Objective: The U.S. National Diabetes Prevention Program (NDPP) is an intensive lifestyle intervention to prevent type 2 diabetes, but its real-world effectiveness is unclear. We estimated NDPP's effectiveness to prevent diabetes among insured, high-risk adults.
Research design and methods: This comparative cohort study included privately insured adults enrolled in 5,714 health plans spanning all 50 states who had medical claims between 2015 and 2019 indicating diagnosed prediabetes, followed by at least one procedure code indicating engagement in some form of lifestyle treatment. Each patient was classified as NDPP treated (at least one NDPP claim) or NDPP untreated (at least one claim for lower intensity services only). In the same quarter when each patient became eligible, we calculated the proportion of others in the same health plan who participated in NDPP. We used this variable, reflecting the intensity of external encouragement to start NDPP, as an instrumental variable (IV) to estimate differences in diabetes progression after NDPP treatment, while adjusting for individual risk factors.
Results: Among 3.73 million adults with diagnosed prediabetes, 245,896 had at least one claim for lifestyle treatment, of whom 27,703 (11.3%) were NDPP treated. NDPP-treated patients were more often women, aged <55 years, and less likely to live in low-poverty zip codes. With IV estimation, for every 100 adults participating in NDPP rather than in lower intensity services, there were 1.94 (95% CI 1.44-2.44) and 1.58 (95% CI 0.76-2.39) fewer cases of diabetes at 12 and 24 months, respectively.
Conclusions: For privately insured adults with prediabetes, using NDPP was associated with lower progression to diabetes over 1-2 years.
© 2026 by the American Diabetes Association.