Journal of Medicine
C o py r ig ht © 2 0 0 2 by t he Ma s s ac h u s e t t s Me d ic a l S o c ie t y V O L UME 3 4 6
F E B R U A R Y 7, 2002
REDUCTION IN THE INCIDENCE OF TYPE 2 DIABETES WITH LIFESTYLE INTERVENTION OR METFORMIN
DIABETES PREVENTION PROGRAM RESEARCH GROUP*
Background Type 2 diabetes affects approximately 8 percent of adults inthe United States. Some risk factors — elevated plasma glucose concentrations in the fasting state and after an oral glucose load, overweight, and a sedentary lifestyle — are potentially reversible. We hypothesized that modifying these factors with a lifestyle-intervention program or the administration of metformin would prevent or delay the development of diabetes. Methods We randomly assigned 3234nondiabetic persons with elevated fasting and post-load plasma glucose concentrations 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 mean age of the participants was 51 years, and the mean body-mass index (the weight in kilograms divided by the square ofthe height in meters) was 34.0; 68 percent were women, and 45 percent were members of minority groups. Results The average follow-up was 2.8 years. The incidence of diabetes was 11.0, 7.8, and 4.8 cases per 100 person-years in the placebo, metformin, and lifestyle groups, respectively. The lifestyle intervention reduced the incidence by 58 percent (95 percent confidence interval, 48 to 66 percent)and metformin by 31 percent (95 percent confidence interval, 17 to 43 percent), as compared with placebo; the lifestyle intervention was significantly more effective than metformin. To prevent one case of diabetes during a period of three years, 6.9 persons would have to participate in the lifestyle-intervention program, and 13.9 would have to receive metformin. Conclusions Lifestyle changes andtreatment with metformin both reduced the incidence of diabetes in persons at high risk. The lifestyle intervention was more effective than metformin. (N Engl J Med 2002; 346:393-403.)
Copyright © 2002 Massachusetts Medical Society.
YPE 2 diabetes mellitus, formerly called non-insulin-dependent diabetes mellitus, is a serious, costly disease affecting approximately 8 percent of adults inthe United States.1 Treatment prevents some of its devastating complications 2,3 but does not usually restore normoglycemia or eliminate all the adverse consequences. The diagnosis is often delayed until complications are present.4 Since current methods of treating diabetes remain inadequate, prevention is preferable. The hypothesis that type 2 diabetes is preventable5,6 is supported byobservational studies and two clinical trials of diet, exercise, or both in persons at high risk for the disease7,8 but not by studies of drugs used to treat diabetes.5 The validity of generalizing the results of previous prevention studies is uncertain.9 Interventions that work in some societies may not work in others, because social, economic, and cultural forces influence diet and exercise. This is aspecial concern in the United States, where there is great regional and ethnic diversity in lifestyle patterns and where diabetes is especially frequent in certain racial and ethnic groups, including American Indians, Hispanics, African Americans, Asians, and Pacific Islanders.10 The Diabetes Prevention Program Research Group conducted a large, randomized clinical trial involving adults in the UnitedStates who were at high risk for the development of type 2 diabetes. The study was designed to answer the following primary questions: Does a lifestyle intervention or treatment with
The writing group (William C. Knowler, M.D., Dr.P.H., Elizabeth Barrett-Connor, M.D., Sarah E. Fowler, Ph.D., Richard F. Hamman, M.D., Dr.P.H., John M. Lachin, Sc.D., Elizabeth A. Walker, D.N.Sc., and David M....