Clinical and Radiographic Factors Associated With Difficult-to-Manage Axial Spondyloarthritis: A Multicenter Study.

OBJECTIVE

To evaluate the clinical characteristics, disease burden, and treatment patterns of axial spondyloarthritis (axSpA) using the recently proposed Assessment of Spondyloarthritis International Society (ASAS) definition of difficult-to-manage axSpA (D2M-axSpA).

METHODS

A total of 383 patients with axSpA were enrolled. This multicenter cross-sectional study was conducted in three tertiary care centers, enrolling consecutive axSpA patients from outpatient clinics. Patients were classified as D2M-axSpA based on prior use of biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) and persistent disease activity based on the ASAS definition. Logistic regression analysis identified factors associated with D2M-axSpA.

RESULTS

Among patients, 11.2% met the D2M-axSpA criteria. The cohort was 58.7% male, with a mean age of 43.5 ± 10.5 years. Radiographic axSpA was present in 70.8%, and 69.2% of patients had received biological therapy. D2M-axSpA patients exhibited higher inflammatory markers (ESR, CRP), increased disease activity (BASDAI, ASDAS-CRP), and greater functional impairment (BASFI, ASQoL). Peripheral arthritis (p = 0.001), enthesitis (p = 0.031), smoking history (p = 0.037), and comorbidities (p = 0.020) were significantly more frequent in D2M-axSpA. Among D2M-axSpA patients, 22/383 (5.7%) fulfilled the treatment-refractory criteria. Radiographic findings revealed higher rates of sacroiliac ankylosis, lumbar syndesmophytes, symphysitis, and ischial enthesitis, as well as mSASSS scores. Logistic regression identified anterior uveitis (OR: 4.474, p = 0.007), peripheral arthritis (OR: 2.684, p = 0.021), and comorbidities (OR: 2.878, p = 0.013) as independently associated factors.

CONCLUSION

Findings highlight the clinical and radiographic burden of D2M-axSpA and emphasize the need for optimized treatment strategies, particularly in patients with comorbidities, a history of anterior uveitis or peripheral arthritis, and those with a smoking history.