Giant cell arteritis (GCA) formerly known as temporal arteritis, is the most prevalent form of primary systemic vasculitis in adults, characterized by debilitating symptoms such as severe headaches, scalp tenderness, and jaw claudication. However, studies on GCA have been limited in volume or subject to retrospective meta-analysis. The United States Veterans Health Administration (VHA) holds the nation?s largest electronic medical database. Veterans comprise 7% of the American population, including 24% of the population over 75 years old2. Building upon a clinical study of one VHA site cohort3, we used this database to identify differences in demographics, risk factors, associated systemic conditions, and biopsy yield within the entire veteran population using novel methodology. The goal of this study is to identify differences in the criteria, risks, and outcomes of diagnosing giant cell arteritis in a veteran patient population compared to the general population.