Gender differences in clinical and prescribing characteristics of biologic and targeted synthetic drugs in naïve patients with rheumatoid arthritis: Data from BIOBADASER III registry

Rheumatoid arthritis (RA) is a chronic systemic inflammatory autoimmune disease that can lead to progressive joint damage and irreversible disability when inadequately treated. RA is more common in women than in men. Disease characteristics differ between genders in terms of comorbidities, extra-articular manifestations, quality of life, disease activity and functional scores. There is a possibility that RA may be managed differently depending on gender: under-treated due to professional bias when prescribing advanced therapies, or over-treated due to overestimation of disease activity. Our primary objective was therefore to examine gender differences in the time course from RA diagnosis to initiation of the first biologic disease-modifying antirheumatic drug (bDMARD) or targeted synthetic DMARD (tsDMARD) and to identify factors associated with earlier or later prescribing. We also aimed to assess the differences between men and women in clinical characteristics and disease activity at initiation of the first b/tsDMARD among bio-naïve RA patients. We analyzed RA patients from the BIOBADASER III registry who began their first b/tsDMARD between 2000 and 2023, stratified by treatment start year. Clinical characteristics were compared by sex, using linear regression models for DAS28. Kaplan–Meier curves and multivariate Cox regression identified factors influencing treatment initiation timelines. We included 3,384 patients (78.1% women). Males presented higher cardiovascular risk, females more osteoporosis and Sjögren Syndrome. At treatment start, females had lower mean age (54.8 vs. 57 years, p < 0.001) but longer disease duration (7.3 vs. 6.7 years, p = 0.031); higher DAS28-ESR, but not DAS28-CRP; higher subjective components of DAS28 and ESR but lower CRP and no differences in objective components. Disease duration differed between sexes only in the most recent cohort (≥ 2017, HR 0.9 (95% CI 0.81; 0.99), p = 0.026): female sex, age, and treatment with csDMARDs (other than methotrexate) were associated with later prescribing, whereas tobacco, obesity and treatment with methotrexate or glucocorticoids with earlier. Later prescribing in women despite higher activity rates merits reflection. Discrepancies between subjective and objective measures of DAS, and ESR and CRP, may reflect the need to establish different cut-off points for men and women, and opens a field of research worth exploring.