Real‐World Use of Biologic and Targeted Synthetic Disease‐Modifying Antirheumatic Drugs in Patients With Axial Spondyloarthritis in the United States: Persistence, Variables Associated With Persistence, and Dosing Variations

The objective of this study was to evaluate 12-month persistence of biologic and targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD) treatment in US patients with axial spondyloarthritis (axSpA) using real-world data, and patient baseline characteristics associated with increased or decreased persistence probability. Anonymized US claims from Merative MarketScan provided patient data relative to an index date (initiation of a new b/tsDMARD of interest for axSpA), from which patients were followed for 12 months or until b/tsDMARD non-persistence (≥ 90-day gap or b/tsDMARD switch) or MarketScan disenrollment. Persistence probabilities were estimated using Kaplan-Meier survival curves. Association of variables with persistence was estimated using multivariable Cox regression analyses. Of the 5970 adults with axSpA, 76.7% were prescribed a TNFi as their index b/tsDMARD, and 55.1% were b/tsDMARD-unexposed while 44.9% were b/tsDMARD-exposed before index b/tsDMARD. b/tsDMARD persistence probability was 67.8%, 57.7%, and 54.4% at 6, 9, and 12 months, respectively. 12-month persistence probabilities stratified by index b/tsDMARD mode of action or history of b/tsDMARD treatment ranged from 51.8% to 55.7%. Female sex and history of dactylitis were associated with decreased b/tsDMARD persistence, while history of inflammatory bowel disease, uveitis, and obesity were associated with increased persistence probability. Around half of patients studied were non-persistent with any given b/tsDMARD within a year of initiating therapy. Persistence was not considerably affected by index b/tsDMARD mode of action or history of b/tsDMARD treatment. Patient characteristics associated with decreased persistence probability, including female sex and dactylitis, may help clinicians recognize patients who may benefit from additional support to improve long-term treatment outcomes.