Dr. Horton has played a pioneering role in several clinical trials that have looked at prevention of diabetes or diabetes complications with intensive lifestyle interventions or metformin, including the Diabetes Prevention Program (DPP), DPP Outcomes Study (DPPOS), and the Action for Health in Diabetes (LookAHEAD) Study. Some of the strongest evidence for lifestyle modification in the prevention of diabetes comes from the DPP program, which was established by the Centers for Disease Control and Prevention (CDC) to bring evidence-based lifestyle change programs to Americans at high-risk for type 2 diabetes.13
“At first, the DPP really looked at interventions to decrease progression from impaired glucose tolerance to diabetes, but as the study progressed, we began to look at prevention of cardiovascular disease and all of the longterm complications associated with diabetes, like retinopathy, nephropathy, and neuropathy. In this program, nondiabetic patients with impaired glucose tolerance or elevated FPG were randomized to metformin, intensive lifestyle modification, or placebo control. We chose metformin because along with effectiveness it conferred selective advantages such as low cost, long term safety data, and fewer adverse events compared to other potential candidates at the time which had also been shown to prevent type 2 diabetes, including troglitazone, rosiglitazone, pioglitazone, voglibose, and insulin glargine14-18” – mentioned Dr. Horton, further adding: “intensive lifestyle involved reducing dietary fat and overall calorie intake, increasing physical activity to at least 150 minutes a week of moderate-intensity exercise similar to brisk walking and to achieve and maintain at least a 7 percent reduction in their body weight. As reported13, the study was highly successful; the lifestyle intervention reduced the incidence of diabetes by 58% and metformin reduced the incidence by 31% compared to placebo. Furthermore, the incidence of metabolic syndrome (MetS) was reduced by 41% in the lifestyle group and by 17% in the metformin group compared to placebo. Quite remarkably, in people diagnosed with MetS at baseline, 18% in the placebo group, 23% in the metformin group, and 38% of the lifestyle group no longer had the syndrome at 4-years.19 Because the results of the study were so dramatic, it was stopped ahead of schedule, and we gave everyone an intensive lifestyle program including those in the original placebo and metformin groups. We asked the individuals to continue taking metformin in addition to lifestyle modification, which is what is known as the DPPOS, the long-term follow-up of the DPP study, which is still ongoing.”
