Objectives
To investigate the association between individual and country-level socioeconomic (SE) factors and health outcomes across spondyloarthritis (SpA) phenotypes.
Methods
Patients with axial SpA, peripheral SpA or psoriatic arthritis (PsA) from the ASAS-perSpA study (23 countries) were included. The effect of individual (age, gender, education and marital status) and country-level (e.g. Gross Domestic Product [GDP]) SE factors on health outcomes (ASDAS ≥ 2.1, ASDAS, BASFI, fatigue and ASAS-HI) was assessed in mixed-effects models, adjusted for potential confounders. Interactions between SE factors and disease phenotype were tested. A mediation analysis was conducted to explore whether the impact of country-level SE factors on ASDAS was mediated through b/tsDMARD uptake.
Results
In total 4185 patients (61% males, mean age 45) were included (65% axSpA, 25% PsA, 10% pSpA). Female gender (β = 0.14 (95%CI 0.06–0.23)) lower educational level (0.35 (0.25–0.45)) and single marital status (0.09 (0.01–0.17)) were associated with higher ASDAS. Living in lower GDP countries was also associated with higher ASDAS (0.39 (0.16–0.63)) and 7% of this association was mediated by b/tsDMARD uptake. Higher BASFI was similarly associated with female gender, lower education and living alone, without effect of country-level SE factors. Female gender and lower educational level were associated with worse ASAS-HI, while more fatigue was associated with female gender and higher country-level SE factors (lower GDP, -0.46 (-0.89 to -0.04)). No differences across disease phenotype were found.
Conclusions
Our study shows country-driven variations in health outcomes in SpA, independently influenced by individual and country-level SE factors and without differences across disease phenotypes.