Validating 10-joint juvenile arthritis disease activity score cut-offs for disease activity levels in non-systemic juvenile idiopathic arthritis.

Objectives: To validate cut-offs of the Juvenile Arthritis Disease Activity Score 10 (JADAS10) and clinical JADAS10 (cJADAS10) and to compare them with other patient cohorts. Methods: In a national multicentre study, cross-sectional data on recent visits of 337 non-systemic patients with juvenile idiopathic arthritis (JIA) were collected from nine paediatric outpatient units. The cut-offs were tested with receiver operating characteristic curve-based methods, and too high, too low and correct classification rates (CCRs) were calculated. Results: Our earlier presented JADAS10 cut-offs seemed feasible based on the CCRs, but the cut-off values between low disease activity (LDA) and moderate disease activity (MDA) were adjusted. When JADAS10 cut-offs for clinically inactive disease (CID) were increased to 1.5 for patients with oligoarticular disease and 2.7 for patients with polyarticular disease, as recently suggested in a large multinational register study, altogether 11 patients classified as CID by the cut-off had one active joint. We suggest JADAS10 cut-off values for oligoarticular/polyarticular disease to be in CID: 0.0-0.5/0.0-0.7, LDA: 0.6-3.8/0.8-5.1 and MDA: >3.8/5.1. Suitable cJADAS10 cut-offs are the same as JADAS10 cut-offs in oligoarticular disease. In polyarticular disease, cJADAS10 cut-offs are 0-0.7 for CID, 0.8-5.0 for LDA and >5.0 for MDA. Conclusion: International consensus on JADAS cut-off values is needed, and such a cut-off for CID should preferably exclude patients with active joints in the CID group.