Background Inconsistencies of classification, barriers in transition of care and lack of integrated paediatric and adult registries, has contributed to incomplete understanding of adult impact of Juvenile Idiopathic Arthritis (JIA).
Objectives To determine which JIA patients registered in Rheumatic Diseases Portuguese Register (Reuma.pt) fulfill classification criteria of adult rheumatic diseases and evaluate their adult outcomes.
Methods Cross-sectional evaluation of patients with JIA registered in Reuma.pt that at the time of data analysis were>18 years (yr) old. Fulfilment of classification criteria of adult rheumatic diseases was verified for each patient. Outcome assessments included disease activity assessed by the clinical juvenile arthritis disease activity score (JADAS 27), Health Assessment Questionnaire (HAQ) and damage index (JADI) at the time of last visit. Current and previous therapy were also assessed.
Results 635 JIA adult patients were registered in Reuma.pt. For 123 patients there was no data registered in adulthood and they were excluded. Of the 512 patients eligible for this study, 60% were females, mean age 32.7±12.2 yr, mean age at disease onset 10.3±4.4 yr and mean disease duration 22.4±17.2 yr (85%>10 yr and 24%>30 yr). Distribution according to ILAR classification: systemic (SoJIA) 13%, polyarticular rheumatoid factor (RF) negative 17%, polyarticular RF positive 14%, persistent oligoarticular 17%, extended oligoarticular 15%, enthesitis related arthritis (ERA) 19% and psoriatic arthritis (PsA) 4%. 53% of the SoJIA patients fulfilled criteria for Adult Still's disease, 53% with persistent systemic features and 40% with polyarticular involvement. Polyarticular RF negative patients fulfilled criteria for rheumatoid arthritis (RA) in 66% of the cases and in 94% of the RF positive patients. The majority (74%) of the persistent oligoarticular patients couldn't be classified in any adult rheumatic disease and the same was verified for 50% of the oligoarticular extended. 28% of the oligoarticular extended patients fulfilled criteria for RA and 20% for ankylosing spondylitis (AS). ERA patients fulfilled criteria for AS in 41% of the cases and 30% for undifferentiated spondyloarthritis. All PsA patients maintained this classification. 65% of the patients had active disease (15% low, 27% moderate and 23% high disease activity). Mean JADI score was 9.5±14.2 and mean HAQ score was 0.49±0.63 with 68% of the patients having none or mild disability and 11% severe disability. 86% had received DMARDs to control their disease and 66% were still taking a non-biologic or biologic DMARD.
Conclusions Most JIA patients fulfilled classification criteria for adult rheumatic diseases, with the exception of oligoarticular subtypes that often persist as a different diagnostic entity in adulthood. Most patients maintain active disease and the use of DMARDs at long-term follow up.
Disclosure of Interest None declared