding whether or not RCTs are the 'gold-standard' of evidence, it…

The aim of this article is twofold: to offer an introduction to meta-analysis using correlation coefficients to facilitate greater understanding of meta-analytic findings and to guide those interested in conducting meta-analyses. The authors review calculations for a weighted average effect size, the statistical signif…