PROJECT SUMMARY/ABSTRACT Peripheral arterial disease (PAD), defined as narrowed blood vessels causing decreased blood flow to the extremities, is a common diagnosis, affecting nearly 1 in 5 Americans and costing more than $21 billion annually. Claudication (pain with walking) is the most common manifestation of PAD. The invasive treatment of PAD has risen rapidly despite a lack of evidence of the long-term effectiveness of these procedures. Without a full understanding of the long-term effectiveness of these treatments and the motivations of providers prescribing these treatments, decision-making remains unclear. Providing long-term data of the effectiveness of treatment strategies and why providers choose treatments will directly improve patient shared decision- making. The goal of this research proposal is to describe the long-term effectiveness of interventions for claudication and to explore the provider motivations for treatment decisions. The three aims of this proposal are: 1) Describe the long-term comparative effectiveness of interventions in the treatment of claudication, 2) Measure the heterogeneity of treatment effects of interventions for claudication, and 3) Identify the key motivators of physician practice by assessing provider perceptions of the effectiveness of medical therapy, open surgery and endovascular interventions. The first two aims will use novel clinically-rich data from the Veterans Health Administration to measure the comparative effectiveness of treatment strategies. The third aim will employ semi-structured interviews to explore provider perceptions of treatment effectiveness and motivations for treatment decisions. The proposed research and training will provide Dr. Osborne with the necessary skills to become a leader in comparative effectiveness research in cardiovascular disease and enhance shared decision-making. Dr. Osborne's career development will be fostered by the mentorship of a diverse interdisciplinary team. Training will include graduate level advanced didactic coursework in organizational management, behavior and theory, qualitative research methods and implementation science. He will acquire new skills in the preparation of manuscripts, and grantsmanship. This training will directly lead to his development into an independent investigator, aimed at improving the quality of care for patients with PAD. This career development award will provide the groundwork for further studies to develop strategies to decrease variation in care and improve the treatment of patients with PAD.