Pos0761 uveitis in oligoarticular juvenile idiopathic arthritis patients and in juvenile spondyloarthritis/enthesitisrelated arthritis – is there any difference?

Background Juvenile idiopathic arthritis (JIA) is the most common systemic disease causing uveitis in childhood and adolescence. JIA-associated uveitis has an estimated prevalence ranging from 11% to 30%, being higher in patients with oligoarticular JIA (oJIA), and to a lesser degree, in patients with juvenile spondyloarthritis/enthesitis related arthritis (jSpA-ERA), especially in HLA-B27 positive patients. Objectives To compare the demographic and laboratory characteristics and clinical outcomes of uveitis in oJIA and jSpA-ERA patients. Methods A retrospective single-center study of patients with oJIA and jSpA-ERA followed in a tertiary Hospital was conducted. ILAR classification criteria were fulfilled and sociodemographic, clinical and treatment data were collected from the Portuguese Rheumatic Diseases Register (Reuma.pt) and medical records. Age at onset of uveitis, disease duration, acute-phase reactant proteins at diagnosis, and characteristics of uveitis including complications, medical and surgical treatments were collected. Statistic was performed with independent samples t-test, Mann-Whitney U test, chi-square test and Fisher’s exact test. Statistical significance was set at a p-value <0.05. Results A total of 75 patients with oJIA (57 females, 76.0%) and 23 patients with jSpA-ERA (6 females, 26.1%) were included. Thirty-five of 98 patients (35.7%) developed uveitis, 28 patients had oJIA (80.0%) and 7 patients had jSpA-ERA (20.0). There were more females in the oJIA with uveitis group (p=0.006) and the age at diagnosis of JIA was lower in oJIA patients (p=0.005). ANA positivity was significantly higher in the oJIA with uveitis group (0.012) and HLA-B27 positivity was significantly higher in the jSpA-ERA with uveitis group (0.002). No significant differences were found in the ESR and CRP values at diagnosis and csDMARD/bDMARD use. Uveitis appeared in younger age in patients with oJIA than in patients with jSpA-ERA (8.4 ± 5.9 years vs 17.8 ± 7.2 years, p=0.001). In addition, the uveitis in the majority of oJIA patients was asymptomatic and the diagnosis was made during eye screening (n=21, 75.0%), as opposed to jSpA-ERA patients, in which the uveitis was symptomatic in the majority of patients (n=6, 85.7%, p=0.003). Concerning uveitis characteristics, anterior uveitis was the most frequent type in the 2 groups (and the only one in jSpA-ERA patients). In oJIA patients, panuveitis occurred in 8 patients (28.6%). However, no significant differences were found regarding the type of uveitis in the 2 groups. Patients with jSpA-ERA had more frequently unilateral alternating uveitis (n=4), followed by unilateral uveitis (same eye, n=3). No one developed bilateral uveitis. In oJIA patients, uveitis was more frequently unilateral (same eye, n=7), followed by bilateral involvement (n=9, 32.1%) and unilateral alternating (n=6, 21.4%). Complications were more frequent in oJIA group (n=15, 53.6%) than in jSpA-ERA (n=1, 14.3%, p=0.62). The most common complications in the oJIA group were cataracts (n=12, 42.9%), band keratopathy (n=8, 28.6%), ocular hypertension (n=8, 28.6%) and synechiae (n=6, 21.4%). Twelve patients (42.9%) with oJIA were submitted to eye surgery. On the contrary, no patient with jSpA-ERA was submitted to eye surgery. Conclusion In our study, uveitis manifested in 35.7% of the included patients with oJIA and jSpA-ERA. Uveitis in oJIA patients had poorer outcomes, such as complications and eye surgery requirement. Uveitis seems to have different characteristics depending on the JIA subtype, which leads us to think that possibly different immunologic mechanisms may be involved. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests None Declared.