[Comparison of the Disease Activity Score-28 and Juvenile Arthritis Disease Activity Score in the juvenile idiopathic arthritis].

Introduction: the assessment of the activity of rheumatoid arthritis and juvenile idiopathic arthritis is made by means of different tools, respectively DAS-28 and JADAS.

Objective: To compare DAS-28 and JADAS with scores of 71, 27 and 10 joint counts in juvenile idiopathic arthritis.

Method: A secondary analysis of a phase III placebo-controlled trial, testing safety and efficacy of abatacept was conducted in 8 patients with 178 assessment visits. Joint count scores for active and limited joints, physician's and parents' global assessment by 0-10cm Visual Analog Scale, and erythrocyte sedimentation rate normalized to 0-10 scale, in all visits. The comparison among the activity indices in different observations was made through Anova or adjusted gamma model. The paired observations between DAS-28 and JADAS 71, 27 and 10, respectively, were analyzed by linear regression.

Results: There were significant differences among individual measures, except for ESR, in the first four months of biological treatment, when five of the eight patients reached ACR-Pedi 30, with improvement. The indices of DAS-28, JADAS 71, 27 and 10 also showed significant difference during follow-up. Linear regression adjusted model between DAS-28 and JADAS resulted in mathematical formulas for conversion: [DAS-28=0.0709 (JADAS 71)+1.267] (R(2)=0.49); [DAS-28=0.084 (JADAS 27) +1.7404] (R(2)=0.47) and [DAS-28=0.1129 (JADAS-10) +1.5748] (R(2)=0.50).

Conclusion: The conversion of scores of DAS-28 and JADAS 71, 27 and 10 for this mathematical model would allow equivalent application of both in adolescents with arthritis.