Sex-based differences in bDMARD initiation and persistence in spondyloarthritis: a 17-year follow-up study from the REGISPON-3 registry.

Abstract

This study examines sex differences in the initiation and retention rate of biological DMARDs among patients with spondyloarthritis (SpA) over a 17-year follow-up period and identifies sex-specific predictors of these treatment outcomes. This longitudinal observational study analysed data from 411 patients (271 males, 140 females) enrolled between 2004 and 2007 in the Spanish REGISPONSER registry (baseline) and re-evaluated 17 years later (2021-2024) in the REGISPON-3 study. Inclusion required a rheumatologist-confirmed diagnosis of SpA and the availability of data at both time points. Baseline and follow-up data were used to compare the time to initiation of bDMARDs and treatment persistence on the first and second lines of bDMARDs between sexes. Kaplan-Meier survival curves, Cox proportional hazards models and negative binomial regressions were employed to assess sex-specific differences in treatment outcomes. No notable differences were found between males and females in the initiation time of bDMARDs, regardless of whether it was measured from the onset of symptoms or the time of diagnosis. However, males exhibited a longer median persistence on the first bDMARD (88 months vs 48 months, Log-Rank P =0.004) and the second bDMARD (260 months vs 133 months, Log-Rank P =0.0007) compared with females. Multivariable Cox models identified distinct predictors of bDMARD initiation, varying by sex. Adverse events were reported more frequently as reasons for discontinuation in females, although inefficacy remained the primary reason for both sexes. Although the timing for starting bDMARDs in SpA patients was comparable between sexes, women exhibited significantly shorter biological treatment persistence.