Real-world sex differences in treatment persistence and reasons for discontinuation in psoriatic arthritis patients: results from the German RABBIT-SpA register

Background: In psoriatic arthritis (PsA), growing evidence indicates sex-specific differences regarding clinical manifestation and treatment outcomes. Research has highlighted that females may be less likely to achieve treatment targets and are more prone to discontinuing therapy, though data on sex-specific adverse events is limited. This analysis investigates sex differences in treatment outcomes, persistence, discontinuation reasons, and adverse events during first-line b/tsDMARD therapy. Methods: In this analysis bionaïve patients with PsA from the RABBIT-SpA register were included at the start of their first b/tsDMARD. Therapy persistence was estimated using the Cox-regression adjusted for age. Descriptive analyses were used to examine and compare sex–specific differences on reasons for therapy discontinuation. Results: A total of 457 female patients and 343 male patients were included. Females exhibited more severe joint involvement and poorer patient-reported parameters, such as higher disease activity, more pain, and greater functional limitations. In contrast, males showed more pronounced skin involvement and a higher prevalence of nail psoriasis. Females had lower treatment persistence rates, both in the overall analysis of all first-line b/tsDMARDs and in subgroup analyses restricted to TNFi and IL17i therapies. At 12 months, 52% of females and 68% of males remained on their initial b/tsDMARD therapy. Notable sex differences were also observed in the reasons for therapy discontinuation: males more frequently discontinued due to lack of efficacy or remission, while females more often stopped treatment due to adverse events. Our safety analysis indicated that although female patients experienced a greater number of overall adverse events, males reported serious adverse events at twice the rate. Conclusions: Our findings underscore the need for sex-specific treatment strategies and more comprehensive research into biological and sociocultural factors influencing therapy persistence and reasons for discontinuation in real-world settings. Tailored treatment strategies are needed with regard to biologic therapy to overcome worse therapeutic outcomes in female patients with PsA. Clinical trial number: Not applicable.