RESUMEN
A systematic review is a carefully planned and conducted study designed to answer a specific focused clinical question. A systematic review differs from the frequently encountered narrative review article. Systematic review must be completed using a prespecified methodology. The reader must ask eight important questions when reading a systematic review: (i) did the review address a focused clinical question (ii) is it likely that important, relevant studies are missed (iii) were the inclusion criteria used to select appropriate articles (iv) was the validity of the included studies assessed (v) were the assessments of studies reproducible (vi) were the results similar from study to study (vii) what were the overall results and how precise are they and (viii) will the results help in caring for patients. The article also provides sources for systematic reviews.