Disease activity and widespread pain are main contributors to patient-reported global health in axial spondyloarthritis: an analysis of 6064 patients

Global health (GH) and health-related quality of life are patient priorities in axial spondyloarthritis (axSpA). Our objective was to assess the relative importance of disease-related factors including disease activity, and patient-related factors including comorbidities, to explain GH in axSpA. Post hoc cross-sectional analyses of 4 sets (COMOSPA, PERSPA, COMEDSPA, and DESIR) of patients fulfilling ASAS criteria for axSpA. GH was assessed through the ASAS Health Index (ASAS-HI) or the EuroQoL-5D-3L (EQ-5D). Disease-related factors included disease activity (ASDAS, psoriasis, arthritis, enthesitis, and CRP), disease duration, diagnostic delay, bamboo spine, and treatment. Non-disease-related factors included sociodemographic characteristics, comorbidities and chronic widespread pain. Multivariable logistic and linear regressions and partial variances (R2) were applied to identify independent determinants of GH. In 6064 patients (range 284-2756 across datasets), mean age ranged 38.9-45.8 years, 51-68% were male. GH was generally moderate: median ASAS-HI ranged 5.0-7.0. GH was explained by ASDAS (range of odds ratios, OR, 2.60-4.48) and chronic widespread pain (range of OR 2.19-8.39); other determinants included comorbidities and sociodemographic characteristics. Only 47-57% of the total variance in GH could be explained by the models; disease activity (partial variance, 16-26%) and chronic widespread pain (partial variance 12-15%) were the key contributing variables. A wide range of disease and non-disease-related variables usually collected in studies could only explain 47-57% of the variability in GH. Among these, disease activity and chronic widespread pain were most relevant and of similar magnitude of importance. These findings will be helpful for shared decision-making.