P169 Sex differences and the impact of fibromyalgia on patient-reported outcomes in psoriatic arthritis

Abstract Background/Aims Psoriatic arthritis (PsA) is a multifaceted chronic autoimmune disease that can affect patients in many ways. This post-hoc analysis of the AsseSSing Impact in pSoriatic Treatment (ASSIST) study investigates the contributions of sex and fibromyalgia to patient-reported disease impact, measured using the Psoriatic Arthritis Impact of Disease (PsAID) score. Methods The ASSIST study was a cross-sectional observational study of patients with PsA from 24 centres across the UK, France, Germany, Italy and Spain. Clinical assessments included tender joint count (TJC), swollen joint count (SJC), Leeds Enthesitis Index (LEI), and body surface area (BSA). Descriptive statistics and t-tests were used to compare clinical variables by sex and fibromyalgia status. Multivariable linear regression models were constructed to assess the independent effects of sex and fibromyalgia (binary and continuous WPI/SSS scores) on PsAID, adjusting for age and clinical disease activity measures (TJC, SJC, LEI, BSA). A linear mixed-effects model with site as a random intercept was used to account for clustering. An interaction term was included to test whether the effect of fibromyalgia differed by sex. To assess whether consultation satisfaction differed by sex or fibromyalgia status, we compared mean CollaboRATE scores using independent-samples t-tests. Results A total of 503 patients were included (n = 256 male, n = 247 female). Women had significantly higher PsAID scores than men (mean 4.20 vs 2.78; p 0.001). Fibromyalgia was more prevalent among women and was associated with a 2.47-point higher PsAID score, after adjusting for clinical disease activity, sex and age. In models adjusted for fibromyalgia, the effect of sex on PsAID remained significant but was attenuated (β reduced from 1.01 to 0.65). When fibromyalgia symptom burden was modelled using WPI and SSS components, the sex effect was further reduced and no longer statistically significant (β = 0.26, p = 0.078). A significant interaction was observed between sex and fibromyalgia (p = 0.002), indicating that the impact of fibromyalgia on PsAID was greater in men than in women. CollaboRATE scores did not differ significantly by sex (mean difference: 0.10, 95% CI: -0.43 to 0.23, p = 0.55) or fibromyalgia status (mean difference: 0.02, 95% CI: -0.37 to 0.33, p = 0.91), indicating comparable levels of consultation satisfaction across groups. Conclusion Both sex and fibromyalgia contribute to perceived disease impact in PsA, but their effects are only partially overlapping. Fibromyalgia explains a substantial portion of the observed sex differences in PsAID, particularly when detailed symptom burden is considered. Notably, fibromyalgia appears to have a disproportionately stronger effect on PsAID scores in men, highlighting the need to consider sex-specific impacts of comorbid conditions in PsA management. Overall, consultation satisfaction was high and did not vary by fibromyalgia status or sex. Disclosure S.A. Gunawardana: None. M. Brooke: None. U. Kiltz: Consultancies; AbbVie, Amgen, Biocad, Biogen, Chugai, Eli Lilly, Fresenius, Gilead, Grünenthal, GlaxoSmithKline, Hexal, Janssen, MSD, Novartis, onkowoessen.de, Pfizer, Roche, UCB and Viatris.. Grants/research support; AbbVie, Amgen, Biocad, Biogen, Chugai, Eli Lilly, Fresenius, Gilead, Grünenthal, GlaxoSmithKline, Hexal, Janssen, MSD, Novartis, onkowoessen.de, Pfizer, Roche, UCB and Viatris. E. Lubrano: Consultancies; AbbVie, Eli Lilly, Janssen, MSD, Novartis and UCB. R. Queiro: Consultancies; Amgen, Eli Lilly, Janssen, MSD, Novartis, Pfizer and UCB. L. Gossec: Consultancies; AbbVie, Amgen, Bristol-Myers Squibb, Celltrion, Galapagos, Janssen, Eli Lilly, MSD, Novartis, Pfizer, Sandoz and UCB.. Grants/research support; AbbVie, Biogen, Eli Lilly, Novartis, Sandoz and UCB. L.C. Coates: Consultancies; AbbVie, Amgen, Bristol-Myers Squibb, Celgene, Eli Lilly, Gilead, Galapagos, Janssen, Moonlake, Novartis, Pfizer and UCB. Grants/research support; AbbVie, Amgen, Celgene, Eli Lilly, Janssen, Novartis, Pfizer and UCB;. Other; received speaker fees from AbbVie, Amgen, Biogen, Celgene, Eli Lilly, Galapagos, Gilead, GlaxoSmithKline, Janssen, Medac, Novartis, Pfizer and UCB..