No Cardioprotection Seen With Long-Term Metformin or Lifesty
The original DPP randomized clinical trial kicked off in 1996 and ran for about 3 years. It included 3,234 individuals with prediabetes, defined as impaired glucose tolerance with a fasting plasma glucose 95 to 125 mg/dL (5.27 to 6.94 mmol/L) and BMI 24 or higher. Those who experienced a CV event within the prior 6 months were excluded.

Participants were then randomized to receive 850 mg of metformin twice-daily, placebo twice daily, or lifestyle intervention. The latter program was aimed as a goal of 7% or greater initial body weight reduction with a minimum of 150 minutes per week of moderate intensity physical activity.

After DPP wrapped, all surviving patients were invited to participate in the follow-up DPP Outcomes Study, regardless of their diabetes status. At this point, 68% of the DPP Outcomes Study participants were women with an average age of 51; more than half were white. These participants were followed for an additional 18 years, amounting to a combined median follow-up of 21 years. During this study, unmasked metformin was continued in the metformin group and all participants were offered a less intensive group lifestyle intervention.

During an 18-year follow-up to the landmark DPP trial, treatment with metformin was no better than placebo at reducing the risk of major CV events (MACE; HR 1.03, 95% CI 0.78-1.37, P=0.81).