Background In 1999 a registry of patients with juvenile idiopathic arthritis (JIA) and juvenile onset connective tissue diseases was established at Oslo University Hospital, Rikshospitalet.
Objectives To evaluate clinical characteristics in patients with JIA registered in the hospital based registry.
Methods The registry is based on written informed consent. JIA patients were classified using ICD-10 codes and data was registered at one time point. Gender, date of registration and year for disease onset was recorded, in addition to onset type, number of active joints and physician's global assessment of disease activity (VAS).
Results A total of 1069 JIA patients were registered. Mean age at inclusion was 9 years, mean age at disease onset was 6 years, and 65% were female. The distributions in various ICD-10 subgroups are shown in table 1. The most frequent subgroups were pauciarticular and polyarthritis (seronegative).
Physician's global was higher in girls (n=664) than in boys (n=353) in the group as whole; median 1.6 (IQR 0.4-3.3) versus median 1.3 (IQR 0.3-2.8); p=0.049. When comparing physician's global between JIA subgroups a difference was found between polyarthritis and pauciarticular arthritis, p=0,001. Patients with polyarthritis had higher physician's global than both pauciarticular and systemic; p=0,024. In 992 patients data on onset type was available. Of these 66% had pauci, 26% poly, 6% systemic and 2% unknown onset type. In 854 patients data on active joint count at time of registration was available. In the group as whole 42% had none, 24% one, 13% two, 6% three, 3% four and 12% five or more active joints.
Conclusions The age at onset and gender distribution is as expected. Girls had higher physician's global than boys and those with polyarthritis had higher physician's global than both systemic and pauciarticular arthritis. Ideally the register should have been based on the ILAR criteria instead of the ICD-10 codes. We consider the three subgroups pauci, poly and systemic to be the most consistent to the ILAR criteria. The registry is an important database for studies concerning outcome in JIA.
Disclosure of Interest None declared