Abstract
IN BRIEF Metformin, an established therapy for the treatment of type 2 diabetes, has demonstrated safety and effectiveness in the prevention or delay of type 2 diabetes in people at high risk. The Diabetes Prevention Program randomized clinical trial demonstrated that intensive lifestyle intervention and metformin therapy reduced progression to diabetes by 58 and 31%, respectively, compared to placebo in people at risk of type 2 diabetes. Although lifestyle intervention was beneficial in all groups, metformin had a selectively greater effect in those who were more obese, had a higher fasting glucose, had a history of gestational diabetes, or were younger. Long-term effects included an 18% diabetes reduction with metformin compared to placebo over 15 years, a reduction in microvascular complications among those who did not progress to diabetes (without difference among treatment arms), and suggestion by coronary calcium assessment of a possible impact on atherosclerosis in men. Although long-term follow-up to assess later-stage outcomes is underway, current efforts to address gaps in evidence and translation remain of significant public health interest.