Impact of TNF inhibitor medication on working ability in axial spondyloarthritis: an observational national registry-based cohort study

Objective: The aim was to investigate the effect of TNF inhibitor (TNFi) initiation on working ability and health-care resource utilization among axial SpA patients in a real-life setting. Methods: Patients with a clinical diagnosis of non-radiographic (nr-axSpA) or radiographic axial SpA initiating their first TNFi were identified from the National Register for Antirheumatic and Biologic Treatment in Finland. Sickness absences, including sick leave and disability pension, in- and outpatient days and rehabilitation rates, 1 year before and after initiating the medication were retrieved from national registries. Factors affecting result variables were studied using multivariate regression analysis. Results: Overall, 787 patients were identified. Rates of work disability days per year were 55.6 the year before treatment onset and 55.2 the year after, with significant differences between patient subgroups. The rate of sick leave decreased after starting TNFi treatment. However, the rate of disability pension continued to rise. Patients with a diagnosis of nr-axSpA experienced a decrease in overall work disability and, especially, fewer sick leaves. No sex differences were detected. Conclusion: TNFi interrupts the increase in work disabled days evident during the year before its initiation. However, the overall work disability remains high. Treating patients earlier in the nr-axSpA phase, regardless of sex, appears important in maintaining the ability to work.