Evaluating the impact of the ASAS early axial spondyloarthritis definition on radiographic progression over 12 years

Abstract

Objective: This study aims to assess the impact of the ASAS early axial spondyloarthritis (axSpA) definition on radiographic progression, one important indicator of long-term disease burden, using the Modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) across a 12-year period, comparing early and established groups. Methods: Using data from the Korean spondyloarthropathy registry, this observational study retrospectively categorized patients into early or established axSpA groups based on the ASAS definition. Radiographic progression was assessed by analyzing annual changes in mSASSS. Two radiologists independently scored the radiographs. Statistical analyses, including linear regression, were employed to investigate the relationship between early axSpA group and radiographic progression, with adjustments made for pertinent covariates. Results: Analysis included intervals at 0–4, 0–6, 0–8, 0–10, and 0–12 years, involving 445 patients. No statistically significant differences were found in mSASSS changes between early and established axSpA groups, indicating similar progression rates regardless of TNF-α blocker inclusion. Univariable and multivariable analyses indicated no effect of early axSpA status on mSASSS changes. Conclusion: The findings suggest that the ASAS definition criteria for early stage do not significantly influence long-term radiographic outcomes in axSpA.