OP0351 First diagnosis of uveitis is not higher among juvenile idiopathic arthritis (JIA) patients receiving etanercept compared to methotrexate

Background Uveitis is a common comorbidity among patients with juvenile idiopathic arthritis (JIA), occurring in approximately 1 in 10 JIA patients. Among other risk factors such as early ageat JIA onset, shorter disease duration and oligoarticular subtype, the use of etanercept (ETN) may also increase the risk of developing uveitis. However, previous studies have produced conflicting results, often limited by small sample sizes and limited follow-up time. Objectives To determine if patients receiving ETN have a higher risk of developing uveitis for the first time compared to patients receiving methotrexate (MTX). Methods The study population comprised JIA subjects recruited to the BSPAR ETN Cohort Study at point of starting ETN or MTX. Only patients with no prior history of uveitis were included. This was an on-drug analysis, whereby events were only included if the patient was on ETN or MTX at the time of uveitis onset. Follow-up began from date of first treatment to first uveitis diagnosis, discontinuation of ETN or MTX, most recent follow-up up to 30/11/16 or death, whichever came first. Crude incidence rates of uveitis per 100 person years (pyears) were calculated. Hazard ratios (HR) comparing risk of uveitis with ETN versus MTX were calculated using propensity adjusted Cox regression. Results Of 1517 patients, 1009 were registered to the ETN cohort (all receiving ETN) and 508 to the MTX cohort. ETN patients were older, with longer disease duration, and were less likely to have persistent oligoarthritis. The mean age at uveitis diagnosis was 8 years in the ETN cohort versus 5 years in the MTX cohort. The HR adjusted for age and gender, disease scores, disease duration, baseline steroid use, co-morbidity, ILAR subtype, and ethnicity found a lower risk of developing uveitis inpatients receiving ETN compared to MTX (0.30, 95% CI (0.10–0.90)) (table 1). Conclusions Within this cohort of UK children with JIA, a new diagnosis of uveitis is not more common among children receiving ETN compared to MTX, even after taking into account differences inage and disease duration between the cohorts. This is reassuring given there ports of possible increased risk of uveitis among children with JIA receiving ETN. Age appears to be a major influencing factor as patients in the MTX cohort were younger thus at a higher risk of uveitis. For patients with a high eruveitis risk other treatments options could have been selected, leading to possible confounding by indication, which in turn makes ETN look protective. Researchers should take these selection biases into account when analysing their results. Disclosure of Interest None declared