The mediating role of pain and function in the association between stiffness and quality of life in patients with axial spondyloarthritis.

Objective: The relationship between stiffness and quality of life (QoL) remains unclear. We therefore aimed to examine the role of pain and function in linking stiffness and QoL in patients with axSpA.

Methods: We used cross-sectional data from a registry of axSpA patients in a tertiary referral centre to assess the links among stiffness, pain and function on QoL. Path analysis was used to analyse the associations between these domains, pursuing four hypotheses: H - More stiffness is associated with poor QoL; H - More pain and decreased function are associated with poor QoL; H - More stiffness is associated with more pain and decreased function; H - The linkage between stiffness and QoL is mediated by function and pain.

Results: Data from 221 patients (Mean age 38.5, 79.0% males and 83.1% Chinese) were analyzed. Our mediation model achieved good fit (χ (10) = 7.06, p = 0.719, CFI= 1.00 TLI = 1.00, RMSEA < 0.001). Results supported all 4 hypotheses (p < 0.001): More stiffness, more pain, decreased function were associated with poor QoL. Function was associated directly with QoL. Stiffness was associated with QoL through both pain and function.

Conclusion: Optimization of QoL in patients with stiffness in axSpA requires effective control of both function and pain. Physiotherapy, exercises and medications may improve the QoL in these patients.