392,549 papers found

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Protective effects of metformin, statins, and antiinflammatory drugs on head and neck cancer: A systematic review. Saka Herrán C, Jané-Salas E, Devesa AE, López-López J. Oral Oncol 2018;85:68-81. SOURCE OF FUNDING: None. TYPE OF DESIGN: Systematic revie…

We consider a Bayesian approach for assessing hypotheses of equivalence in two-arm trials with binary Data. We discuss the development of likelihood, the prior, and the posterior distributions of parameters of interest. We then examine the suitability of a normal approximation to the posterior distribution obtained via…

The investigation of heterogeneity remains an essential but difficult issue in the conduct of meta-analysis. We reviewed standard and graphical methods used to explore heterogeneity in meta-analysis and publications from January 2005 to April 2007 regarding meta-analyses that focused on perinatal health topics. We asse…

The multiple sclerosis (MS) community read recently, with some surprise, the conclusions from a systematic review of the major therapeutic recombinant interferon trials in relapsing-remitting (RR)MS.1 The review stated that: 'their (recombinant interferons) clinical effect beyond 1 year is uncertain and new trials are…

Meta-analyses involving the synthesis of evidence from cluster randomization trials are being increasingly reported. These analyses raise challenging methodologic issues beyond those raised by meta-analyses which include only individually randomized trials. In this paper we review and comment on a selected number of th…

Epidemiological studies, more specifically those related to analytical epidemiology are a major determinant of evidence-based medicine. When classifying the value of the different epidemiological studies, based on their level of causality, cohort studies are ranked higher than case-control studies, mainly due to the fa…

QUESTION: Many of my female patients, those who plan pregnancy or have conceived, are afraid of any intake of caffeine. This often makes their lives miserable during pregnancy. Is this justified scientifically? ANSWER: Motherisk's recent meta-analysis suggests that the risks for miscarriage and fetal growth retardatio…

Are meta-analyses the brave new world, or are the critics of such combined analyses right to say that the biases inherent in clinical trials make them uncombinable? Negative trials are often unreported, and hence can be missed by meta-analysts. And how much heterogeneity between trials is acceptable? A recent major cri…

Randomized trials are effective and usually unbiased for showing the average results in a selected outcome variable for treatment A versus treatment B, and meta-analyses produce an average of these averages. The results of both the trials and meta-analyses are often pragmatically unsatisfactory, however, because they d…

This paper reviews methods for deriving measures of effect for interrupted time-series (single case) designs. Limitations of prior models are described. Modifications of a regression approach developed by Center, Skiba, and Casey (1985-86, Journal of Special Education, 19, 387-400) which can simultaneously account for…

Epidemiological studies on low risks involve a number of major methodological difficulties. This review defines the concept of low risk and emphasises the need to control all large, possibly disease-related risk factors, before low risk factors can be evaluated. This procedure is also essential in identifying confoundi…

Summarizing epidemiologic data from multiple studies can be accomplished either by a meta-analysis of published findings or by pooling data and performing new analyses of enlarged data sets. Meta-analysis is relatively easy and inexpensive to perform but usually is restricted to examination of overall risks. Data pooli…

Science can be seen as a sequential process where each new study augments evidence to the existing knowledge. To have the best prospects to make an impact in this process, a new study should be designed optimally taking into account the previous studies and other prior information. We propose a formal approach for the…

BACKGROUND AND OBJECTIVE: Communicating the results of studies is an important problem. For binary outcomes, communication is relatively straightforward and supported by several statistical tools (e.g., the risk ratio and the number needed to treat [NNT]). For continuous outcomes, the situation is much worse. We discus…