Systematic Reviews and Meta-Analysis of Therapeutic Interventions: How to Better Understand Them? Revisão Sistemática e Met análise de Intervenções Terapêuticas: Como Melhor Entendê-las?

In th e past decade, the Era of Evidence-Based Medicine, the number of meta-analysis dramatically increased. Metaanalyses statistically combine the results of multiple studies and are considered to be the highest level of evidence when the results of high-quality randomized trials are combined in an appropriate way. Results from a meta-analysis may not correspond to reality because of the large variation in the quality of the studies that have been pooled, and clinical and methodological differences among the included studies. The growing popularity of systematic reviews and meta-analyses has made it important to better understand them. The objective of this article is to help the reader comprehend how a systematic review and meta-analysis is carried out and to be better able to interpret them. We explain some impor tant aspects of conducting a meta-analysis. A better understanding of the basic terminology and the concepts involved in generating a systematic review and meta-analysis may help the clinician better evaluate the quality of a meta-analysis and the real importance of its findings for a specific patient.