Meta-analysis in medicine.

ABSTRACT

When it comes to health care, everybody - medical professionals, policymakers and patients - wants to know what works and what does not. Every day clinicians debate, implicitly or explicitly, whether new research findings are convincing enough to change the way they practice. The quality of research varies, and so much information is being produced that it is impossible for anyone to know and evaluate it all. Traditionally, randomized controlled trials are considered gold standard study designs. However, if they report discordant results and generate controversies, then what should we look for? The answer to this imbroglio is meta-analysis. Steps in designing and conducting meta-analysis involve describing the purpose of meta-analysis, designing a research question, searching for studies, specifying study selection (inclusion and exclusion) and appraisal criteria, deciding data extraction procedures (including statistical reanalysis), assessing combinability of studies, selecting an analytical strategy (use of models and sensitivity analysis), anticipating systematic errors (biases) and limitations, and presenting and disseminating results of the meta-analysis. The Cochrane Collaboration is significantly contributing to the development of this area of research and making a noticeable dent on the practice of evidence based medicine across the globe. Meta-analytic approaches have been used to resolve long standing controversies in the field of medicine, including dermatology.