To determine the characteristics of juvenile idiopathic arthritis (JIA) patients seen during the transition period in order to compare paediatric classification criteria with those for adults.
Patients with JIA according to the ILAR classification and who had a consultation at transition between 2010 and 2017 were included in a retrospective bi-centre (Lyon, Lausanne) study. JIA classification criteria were compared to ACR/EULAR 2010 criteria for rheumatoid arthritis (RA), Yamaguchi criteria for adult-onset Still's disease (AOSD), ASAS criteria for spondyloarthritis and CASPAR criteria for psoriatic arthritis.
One hundred and thirty patients were included: 13.9% with systemic JIA, 22.3% with polyarticular JIA, 22.3% with oligoarticular JIA, 34.6% with enthesitis-related arthritis (ERA) and 6.9% with psoriatic arthritis; 13.1% had suffered from uveitis; 14.5% of patients had erosions or carpitis, mainly those with psoriatic arthritis, polyarticular or systemic JIA; 37.5% of patients with ERA displayed radiological sacroiliitis. When comparing paediatric JIA criteria with adult classifications, we found that: 66.6% of patients with systemic JIA fulfilled the criteria for AOSD, 87.5% of rheumatoid factor-positive polyarticular JIA and 9.5% of rheumatoid factor-negative polyarticular JIA met the criteria for RA, and 34.5% of oligoarticular JIA fulfilled the criteria for spondyloarthritis. Finally, 77.7% of patients with ERA met the criteria for spondyloarthritis, and 100% of patients with psoriatic arthritis JIA met the criteria for psoriatic arthritis.
Oligoarticular JIA and rheumatoid factor-negative polyarticular JIA seem to be paediatric entities, whereas the other types of JIA tended to meet the respective adult classification criteria.