PROJECT SUMMARY Atrial fibrillation (AF) is the most common heart rhythm disorder and a leading cause of stroke in the elderly. Stroke related to AF is far more severe than stroke unrelated to AF. Oral anticoagulation (OAC) therapy is critical for stroke prevention and improved survival in AF. However, despite wide availability of OAC and accessible clinical guidelines and tools for identifying individuals with AF who stand to benefit from OAC, major gaps in the delivery of appropriate OAC therapy persist – leaving a large proportion of persons with AF at risk for stroke and its potentially devastating sequalae. The most reported types of gaps in delivery of OAC therapy include: (i) non- prescription, (ii) inappropriate medication, or (iii) sub-optimal dosing. Novel solutions are urgently needed to address the persistent gaps in the appropriate delivery of OAC therapy for persons with AF. Accumulating evidence suggests that pharmacist-based interventions for managing chronic diseases can be highly effective, sustained, with high potential for scalability and lead to greater adherence to guideline-directed targets and improved outcomes. The potential for efficacy around AF care is especially promising, as pharmacist-led warfarin anticoagulation clinics have been shown to improve therapeutic goals, patient satisfaction, and quality-of-life. Recent advances in OAC therapeutics now allow for effective drug choices that are safer and more easily administered than warfarin without the need for frequent monitoring. Thus, pharmacist-led interventions now represent an even more tractable approach to effectively closing gaps in OAC therapy delivery for stroke prevention in patients with AF. In this context, our first aim will identify potential pharmacist barriers to prescribing OAC at the patient, prescriber, pharmacist, and community levels and assess pharmacist knowledge regarding indications and type of OAC therapy in AF through administration of a survey instrument; second, we will evaluate in a cluster randomized clinical trial, the efficacy of a pharmacist-led intervention versus enhanced usual care on the delivery of guideline concordant OAC therapy for older individuals with untreated AF and high stroke risk presenting to community pharmacies. In secondary analyses, we will examine the effect of intervention on patient satisfaction, OAC shared decision-making, and on OAC adherence, health care utilization, and clinical events at 1 year. We will leverage our novel randomized trial population to also identify reasons for undertreated AF from a patient perspective and explore the impact of these factors on the efficacy of the intervention and OAC adherence. This proposed research will generate clinically actionable knowledge through an innovative and potentially sustainable stroke prevention strategy enacted by pharmacists at the point of medication delivery. Ultimately, these data may be used to shape policy regarding pharmacist-led management of ch...