BackgroundEvaluating the efficacy and refractoriness to treatment and determining factors associated with adverse outcomes in uveitis associated with spondylarthritis (SpA) are complicated by the lack of validated outcome measures.ObjectivesThe aims of this study were to develop an outcome score SpA-U in patients with uveitis associated with SpA and to determine factors associated with adverse outcomes in patients with uveitis under systemic treatment.MethodsThe outcome score SpA-U was defined by best-corrected visual acuity, anterior chamber inflammation, macular edema and inflammation of posterior chamber, global assessment, and refractoriness to treatment. Factors associated with adverse outcomes in uveitis were studied using linear regression. For categorical factors, marginal averages and their SEs are displayed together with linear regression coefficients with 95% confidence intervals. For continuous factors, averages and SDs are reported in addition to linear regression coefficients with 95% confidence interval. Two regression coefficients are reported for each variable: unadjusted and adjusted for age at diagnosis and sex.ResultsOne hundred ninety-seven uveitis outbreaks were included. Sixty-two uveitis outbreaks (31%) were classified as severe, 42 as moderate (21%), and 93 as mild (47%) based on the definition and construction of outcome score. The results of the linear regression model revealed that the uveitis activity was more severe in patients with smoking history (β = 0.34), axial and peripheral involvement (β = 0.43), Ankylosing Spondylitis Disease Activity Score >2.1 (β = 0.45), positive HLA-B27 (β = 0.29), female sex (β = 0.19), patients with C-reactive protein elevation (β = 0.002), and bilateral ocular involvement (β = 0.32). At the same time, shorter disease evolution (β = −0.02) was associated with less severe uveitis activity.ConclusionWe have determined factors associated with adverse outcomes in patients with uveitis associated with SpA by developing an outcome score SpA-U that integrates ocular inflammatory activity, visual acuity, global assessment, and refractoriness to treatment.