WASHINGTON (April 28, 2025)--The U.S. Diabetes Prevention Program, or DPP, reported on April 28 the 21-year follow-up of this randomized clinical trial showing that the original intensive lifestyle intervention reduced the development of diabetes by 24% and metformin reduced diabetes development by 17%.
The DPP had previously shown that after the first 3 years of study, the intensive lifestyle, aimed at moderate weight loss and increased physical activity, and the medication metformin reduced the onset of type 2 diabetes by 58% and 31%, respectively, compared with a placebo medicine. All participants were adults at high risk of developing diabetes. The long-term follow-up of 3,195 DPP participants, reported in the medical journal The Lancet Diabetes & Endocrinology, highlights the long-term benefits of the interventions in preventing the development of diabetes. Compared with the original placebo group, the median time without diabetes was extended by 3.5 years in the lifestyle group and 2.5 years in the metformin group.
William C. Knowler, consultant to the George Washington University Biostatistics Center, served as the lead author of the paper along with researchers from the National Institutes of Health and 28 other institutions and clinical sites across the U.S.
The original DPP clinical trial started in 1996, when the participants were 51 years old, on average, and 45% identified as members of U.S. minority groups who are especially affected by type 2 diabetes. The long-term benefits of the two interventions extended across all of the racial-ethnic groups included in the study.
In summary, the large intervention effects seen in the first few years of the trial led to sustained reductions in diabetes development over 21 years, increasing the years without diabetes. Despite the challenges in maintaining long-term intensive lifestyle and medicine interventions, even short-term interventions have long-lasting benefits, the study shows.
The DPP/DPPOS site at GW Biostatistics Center coordinated the large multi-center nationwide study and managed and analyzed data from the other participating institutions and clinical sites. Marinella Temprosa led a team at the GW Biostatistics Center, which is based at the GW Milken Institute School of Public Health.
“DPP and its long-term follow-up study have benefited from the collective dedication of participants across all sites and continued to show that lifestyle and metformin are effective diabetes preventive strategies,” said Temprosa. “DPP and its long-term follow-up study have benefited from the loyal dedication of our volunteer participants.”
The Diabetes Prevention Program and its long-term follow-up were generously funded by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health, and other agencies. The longer-term follow-up of the study participants for the development of additional age-related conditions, including Alzheimer’s disease, has been funded primarily by the National Institute on Aging. The investigators are grateful to the NIH for their past support of this work.
The study, Long-term effects and effect heterogeneity of lifestyle and metformin interventions on type 2 diabetes incidence over 21 years in the US Diabetes Prevention Program randomised clinical trial, was published April 28 in The Lancet Diabetes & Endocrinology.