Determinants of Difficult‐to‐Manage and Treatment‐Refractory Axial Spondyloarthritis: A Cross‐Sectional Analysis within a Longitudinal Cohort

Objective To estimate the prevalence of difficult‐to‐manage (D2M) and treatment‐refractory (TR) axSpA and to identify factors associated with D2M/TR disease in a longitudinal cohort. Methods We performed a cross‐sectional analysis on data from the Schroeder Arthritis Institute Spondylitis Program cohort. Assessment of SpondyloArthritis International Society (ASAS) definitions for D2M and TR disease were applied to axSpA patients. Sociodemographic and disease‐related characteristics were compared between groups, and multivariable logistic regression was performed to estimate odds ratios (ORs) for factors associated with D2M. Results Among 536 patients, 49 (9.1%) met the ASAS D2M definition and 12 (2.2%) were classified as TR. Compared with non‐D2M patients, those with D2M exhibited higher disease activity, worse function and spinal mobility, and a higher prevalence of comorbidities, degenerative spine disease, and fibromyalgia. TR patients showed greater disease burden and were more often male, HLA‐B27‐positive, and had radiographic axSpA, but were less affected by non‐inflammatory pain contributors. In multivariable analysis, higher spinal pain scores (OR 1.48, 95% CI 1.29 to 1.70) and fibromyalgia (OR 3.09, 95% CI 1.33 to 7.15) were independently associated with D2M. Conclusion Approximately one in ten axSpA patients in this cohort fulfilled the ASAS D2M definition, with a smaller proportion classified as TR. D2M status was associated with higher spinal pain and fibromyalgia, whereas TR patients had active disease with less non‐inflammatory pain contributors. These findings support the clinical relevance of the D2M construct and highlight the need for a tailored management approach in clinical practice. image