Diabetes Prevention Program Outcomes Study

The Diabetes Prevention Program (DPP) was a multicenter trial examining the ability of an intensive lifestyle program or treatment with metformin to prevent or delay the development of type 2 diabetes in high risk individuals with prediabetes. The DPP study showed that both interventions reduced the incidence of diabetes in participants, compared with placebo; the lifestyle intervention proved more effective than metformin in preventing the onset of diabetes. The Diabetes Prevention Program Outcomes Study (DPPOS) is the long-term follow-up of the original DPP study. The DPPOS study sought to evaluate the effects of the interventions on the further development of diabetes and diabetes complications, including retinopathy, microangiopathy, and cardiovascular disease.

All active DPP participants were eligible for continued follow-up, and 88% of DPP participants enrolled in DPPOS (910 participants from the lifestyle, 924 from the metformin, and 932 from the original placebo groups). On the basis of the benefits from the intensive lifestyle intervention in the DPP, all three groups were offered group-implemented lifestyle intervention. Placebo was discontinued in the placebo group, metformin treatment was continued in the original metformin group, with participants unmasked to assignment, and the original lifestyle intervention group was offered additional lifestyle support. Comprehensive annual and semi-annual assessments similar to those done in the DPP study continued in DPPOS and included physical measurements, medical history updates, adverse event assessment, medication adherence and dispensing, questionnaires, and an annual oral glucose tolerance test (OGTT). OGTTs were discontinued after a confirmed diagnosis of diabetes.

The study found that prevention or delay of diabetes with lifestyle intervention or metformin can persist for at least 10 years; the cumulative incidence of diabetes remained lowest in the lifestyle group.

Data collected after the final DPP Bridge visits in 2002 through January 2014 are available from the Repository.