Background Uveitis is one of the most threatening complications in juvenile idiopathic arthritis (JIA). It occurs in approximately 10% of cases and may lead to severe vision loss. There is preliminary evidence from a retrospective study that early DMARD treatment can prevent uveitis.

Objectives To determine the frequency of incident uveitis in patients with JIA during the first years of disease and its influencing factors.

Methods Data source for this analysis was the National Paediatric Rheumatological Database (NPRD). Patients with early JIA (disease duration <12 months) were considered, if they were enrolled in the NPRD between the years 2002 and 2012, had no history of uveitis at inclusion and were prospectively followed for at least one year. Disease characteristics and details on treatment were provided by rheumatologists once a year along with patient-reported outcomes. The association of anti-inflammatory treatment with the occurrence of uveitis in follow-up was evaluated by discrete survival analysis.

Results 3,512 JIA patients fulfilled the inclusion criteria and were considered in the analysis. At first documentation in the NPRD, the patients had a median disease duration of 6 months and were treated with DMARDs in 35%, namely with methotrexate (MTX) in 29% and with biologics in 2%.

During the mean observation time of 3.3±2.3 years (range 2-11), 431 (12.3%) of the patients developed uveitis. In 251 cases (58.2%), first uveitis manifestation occurred after enrollment in the NPRD. These patients were younger at JIA onset (4.9 vs. 8.1 years), more often ANA positive (73.1% vs. 49.6%), and had more often oligoarthritis (63.4% vs. 51.6%) than those who never experienced uveitis during the observation period. Patients who received DMARDs experienced subsequently less frequently uveitis than those who weren't treated with DMARDs. In fact, patients on MTX (n=1,224) and biologics (n=308) treatment had a significantly reduced risk of uveitis (HR 0.73, p=0.017 and HR 0.50, p=0.006, respectively) compared to those who were not treated with MTX and biologicals in the year before uveitis diagnosis.

After the diagnosis of uveitis, patients were treated significantly more often with MTX (OR 3.7, p<0.001) or MTX and biologicals (OR=4.9, p<0.001) compared to patients without uveitis.

Conclusions This prospective population-based observational cohort study corroborates published data on a JIA-associated uveitis frequency of 12% in Central Europe. In addition to specific disease characteristics (e.g., disease onset after the age of 6, ANA negativity, and a disease category other than oligoarthritis), early treatment with DMARDs seems to be associated with a lower risk of uveitis in JIA patients.

Acknowledgements The study was supported by an unrestricted grant from Pfizer Pharma GmbH Germany (Forschungsförderung Rheumatologie). The national pediatric database is financially supported by the Children's Arthritis Foundation (Kinder-Rheumastiftung).

Disclosure of Interest C. Tappeiner Grant/research support from: Swiss Foundation for Grants in Biology and Medicine (SFGBM)/Swiss National Science Foundation (SNSF) and Novartis, J. Klotsche: None declared, S. Schenck: None declared, M. Niewerth: None declared, A. Heiligenhaus Grant/research support from: AbbVie, Pfizer, Novartis and Deutsche Forschungsgemeinschaft and has received study fees from AbbVie, Alimera Sciences, Allergan, Santen, and XOMA, K. Minden Grant/research support from: Pfizer and Abbvie, Speakers bureau: Pfizer, Abbvie, Roche/Chugai and Pharm-Allergan