Diabetes Prevention Program

The Diabetes Prevention Program (DPP) is a clinical trial that investigated whether modest weight loss through dietary changes and increased physical activity or treatment with the oral diabetes drug metformin (Glucophage) could prevent or delay the onset of type 2 diabetes in high risk individuals with prediabetes.

The study enrolled overweight persons with elevated fasting and post-load plasma glucose concentrations. Participants were randomized to placebo, metformin (850 mg twice daily), or a lifestyle-modification program with the goals of at least a 7 percent weight loss and at least 150 minutes of physical activity per week. The primary outcome measure was development of diabetes, diagnosed on the basis of an annual oral glucose-tolerance test or a semiannual fasting plasma glucose test, according to the 1997 criteria of the American Diabetes Association: a value for plasma glucose of 126 mg per deciliter (7.0 mmol per liter) or higher in the fasting state, or 200 mg per deciliter (11.1 mmol per liter) or higher two hours after a 75-g oral glucose load. Participation in DPP continued after a diagnosis of diabetes was made, although study medication was discontinued and participants were sent to their local primary care provider for treatment of diabetes once fasting glucose was > 140 mg/dl.

Results showed that both lifestyle changes and treatment with metformin reduced the incidence of diabetes in persons at high risk compared with placebo. Furthermore, the lifestyle intervention was more effective than metformin in preventing the onset of diabetes.

Supplemental measurements were collected using biospecimens that were obtained during the original DPP clinical trial. These measurements included antibodies, biomarkers, hormones, and vitamin D levels to assess the relationships between sex hormones, diabetes risk factors, and the progression to diabetes. The supplemental data showed that sex hormones were associated with diabetes risk in men, but these associations were not found in women. Furthermore, obesity and glycemia were more important predictors of diabetes risk than sex hormones.