THU0383 GENDER DIFFERENCES IN NONRADIOGRAPHIC AXIAL SPONDYLOARTHRITIS: FROM CLINICAL CHARACTERISTICS TO EFFECTIVENESS OF TNF INHIBITORS

Abstract

Background:While a male predominance is found in radiographic axial spondyloarthritis (r-axSpA), an equal male to female distribution was repeatedly reported for the nonradiographic disease form (nr-axSpA). Some important differences in clinical manifestations and response to treatment with tumor necrosis factor inhibitors (TNFi) between the sexes have been delineated for r-axSpA. It remains unclear, whether comparable sex differences can be assumed for nr-axSpA. Indeed, existing data on gender differences in nr-axSpA is limited to subgroups and is particularly scarce regarding effectiveness of treatment.Objectives:To investigate sex differences with regard to demographics, clinical manifestations and response to TNFi in nr-axSpA after exclusion of patients with co-morbid fibromyalgia (FM).Methods:Response to a first TNFi was assessed in 85 women and 78 men with nr-axSpA and without concomitant FM in the Swiss Clinical Quality Management Cohort. The primary outcome was the proportion of patients achieving a 40% improvement in the Assessment of Spondyloarthritis international Society criteria (ASAS40) at 1 year. Additional response outcomes were evaluated as secondary outcomes. Patients having discontinued TNFi were considered nonresponders. Logistic regression analyses were adjusted for baseline differences (Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Maastricht ankylosing spondylitis enthesitis score (MASES), diagnostic delay, body mass index (BMI)).Results:Baseline characteristics of women and men are shown in Table 1. Significant differences were restricted to diagnostic delay, BASDAI, MASES and BMI. An ASAS40 response was achieved by 17% of women and 38% of men (OR 0.34, 95% CI 0.12; 0.93, p=0.02). A lower response rate in women was confirmed in the adjusted analysis (OR 0.19, 95% CI 0.05; 0.62, p=0.009) as well as for the other outcomes assessed (Table 2).Table 1.Baseline characteristics of women and men with nr-axSpA starting a first TNFi (after exclusion of patients with co-morbid FM).ParameterN163MenN = 78WomenN = 85pAge, years16335.6±10.839.1±11.40.10Age at onset, years16227.9±8.628.1±8.50.66Diagnostic delay, years1624.1±7.67.8±9.90.005HLA-B27 positive, %14975.768.00.36Prior MRI sacroiliitis, %15470.868.30.86BASDAI1485.3±2.06.3±1.60.003ASDAS1403.3±1.03.4±0.70.29Elevated CRP, %15442.538.30.62BASFI1483.6±2.43.8±2.50.54BASMI1411.2±1.11.4±1.20.42EQ-5D14154.8±22.855.8±18.30.79Peripheral arthritis,%15941.652.40.20Enthesitis, %15880.585.20.53MASES1572.3±2.53.9±3.30.002csDMARDs ever, %16334.642.40.34Taking NSAIDs, %15092.986.20.29Current smoking, %13928.322.80.55BMI16025.9±4.224.0±4.4<0.001Table 2.Response rates of women versus men after 1 year of treatment with a first TNFi.Unadjusted analysesAdjusted analysesOutcomeWomen%Men%OR95% CIPOR95% CIPASAS4017380.340.12; 0.930.020.190.05; 0.620.009BASDAI5023500.300.11; 0.770.0070.190.05; 0.580.005ASDAS improv. ≥1.128580.290.10; 0.780.0080.260.08; 0.750.02ASDAS <2.127490.390.15; 1.000.030.180.04; 0.650.01ASDAS improv. ≥24260.130.01; 0.680.0050.040.00; 0.270.003ASDAS <1.38290.230.05; 0.820.010.070.01; 0.390.005Conclusion:Despite only few sex differences in patient characteristics in nr-axSpA, response rates to TNFi are significantly lower in women than in men.Disclosure of Interests:Regula Neuenschwander: None declared, Monika Hebeisen: None declared, Raphael Micheroli: None declared, Kristina Buerki: None declared, Pascale Exer: None declared, Karin Niedermann Schneider: None declared, Michael Nissen Grant/research support from: Abbvie, Consultant of: Novartis, Lilly, Abbvie, Celgene and Pfizer, Speakers bureau: Novartis, Lilly, Abbvie, Celgene and Pfizer, Almut Scherer: None declared, Adrian Ciurea Consultant of: Consulting and/or speaking fees from AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Merck Sharp & Dohme, Novartis and Pfizer.