Challenges of Assessment of SpondyloArthritis international Society Criteria in Real-World Colombian Patients With...

The Assessment of SpondyloArthritis international Society (ASAS) criteria classify spondyloarthritis (SpA) based on clinical presentation. Although widely applied, the measure's performance in Colombia's population remains unclear. This study aimed to characterize a Colombian SpA cohort, identify factors associated with peripheral SpA (pSpA), compare SpA subtypes, assess the performance of ASAS criteria, and compare the ASAS with modified New York (mNY) and European Spondyloarthropathy Study Group (ESSG) criteria.

This cross-sectional study included patients with newly diagnosed SpA by ≥ 1 expert rheumatologist. Participants completed a structured survey, physical examination, imaging, and laboratory tests. Researchers classified patients using ASAS, ESSG, and mNY criteria and compared clinical characteristics across groups. Finally, the performance of the ASAS criteria relative to the rheumatologist's diagnosis, mNY, and ESSG was analyzed.

The study analyzed 461 patients with SpA, of whom 58.1% had pSpA. Patients with axial SpA (axSpA) and pSpA differed significantly in age at onset, initial symptoms, buttock pain, Schober test, sacroiliitis, and HLA alleles. The ASAS criteria demonstrated a sensitivity of 90.8% when compared to rheumatologist diagnosis. Notably, 33.6% and 36.6% of patients classified as having radiographic axSpA (r-axSpA) by mNY or ESSG, respectively, were misclassified as pSpA under ASAS due to unmet entry criteria for axSpA.

This large Colombian SpA cohort, predominantly comprising patients with pSpA, revealed distinct clinical and imaging features between axSpA and pSpA. The ASAS criteria showed high sensitivity but failed to classify a subset of patients with radiographic sacroiliitis as having r-axSpA, highlighting limitations in its entry criteria for axSpA.