Identifying inadequate response among patients with ankylosing spondylitis and psoriatic arthritis prescribed advanced therapy in a real-world, commercially insured adult population in the USA.

Over 69% of patients with AS and 77% of patients with PsA had inadequate response to their index advanced therapy during 1 year after initiation. Health plan claims data appear useful to classify inadequate responders in AS and PsA. Key Points • Estimating inadequate response to advanced therapies and identifying factors associated with this outcome using claims data could improve treatment outcomes in AS and PsA. • In a sample of commercially insured US patients, over 69% of patients with AS and 77% of patients with PsA had inadequate response to their index advanced therapy during 1 year after initiation. Patient characteristics such as sex and prior therapy use were predictive of inadequate response to advanced therapies. • Health plan claims data appear useful to classify inadequate responders in AS and PsA and identify factors associated with this outcome.