Project Summary/Abstract In an innovative scientific partnership between researchers, the UC Office of the President (UCOP), and Intermountain Healthcare, we will leverage existing electronic health record (EHR), insurance claims and DPP cohort data to examine the long-term effectiveness and cost-effectiveness of the Diabetes Prevention Program (DPP), as well as barriers and facilitators of participation in DPP in real-world settings. We proposed a rigorous evaluation using diverse data sources from the University of California (UC), which is a multi-campus university system and one of the largest employers in the State of California, and Intermountain Healthcare, which is a three-state regional health network. We will create a merged multi- ethnic and geographically diverse electronic cohort of adults at-risk of developing type 2 diabetes who enrolled in DPP and propensity-matched controls who did not enroll in DPP. We will include all DPP delivery models that have been in existence for nearly a decade in both systems. To assess the effectiveness of real-world DPP delivery, we will examine percent weight change at 5-years follow-up among adults at risk for developing type 2 diabetes, comparing those who completed DPP with those who did not enroll, and also comparing those who started but did not complete DPP with those who did not enroll (primary outcome). Secondary outcomes will examine changes in cardiovascular risk factors (e.g., blood pressure, tobacco use), rates of incident type 2 diabetes and diabetes-related healthcare service utilization and related costs. To assess the cost-effectiveness of real-world DPP delivery, we will estimate cost per case of type 2 diabetes prevented and cost per quality-adjusted life years (QALYs) gained at 5-years follow-up. We will also examine whether long-term effectiveness and cost-effectiveness vary by several factors, including DPP entry criteria (e.g., blood test vs. risk test), program delivery mode, social determinants of health, age group, or race and ethnicity. To examine barriers and facilitators to DPP participation, we will survey a representative subset of DPP participants and non-participants. We will leverage our team's expertise in DPP evaluation and track record of collaboration, and we will work closely with the coordinating center to carry out this comprehensive multi-site evaluation study. Findings from this study will inform future UC System and Intermountain Healthcare strategies addressing obesity and type 2 diabetes prevention, as well as dissemination of effective strategies to other large university systems, healthcare systems and employers.