Systematic Review and Meta-analysis

We live in the information age, and the practice of medicine is becoming increasingly specialized. In the biomedical literature, the number of published studies has dramatically increased: There are now more than 15 million citations in MEDLINE, with 10,000 to 20,000 new citations added each week (1). Multiple relevant studies usually guide most clinical decisions. These studies often vary in their design; methodologic quality; population studied; and the intervention, test, or condition considered. Because even highly cited trials may be challenged or refuted over time (2), clinical decision-making requires ongoing reconciliation of studies that provide different answers to the same question. Both clinicians…