Uveitis in peripheral spondyloarthritis patients: an ancillary analysis of the ASAS-PerSpA study

Background: Acute anterior uveitis (AAU) is the most frequent extra-musculoskeletal manifestation in spondyloarhtritis (SpA). Previous data on AAU focused on axial disease; therefore, it is not well known whether the clinical characteristics of patients with AAU and recurrent AAU differ between patients with axial and peripheral SpA. Objective: Primary objective was to compare the clinical characteristics of patients with AAU from patients without AAU in axial and peripheral spondyloarthritis (SpA) patients. Secondary objectives were to describe the clinical features of patients with MU in the subset of patients with peripheral SpA (pSpA) and the clinical characteristics of patients with recurrent AAU in SpA patients. Design: This is an ancillary analysis of the ASAS-PerSpA study which included 3152 patients, 2719 patients with axSpA and 433 with pSpA according to rheumatologist judgement. Methods: Recurrent MU was defined as the presence of two or more episodes of AAU ever. Univariable and multivariable binary logistic regression analyses were conducted to identify factors associated with the presence of AAU ever and the presence of recurrent AAU. Results: Overall, 663 patients (21%) presented AAU. Of them, 444 (66.9%) presented recurrent episodes. In patients with SpA, HLA-B27 positivity is the most important factor linked to the presence of MU, odds ratio (OR) = 2.70 (95% CI = 2.04-3.6). In patients with pSpA, HLA-B27 positivity was also the most relevant factor linked to the presence of AAU, OR = 6.08 (95% CI = 2.72-15.68). Moreover, disease duration, younger age and higher body mass index (BMI) were the only factors slightly linked to the presence of recurrent episodes, OR = 1.03 (95% CI = 1.01-1.04), OR = 1.01 (95% CI = 1.00-1.03) and OR =1.04 (95% CI = 1.01-1.08), respectively. Conclusion: HLA-B27 positivity is the most relevant factor linked to MU risk in SpA patients, and this association is even stronger in those patients with pSpA. Moreover, our study did not find an association between HLA-B27 positivity and recurrent AAU in SpA patients.