Evidence-based medicine, part 2. An introduction to critical appraisal of articles on therapy.

This article provides an introductory step-by-step process to appraise a therapeutic article. The authors introduce these principles using a systematic approach and case-based format. The process of assessing the validity of a therapeutic article, determining its importance, and applying it to an individual patient is reviewed. The concepts of randomization, blinding, and concealment are discussed to help physicians determine an article's validity. Instruction on calculating relative risk reduction, absolute risk reduction, and number needed to treat is provided and applied to the clinical scenario. Finally, information that is learned from the previous two steps is applied to patient care. The skills learned from appraising a therapeutic article in the manner outlined provides a basis for life-long learning and improved patient care.