Evolving Economic Burden of Spondyloarthritis (2015-2023): A Nationwide Analysis of Direct and Indirect Costs.

OBJECTIVE: To assess temporal changes in the direct and indirect economic burden of spondyloarthritis (SpA), including psoriatic arthritis (PsA), in France between 2015 and 2023 using nationwide healthcare data. METHODS: We conducted a retrospective population-based study using the French National Health Data System (SNDS). Patients with SpA/PsA were identified through validated administrative algorithms based on ICD-10 codes, long-term disease status, and hospitalization records. Direct medical costs included all reimbursed expenditures related to hospitalizations and outpatient care. Indirect costs were estimated using reimbursed daily allowances for sick leave and work-related injuries, disability benefits, and annuities. Costs were aggregated annually and changes analyzed over time. RESULTS: In 2023, 270,290 individuals with SpA/PsA were identified, accounting for euro1.19 billion in total reimbursed expenditures (euro4,418 per patient). Outpatient care represented the largest share (66.1%), largely driven by medications (euro633.6 million), while hospital-based care accounted for 12.9%. Indirect costs reached euro250.6 million (21.0%). Between 2015 and 2023, the number of patients increased by 45.1%, and total expenditures rose by 52.2%. Medication costs showed the most pronounced growth (+60.7%), alongside a marked increase in outpatient care (+61.3%), reflecting a shift toward ambulatory management. In contrast, the relative contribution of hospital-based care declined, with a substantial decrease in high-cost inpatient drug expenditures. Indirect costs increased by 78.5%, despite stable proportions of beneficiaries receiving sick leave (16.4% to 16.8%) and disability benefits (9.6% to 10.6%), suggesting increased duration or severity of work impairment. CONCLUSION: Despite major therapeutic advances, the economic burden of SpA in France increased substantially between 2015 and 2023, driven by rising outpatient, medication-related, and indirect costs. These findings highlight the persistent societal impact of SpA and underscore the importance of integrating both healthcare utilization and work-related outcomes when informing healthcare policies and evaluating long-term disease burden.