Validation of the proposed ILAR classification criteria for juvenile idiopathic arthritis. International League of Associations for Rheumatology.

OBJECTIVE: The new International League of Associations for Rheumatology (ILAR) classification criteria were proposed to facilitate communication among pediatric rheumatologists. Before they are applied in daily practice they should be clinically validated.
METHODS: We retrospectively applied the proposed criteria on our pediatric rheumatology patient population seen between June 1 and August 31, 1998.
RESULTS: We saw 67 patients with oligoarticular (oJRA), 6 with polyarticular/RF negative (pJRA), and 8 with systemic juvenile rheumatoid arthritis (sJRA), all classified according to American College of Rheumatology criteria, 5 with juvenile psoriatic arthritis (PsA) according to the Vancouver criteria, and 11 with juvenile spondyloarthritis (SP) according to the European Spondylarthropathy Study Group preliminary criteria. Of the 97 patients, 85 could be clearly classified according to the ILAR criteria. Twelve patients (12%) were classified as "other." Six patients could not be classified as "oligo" because of a family history of psoriasis, and did not fulfill the criteria for PsA either. All 6 "other" patients fulfilled criteria for 2 different categories.
CONCLUSION: With this ILAR proposed classification criteria 88% of patients could be classified. In patients classified as "other," the psoriatic trait caused the most difficulty in classification.