Biologics are used to treat several inflammatory diseases, including RA, PsO, PsA, and AS; however, the cost of biologic therapies is high compared to non-biologic DMARDs. By using evidence-based assessment of comparative costs between biologics, healthcare resources can be properly allocated. This study used medical and pharmacy claims data to assess the utilitisation and cost of biologic treatment for RA, PsO, PsA, and AS. ETN (45%), ADA (32%), and INF (9%) were the most common medications and...