AbstractBackgroundSymptoms and comorbidities of ankylosing spondylitis (AS) considerably reduce health-related quality of life (HRQoL) and ability to work. This real-world study assessed rates of tumour necrosis factor inhibitor (TNFi) use and switching, treatment failure, and associations between failing TNFi and HRQoL, work productivity and activity impairment (WPAI).MethodsAS patients and their treating physicians completed questionnaires capturing patient demographics, clinical status, TNFi treatment history, reasons for switching TNFi, HRQoL and WPAI. Current TNFi was determined as “failing” if, after ≥3 months, physician-rated disease severity had worsened, remained severe, was “unstable/deteriorating”, physicians were dissatisfied with disease control and/or did not consider treatment a “success”.ResultsThe analysis included 2866 AS patients from 18 countries. Of 2795 patients with complete treatment data, 916 (32.8%) patients had never received TNFi therapy, 1623 (58.1%) patients were receiving their 1st TNFi and 200 (7.2%) patients had ever received ≥2 TNFi (treatment switch). Primary or secondary lack of efficacy were the commonest reasons for switching, and the mean delay in switching after primary lack of efficacy was 11.1 months. 232 (15.4%) patients on TNFi were currently “failing” who, compared to those with treatment success, reported poorer HRQoL: 5-dimension EuroQoL (EQ-5D-3 L): 0.63 vs. 0.78; Medical Outcomes Study Short-Form Health Survey version 2 (SF-36v2) mental component summary (MCS): 41.8 vs. 46.3; physical component summary (PCS): 40.2 vs. 45.1; impaired work productivity: 46.4% vs. 25.0%; and activity: 44.5% vs. 29.6%; allP < 0.001.ConclusionsAmong AS patients, switching TNFi is uncommon and delayed by nearly 1 year despite primary lack of efficacy. Patients currently failing TNFi experience worse physical function, HRQoL and work productivity.