An article published Online First and in a future edition of The Lancet reports that prevention or delay of type 2 diabetes with lifestyle intervention or metformin can persist for at least ten years. The article is the work of Dr. William C. Knowler of the U.S. National Institute of Diabetes and Digestive and Kidney Diseases and colleagues from the Diabetes Prevention Program Research Group.
The Diabetes Prevention Program (DPP) randomised clinical trial took place for 2.8 years. During this time, diabetes incidence in high-risk adults was reduced by 58 percent with intensive lifestyle intervention and by 31 percent with metformin, compared with placebo. The Diabetes Prevention Program Outcomes Study is a long-term follow-up study. The authors investigated the persistence of these lasting effects.
All active DPP participants were eligible for follow-up. Of the 3,150 participants, 2,766 (88 percent) were monitored: 910 from the lifestyle group, 924 from the metformin group, and 932 from the placebo group. On the basis of the benefits from the intensive lifestyle intervention in the DPP, all three groups were offered group-implemented lifestyle intervention. Metformin treatment was continued in the original metformin group (850 mg twice daily as tolerated). The original lifestyle intervention group was offered additional lifestyle support. The primary outcome was development of diabetes according to American Diabetes Association criteria.
During the 10-year follow-up since randomisation to DPP, results indicated that the original lifestyle group lost 7 kg of body weight, on average. Later they then partly regained to plateau at an average weight loss of 2 kg since randomisation. The modest weight loss with metformin was maintained. Diabetes incidence rates during the DPP were 4.8 cases per 100 people per year in the intensive lifestyle intervention group, 7.8 in the metformin group, and 11.0 in the placebo group. During follow-up, when all study participants were offered lifestyle intervention similar to the successful intervention in the DPP, diabetes incidence rates in the former placebo and metformin groups fell to rates similar to that of the original lifestyle intervention group, whose rate remained low during the entire study. Diabetes incidence rates during the follow-up study were 5.9 per 100 person-years for lifestyle, 4.9 for metformin, and 5.6 for placebo. Diabetes incidence in the ten years since DPP randomisation was reduced by 34 percent in the lifestyle group and 18 percent in the metformin group compared with placebo.
The authors explain: “In this study, onset of diabetes was delayed by about 4 years by lifestyle intervention and 2 years by metformin compared with placebo.”
They write in conclusion: “Our results have shown that a reduction in diabetes cumulative incidence by either lifestyle intervention or metformin therapy persists for at least 10 years. Further follow-up will provide crucial data for long-term clinical outcomes, including mortality… The long-term reductions in bodyweight and diabetes are encouraging, but further quantification of long-term outcomes is crucial to establish the benefits of diabetes prevention.”
In a supplementary comment, Dr Anoop Misra, Department of Diabetes and Metabolic Diseases, Fortis Hospitals, New Delhi, India, remarks: “Prevention of diabetes is a long and winding road. There seems to be no short cut, and a persistent and prolonged intensive lifestyle intervention seems to be the most effective mode to travel on it. However, more research needs to be done with dietary (eg, high-fibre, low-glycaemic-index foods), physical activity (aerobic plus resistance exercise), and pharmaceutical (especially glucagon-like peptide-based therapies) manipulations to prevent diabetes. We need more effective drugs for those who cannot follow intensive lifestyle therapy because of infirmity. Because of the high prevalence and rapid increase in the metabolic syndrome and diabetes, there is a need to apply these findings to, and generate data from, other ethnic groups and developing countries.”
“10-year follow-up of diabetes incidence and weight loss in the Diabetes Prevention Program Outcomes Study”
Diabetes Prevention Program Research Group
Written by Stephanie Brunner (B.A.)