Risk Factors and Biomarkers for the Occurrence of Uveitis in Juvenile Idiopathic Arthritis: Data From the Inception Cohort of Newly Diagnosed Patients With Juvenile Idiopathic Arthritis Study

OBJECTIVE: To analyze the prognostic value of demographic, clinical, and therapeutic factors and laboratory biomarkers and to assess their role in predicting uveitis occurrence in patients with juvenile idiopathic arthritis (JIA). METHODS: Patients with JIA were enrolled within the first year after JIA diagnosis. Demographic and clinical parameters were documented. Serum samples were collected at study enrollment, at 3‐month follow‐up visits within the first year, and then every 6 months. A multivariable Cox regression analysis was performed to evaluate the impact of demographic, clinical, laboratory, and therapeutic parameters on uveitis onset. RESULTS: We included 954 JIA patients (67.2% female, 54.2% antinuclear antibody [ANA] positive, mean ± SD age at onset 7.1 ± 4.6 years). Uveitis occurred in 133 patients (observation period 44.5 months). Young age at JIA onset and ANA positivity were significantly associated with the onset of uveitis (both P < 0.001). Treatment of arthritis with methotrexate alone (hazard ratio [HR] 0.18 [95% confidence interval (95% CI) 0.12–0.29], P < 0.001) or combined with etanercept (HR 0.10 [95% CI 0.04–0.23], P < 0.001) or adalimumab (HR 0.09 [95% CI 0.01–0.61], P = 0.014) reduced the risk of uveitis onset and the occurrence of uveitis‐related complications. Predictors of uveitis onset included elevated erythrocyte sedimentation rate at baseline (HR 2.36 [95% CI 1.38–4.02], P = 0.002) and continuing moderate or high disease activity during follow‐up as measured by the 10‐joint clinical Juvenile Arthritis Disease Activity Score (HR 4.30 [95% CI 2.51–7.37], P < 0.001). Additionally, S100A12 levels ≥250 ng/ml at baseline were significantly associated with the risk of uveitis (HR 2.10 [95% CI 1.15–3.85], P = 0.016). CONCLUSION: Apart from demographic risk factors and treatment modalities, JIA disease activity scores and laboratory biomarkers could be used to better define the group of JIA patients at high risk of uveitis onset.