Nearly one in three adults in rural communities has prediabetes, a condition that increases the risk of heart attacks and stroke but can be managed by use of metformin, lifestyle interventions, and control of major cardiovascular (CV) risk factors. However, current prediabetes care is characterized by: (a) delayed recognition of prediabetes; (b) patient unawareness of effective treatment options for prediabetes; (c) poor control of concomitant major CV risk factors; (d) very low rates of metformin initiation; and (e) low rates of follow up to assess ongoing effectiveness of prediabetes management.1-3 Increased use of electronic health records (EHR) in rural communities now provides a new opportunity to improve awareness and management of prediabetes and to reduce these patients' significant CV risk burden. In this project, we implement and evaluate an EHR-linked, Web-based clinical decision support (CDS) system that identifies patients with prediabetes and provides patients and their primary care providers personalized, evidence-based CDS and follow up to reduce risk of heart attacks or stroke. To accomplish this objective, we randomly allocate 30 primary care clinics with their 450 primary care providers and estimated 17,000 prediabetes patients to one of two intervention arms: Usual Care; or else the prediabetes CDS to optimize management and follow up of prediabetes patients with uncontrolled CV risk factors. Random-effects models assess intervention impact on: (a) American College of Cardiology/American Heart Association (ACC/AHA) pooled CV risk; (b) major CV risk factors (blood pressure, lipids, HbA1c, smoking, and BMI); (c) use of evidence-based drugs, including metformin, and lifestyle interventions to manage prediabetes; and (d) patient and provider satisfaction with the intervention strategy. We also conduct a state-of-the-art cost and a cost-effectiveness analysis of the interventions relative to usual care. The Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework, supplemented by the Consolidated Framework for Implementation Research (CFIR), is used to assess implementation processes and outcomes in a rural/urban health system.