Background/Purpose: In the last decade, there have been major advances in the management of juvenile idiopathic arthritis (JIA), including the shift towards early aggressive interventions and the development of new therapeutic agents and combination treatment strategies. A reliable documentation of the advances in therapeutic effectiveness creates the need for validated and clinically useful criteria that describe precisely the clinical state of the patient. The study was aimed to determine cut-off values for the state of high disease activity (HDA) in JIA based on the Juvenile Arthritis Disease Activity Score (JADAS).

Methods: For the selection of cut-offs, data from a clinical database including 618 children with JIA followed between 2007 and 2011 were used. Patients were defined as being in HDA when one of the following  therapeutic interventions was prescribed: 1) start of methotrexate; 2) intraarticular corticosteroid therapy; 3) start of a biologic medication; 4) start of systemic corticosteroid therapy. Patients were defined as having low disease activity (LDA) when they were receiving no therapy or had therapy discontinued, tapered or left unchanged for > 1 year. For each patient, 1 visit in HDA and 1 visit in LDA were retained. Optimal JADAS cut-offs were determined by calculating the 25^thpercentile of cumulative score distribution in patients with HDA and by assessing their ability to discriminate between the states of HDA and LDA through ROC curve analysis (including calculation of Youden index and fixed 90% specificity). Cross-validation of cut-offs  was performed in 490 JIA patients enrolled in the PRINTO methotrexate trial (Ruperto et al, A&R 2004;50:2191-201) and on 358 patients followed longitudinally at study centers for a median of 1.7 years, and was based on assessment of discriminative and predictive validity.

Results: The cut-offs were calculated separately for patients with oligoarticular and polyarticular course of joint disease (irrespective of ILAR category) owing to the different severity of these 2 JIA phenotypes. Complete clinical data were available for 258 visits of patients with oligoarthritis and 289 visits of patients with polyarthritis. JADAS-10 and JADAS-71 cut-offs were 7.6 for oligoarthritis and 10.6 for polyarthritis. JADAS-27 cutoffs were 7.7 for oligoarthritis and 8.9 for polyarthritis. Validation analyses showed that at baseline visit of methotrexate trial 94.7% of patients had a JADAS higher than the proposed cut-off for JADAS. At 6-month visit, the percentage of patients with a JADAS higher than the cut-off was 85.6% among nonresponders and 23.8% among responders. Evidence of predictive ability of the cut-offs was obtained by demonstrating that in the longitudinal patient sample, the percentage of patients with inactive disease or with a C-HAQ score of 0 at final visit was significantly lower among patients who had a JADAS above the cut-off value at first visit than among those who did not.

Conclusion: We developed the JADAS cut-offs for HDA in JIA. The cut-offs revealed strong discriminative and predictive ability in a clinical trial and are, therefore, potentially applicable in clinical practice, observational investigations, and therapeutic studies.

---

« Back to 2012 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/development-of-cut-off-values-for-high-disease-activity-in-juvenile-idiopathic-arthritis-based-on-the-juvenile-arthritis-disease-activity-score/