The comparative efficacy of lifestyle intervention and metformin by educational attainment in the Diabetes Prevention Program

Objective. Educational attainment is inversely associated with type 2 diabetes risk, but it is unknown whether education impacts individuals' diabetes prevention efforts. We examined the comparative efficacy of intensive lifestyle intervention and metformin by educational attainment among participants in the Diabetes Prevention Program (DPP), an ongoing U.S. multi-site trial beginning in 1996. Methods. We studied 2,910 DPP participants randomized to receive lifestyle intervention, metformin, or placebo. Stratifying by educational attainment, diabetes incidence and relative risk reductions by treatment assignment were estimated using Cox proportional hazards regression. Results. 47% of participants had completed college and 53% had not. Compared to placebo, lifestyle participants who had completed college demonstrated a 68% reduction in diabetes incidence (95% CI = 56, 77), whereas those with less education experienced a 47% risk reduction (95% CI = 29, 61). For metformin participants, college graduates experienced a 49% relative risk reduction (95% CI = 33, 62), compared to 23% (95% CI = 1, 41) among those with lower educational attainment. There was a statistically significant education-by-treatment interaction with incident diabetes (p = 0.03). Conclusions. Intensive lifestyle intervention and metformin have greater efficacy among highly educated individuals. Future efforts to deliver these treatments and study their dissemination may be more effective if tailored to individuals' educational background. (C) 2015 Elsevier Inc. All rights reserved.