Preventing Diabetes With Lifestyle Interventions and Medication

The Diabetes Prevention Program (DPP), a randomized clinical trial published in The Lancet, demonstrated that intensive lifestyle intervention or metformin prevented or delayed development of type 2 diabetes in high-risk adults compared with placebo. The current article is the first report of the Diabetes Prevention Program Outcomes Study (DPPOS), a ten year follow-up designed to determine whether the delay in diabetes seen during the DPP can be sustained.

After being informed of the main DPP results, patients in the metformin and placebo groups entered a 1- to 2-week drug washout phase. All participants were offered a group-administered version of the 16-session lifestyle curriculum as a bridge protocol. Once the DPPOS follow-up began, all participants were offered a lifestyle session every 3 months. The DPP lifestyle group participants were also offered 4 group sessions per year. Those in the metformin group continued to receive metformin (850 mg twice daily). As in the DPP, the primary outcome was development of diabetes. Median follow-up from original DPP randomization was 10 years.

In the original DPP, diabetes incidence was reduced by 58% with intensive lifestyle and by 31% with metformin compared with placebo. During the follow-up, the incidence was decreased by 34% in the lifestyle group and by 18% in the metformin group compared with placebo.

The main finding of this study -- that the prevention or delay of diabetes with lifestyle intervention or metformin can persist for at least 10 years -- is indeed good news. In fact, the incidence rate in the lifestyle group was remarkably stable.

It is also important to note that the metformin group experienced a lower incidence rate during the DPPOS than the DPP. This finding suggests that adding modest lifestyle change (even if poorly attended) to metformin may enhance the drug’s effect.

What remains to be seen is whether lifestyle or metformin intervention reduces the debilitating (and costly) microvascular and macrovascular complications associated with diabetes. Until that is known, there remains little doubt that patients who can make positive lifestyle changes should do so.