Sex Differences in Time to Initiate Nonsteroidal Anti‐Inflammatory Drugs or Biologic Disease‐Modifying Antirheumatic Drugs Among Patients With Axial Spondyloarthritis

We evaluated sex differences in time to initiation of receiving nonsteroidal anti‐inflammatory drugs (NSAIDs) or biologic disease‐modifying antirheumatic drugs (bDMARDs) among patients with axial spondyloarthritis (axSpA). Using the 2013 to 2018 IBM MarketScan Database, we identified 174,632 patients with axSpA aged ≥18 years. We evaluated the time between axSpA diagnosis and the first prescription NSAID dispensing (among those with no baseline NSAIDs reception) or bDMARDs infusion/procedure claim (among those who were dispensed two or more different prescription NSAIDs in the baseline period). Adjusted hazard ratios (aHRs) for time to initiation of patients receiving NSAIDs or bDMARDs were computed using survival analyses. Cox proportional hazard models estimated associations between sex and predictors of treatment initiation. Average age at diagnosis was 48.2 years, 65.7% were female, and 37.8% were dispensed one or more NSAIDs before axSpA diagnosis. Of those who did not receive two or more different prescription NSAIDs before diagnosis, NSAID reception was initiated earlier in female patients than in male patients (NSAID reception initiators: female patients (32.9%), male patients (29.3%); aHR 1.14, 95% confidence interval [CI] 1.11–1.16). Among those who received two or more different prescription NSAIDs in the baseline period, 4.2% received a bDMARD, whereas 77.9% continued receiving NSAIDs after diagnosis. Time to bDMARD reception initiation was longer for female patients than for male patients (aHR 0.61, 95% CI 0.52–0.72), but bDMARDs were received sooner among those who received NSAIDs in the baseline period. Prescription NSAID reception was more common than initiation of receiving bDMARDs among patients newly diagnosed with axSpA. Female patients appeared more likely to continue receiving NSAIDs after diagnosis, and the time to initiation of receiving bDMARDs was longer for female patients than for male patients.