Development and validation of a composite disease activity score for juvenile idiopathic arthritis

To develop and validate a composite disease activity score for juvenile idiopathic arthritis (JIA), the Juvenile Arthritis Disease Activity Score (JADAS).

The JADAS includes 4 measures: physician global assessment of disease activity, parent/patient global assessment of well-being, active joint count, and erythrocyte sedimentation rate. These variables are part of the American College of Rheumatology (ACR) Pediatric 30 (Pedi 30), Pedi 50, and Pedi 70 criteria for improvement. Validation analyses were conducted on >4,500 patients and included assessment of construct validity, discriminant validity, and responsiveness to change. Three versions of the JADAS were tested based on 71-joint (range 0-101), 27-joint (range 0-57), or 10-joint (range 0-40) counts. Statistical performances of the JADAS were compared with those of 2 rheumatoid arthritis composite scores, the Disease Activity Score in 28 joints (DAS28) and the Clinical Disease Activity Index (CDAI).