376,015 papers found

OBJECTIVE: The current evidence concerning the best treatment option for couples with unexplained and male subfertility is inconclusive. Most studies that have evaluated the effectiveness of treatment options, such as expectant management (EM), intrauterine insemination (IUI), with or without controlled ovarian stimula…

BACKGROUND: Results from published studies on the association of donor or recipient TNF-A -308G/A polymorphism with acute rejection (AR) of renal allograft are inconsistent. We performed a meta-analysis to summarize the possible association. METHODS: Studies were identified by searching PUBMED, EMBASE and Chinese Nati…

Publication bias and related types of small-study effects threaten the validity of systematic reviews. The existence of small-study effects has been demonstrated in empirical studies. Small-study effects are graphically diagnosed by inspection of the funnel plot. Though observed funnel plot asymmetry cannot be easily l…

Haematological malignancies are complex diseases, affecting the entire age spectrum, and having marked differences in presentation, treatment, progression and outcome. Patients have a significant symptom burden and despite treatment improvements for some sub-types, many patients die from their disease. We carried out a…

We consider random effects meta-analysis where the outcome variable is the occurrence of some event of interest. The data structures handled are where one has one or more groups in each study, and in each group either the number of subjects with and without the event, or the number of events and the total duration of f…

BACKGROUND: Dietary patterns, which represent whole-diet and possible food and nutrient interactions, have been linked to the risk of various cancers. However, the associations of these dietary patterns with breast cancer remain unclear. OBJECTIVE: We critically appraised the literature and conducted meta-analyses to…

BACKGROUND: Missing outcome data from randomized trials lead to greater uncertainty and possible bias in estimating the effect of an experimental treatment. An intention-to-treat analysis should take account of all randomized participants even if they have missing observations. PURPOSE: To review and develop imputatio…

BACKGROUND: Cumulative meta-analysis typically involves performing an updated meta-analysis every time when new trials are added to a series of similar trials, which by definition involves multiple inspections. Neither the commonly used random effects model nor the conventional group sequential method can control the t…

BACKGROUND: When multiple endpoints are of interest in evidence synthesis, a multivariate meta-analysis can jointly synthesise those endpoints and utilise their correlation. A multivariate random-effects meta-analysis must incorporate and estimate the between-study correlation (rhoB). METHODS: In this paper we assess…

MOTIVATION: High-throughput microarray technology can be used to examine thousands of features, such as all the genes of an organism, and measure their expression. Two important issues of microarray bioinformatics are first, how to combine the significance values for each feature across experiments with high statistica…

BACKGROUND: Meta-analyses based on individual patient data (IPD) are regarded as the gold standard for systematic reviews. However, the methods used for analysing and presenting results from IPD meta-analyses have received little discussion. METHODS: We review 44 IPD meta-analyses published during the years 1999-2001.…

Meta-analysis provides a structured method for combining results from several studies and accounting for and differentiating between study variables. Numerous food safety consumer research studies often focus on specific behaviors among different subpopulations but fail to provide a holistic picture of consumer behavio…

We propose a class of longitudinal data models with random effects that generalizes currently used models in two important ways. First, the random-effects model is a flexible mixture of multivariate normals, accommodating population heterogeneity, outliers, and nonlinearity in the regression on subject-specific covaria…

OBJECTIVE: To evaluate the results of large clinical trials vs the pooled results of smaller trials. DATA IDENTIFICATION: Meta-analyses with at least 1 "large" study were identified from the Cochrane Pregnancy and Childbirth Database and from MEDLINE (1966-1995). STUDY SELECTION: We used a sample size approach to sel…

Meta-analysis is being increasingly used in therapeutic and clinical research to synthetize data from terminated clinical trials. Meta-analysis provides a powerful tool to objectively combine data in a quantitative manner, unlike the classical general review of literature, which is qualitative and subjective by definit…

Formal literature review and synthesis is an important component of Patient Outcomes Research Teams (PORTs) and the development of clinical practice guidelines supported by the Agency for Health Care Policy and Research (AHCPR). Investigators face unresolved methodological issues and practical problems in carrying out…

The relation of job psychologic demands and decision latitude to four coronary heart disease risk factors (cholesterol, smoking, and systolic and diastolic blood pressures) was tested among 12,555 men in five investigations conducted in the United States during the period 1959-1980 (National Health and Nutrition Examin…