Does metformin prevent diabetes in at-risk adults?

Abstract

Metformin therapy reduces the risk of developing diabetes for adults with one or more risk factors for at least 5 years (strength of recommendation [SOR]: A, consistent meta-analyses) and perhaps as long as 10 years (SOR: B, randomized clinical trial [RCT]). Lifestyle modification with diet and exercise is approximately twice as effective as metformin for preventing diabetes, especially in older patients (SOR: B, RCTs).