Timing of uveitis onset in oligoarticular juvenile idiopathic arthritis (JIA) is the main predictor of severe course uveitis

Aim of the present study was to validate a statistical model to predict a severe course of anterior uveitis (AU) in patients with juvenile idiopathic arthritis (JIA). Methods:  Consecutive patients with newly diagnosed uveitis have been followed for at least 1 year with a standardized protocol. For each patient, demographic, clinical and laboratory characteristics, including time interval between arthritis and uveitis onset, α2-globulins level at arthritis onset, number of uveitis relapses/year, ocular complications and therapy and visual acuity, have reported. The validation procedure included the assessment of sensitivity, specificity and efficiency of previously published statistical model (Zulian et al. J Rheumatol 2002; 29: 2446–2453) in a new inception cohort of patients during a short length follow-up. Results:  Sixty patients with JIA, followed at 14 paediatric rheumatology–ophthalmology centres in Italy, entered the study. The mean age at arthritis onset was 4.4 years (range 1.2–15.8 years), and the mean interval time between arthritis and uveitis onset was 1.8 years (range: 0.0–14.2 years). After the first AU, patients, followed for a mean of 3.2 years, had a mean of 2.9 uveitis relapses. Twenty-two patients (36.7%) presented at least one complication. Using a probability cut-off value = 0.7, the statistical model revealed 80% sensitivity, 58% specificity and 65% efficiency. Conclusion:  The time interval between arthritis and uveitis onset resulted as the main predictor of severe course uveitis in JIA. The statistical model was able to predict the development of a severe course in 8 of 10 patients.