Sex differences in the effectiveness of first-line tumor necrosis factor inhibitors in psoriatic arthritis; results from the EuroSpA Research Collaboration Network

Objective: Women with psoriatic arthritis (PsA) may have reduced tumor necrosis factor inhibitor (TNFi) effectiveness compared to men. We examined sex differences in treatment response and retention rates during 24 months of follow-up among patients with PsA initiating their first TNFi. Methods: Data from PsA patients across 13 EuroSpA registries starting their first TNFi were pooled. Logistic regression was used to analyze the association between sex and treatment response, using low disease activity (LDA) according to DAS28-CRP (<3.2) at 6 months as the primary outcome. Analyses were adjusted for age, country, csDMARD use, and TNFi start year. Retention rates were explored using the Kaplan-Meier estimators. Results: We analyzed the treatment response of 7,679 PsA patients (50% women) with available data on LDA at 6 months. At baseline, women and men had similar characteristics, including mean DAS28-CRP (women vs. men, 4.4 [SD 1.2] vs. 4.2 [1.2]), though patient-reported outcome measures were worse in women. At 6 months, 64% of women and 78% of men had LDA (relative risk, 0.82; 95% confidence interval, 0.80 to 0.84). This difference was similar after adjustment (0.83; 0.81 to 0.85). TNFi retention rates were evaluated in 17,842 PsA patients. Women had significantly lower retention rates than men at all time points (women: 79%/64%/50% at 6/12/24 months versus men: 88%/77%/64%). Conclusion: Despite comparable disease characteristics at baseline, women with PsA have reduced treatment response and retention rates to their first TNFi, highlighting the need to consider sex differences in PsA research and management.