392,419 papers found

Motivated by a meta-analysis of animal experiments on the effect of dietary fat and total caloric intake on mammary tumorigenesis, we explore the use of sandwich estimators of variance with conditional logistic regression. Classical conditional logistic regression assumes that the parameters are fixed effects across al…

Meta-analysis is a procedure to systematically research and collect published and (ideally) unpublished randomized clinical trials (RCTs) of treatments and quantitatively summarise their results, in order to obtain an objective assessment of efficacy. Collaboration between statisticians and clinical experts in the fiel…

Meta-analysis of clinical trial data is an increasingly important method in clinical research, particularly in the field of therapeutic evaluation. This method uses some specific statistical techniques which are not all available on standard packages and therefore require specific developments. This paper describes a p…

Meta-analysis is the quantitative technique of combining results from different studies. There is a variety of procedures available for combining effect measures across epidemiologic studies. None of these methods provides an overall effect estimate when the data are sparse within studies and come from different study…

Meta-analysis is increasingly being used in clinical research. While the meta-analytical algorithms for pooling the results of studies using non-censored end-points are now sufficiently standardized, the management of trials based on censored end-points is still controversial, and specific algorithms of meta-analysis a…

The prevention of lipid-related coronary risk by lipid lowering drugs or diet has been the object of several therapeutic trials. This meta-analysis comprises the 6 available primary prevention trials (representing 30,695 subjects). There was an overall reduction of non-lethal infarcts (-26%) and coronary events (-18%)…

Meta-analysis corresponds to all systematic methods which use statistical techniques for combining results from several independent studies. The aim is to get a consistent estimation of the global effect of a procedure on a specified outcome. The technique allows us to increase the power of statistical testing, and to…

A meta-analysis was conducted on 109 published studies which assessed the outcome of various non-medical treatments for chronic pain. Of these studies, 48 provided sufficient information to calculate effect sizes. The remainder were examined according to proportion of patients rated as improved. Studies were compared a…

Our previous guide to estimating hazard ratios (HRs) from published summary (aggregate) data has become very widely used, but many still have difficulties knowing when and how to apply the methods. Informed by our increased experience of applying them across a range of settings, the queries we have received and results…

Independent meta-analyses on the same topic can sometimes yield seemingly conflicting results. For example, prominent meta-analyses assessing the effects of violent video games on aggressive behavior have reached apparently different conclusions, provoking ongoing debate. We suggest that such conflicts are sometimes pa…

PURPOSE: Conducting meta-analyses is an exciting and rewarding way of summarizing and quantifying the current knowledge, which is also becoming increasingly important in clinical research. There are many articles published on interpreting meta-analysis and specific statistical methods, which makes it challenging to obt…

OBJECTIVES: Judging applicability (relevance) of meta-analytical findings to particular clinical decision-making situations remains challenging. We aimed to describe an evidence synthesis method that accounts for possible uncertainty regarding applicability of the evidence. STUDY DESIGN AND SETTING: We conceptualized…

The increasing urgency for evidence based practice, especially in resource limited settings has inspired many initiatives to this effect. In Africa there is limited skill in research synthesis and the production of systematic reviews. The Centre for the Development of Best Practices in Health, together with the South A…

BACKGROUND: Because of the rising number of scientific publications, it is important to have a means of jointly summarizing and assessing different studies on a single topic. Systematic literature reviews, meta-analyses of published data, and meta-analyses of individual data (pooled reanalyses) are now being published…

The proliferation of omics datasets in public repositories has created unprecedented opportunities for biomedical research but has also posed significant challenges for their integration, particularly due to missing genes and platform-specific discrepancies. Traditional gene expression meta-analysis often focuses on in…

BACKGROUND: Polycystic ovary syndrome is an endocrine disorder that occurs mostly in women of reproductive age and has lifelong effects on their health. METHODS: Randomized controlled clinical trials that met the inclusion criteria were screened by searching multiple databases. Relevant data were extracted, and meta-a…

Both designing a clinical study and drawing conclusions from studies about the effect of treatments require justification of the sample size via judicious choice of the endpoint and power. Such an a priori power calculation limits the chances of mistakenly claiming a lack of clinical significance if no statistically si…

Meta-analysis of longitudinal studies combines effect sizes measured at pre-determined time points. The most common approach involves performing separate univariate meta-analyses at individual time points. This simplistic approach ignores dependence between longitudinal effect sizes, which might result in less precise…

BACKGROUND: Systematic reviews and meta-analyses are important research tools in modern medicine. They serve to condense and clarify large amounts of data into resources that can educate clinicians, enhance patient care, help formulate clinical guidelines, and guide future research endeavors. METHODS: The existing lit…

Whilst recent neuroimaging studies have identified a series of different brain regions as being involved in empathy, it remains unclear concerning the activation consistence of these brain regions and their specific functional roles. Using MKDA, a whole-brain based quantitative meta-analysis of recent fMRI studies of e…