Background/Purpose: The Juvenile Arthritis Disease Activity Score (JADAS) and its clinical version excluding the acute phase reactant (cJADAS) were developed for measuring disease activity in children with juvenile idiopathic arthritis (JIA). Cutoffs for the state of remission, low disease activity (LDA), moderate disease activity (MDA) and high disease activity (HDA) are necessary to interpret the scores. Aiming to obtain cutoffs suitable for any clinical setting, new values were recently developed for JADAS10 and cJADAS10 in oligoarthritis and polyarthritis, based on a large multinational dataset (Consolaro A, et al. Arthritis Rheumatol. 2017;69s10). Aim of the study is to externally validate the new cutoffs for JADAS10 and cJADAS10 disease activity states.

Methods: Four JIA patients dataset were considered: 1) 4397 oligoarthritis and polyarthritis patients from the EPOCA study; 2) 148 oligoarthritis patients from the TRIMECA trial; 3) 172 polyarthritis patients from the Abatacept trial, 4) 113 patients first starting methotrexate from a monocentric retrospective cohort (Swart et al, Ann Rheum Dis. 2018;77:336-342). Face validity was assessed in dataset 1) by plotting the proportion of patients in remission and LDA against the values of the 6 parameters in the ACR JIA core set. Discriminative ability was assessed in datasets 2) and 3) by comparing the percentage of patients below the cutoff values in the different ACR pediatric categories of response. In dataset 1) we compared in each disease activity state, the level of pain (0-10 VAS), functional ability impairment, and number of restricted joints and the frequency of patients satisfied with disease outcome, starting a new medication for JIA, and having morning stiffness. Predictive ability was assessed in dataset 4) by calculating sensitivity and specificity of the cutoffs for remission and LDA after 3 months for treatment response after 12 months.

Results: Only most relevant results are described. JADAS10 and cJADAS10 cutoffs for remission allowed up to 1 active joint for polyarthritis and 0 for oligoarthritis. In dataset 2), 42% and 63% of patients achieving an ACRp70 response met the JADAS10 cutoffs for remission and LDA, respectively. In dataset 3), these percentages were 48% and 82%, respectively. In dataset 1), the median level of pain was 0, 1.5, 3, and 5.5 for polyarthritis patients in cJADAS10 remission, LDA, MDA, and HDA, respectively (Kruskal-Wallis p<0.001). The frequency of satisfaction with disease outcome was 94%, 76%, 56%, and 24% for oligoarthritis patients in cJADAS10 remission, LDA, MDA, and HDA, respectively (Chi2 test p <0.001). In dataset 4), 100% and 71% of patients with oligoarthritis classified as non-responders after 12 months had JADAS levels after 3 months above the cutoffs for remission and LDA, respectively. For polyarthritis, 90% and 80% of non-responders had JADAS levels after 3 months above the cutoffs for remission and LDA, respectively.

Conclusion: New JADAS cutoffs showed good face and content validity; achievement of remission and LDA defined by the cutoffs predicted the response to therapy. Cutoffs were developed and validated in a large multinational dataset and they are ready for use in clinical trials and routine practice.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/new-jadas10-and-cjadas10-based-cutoffs-for-juvenile-idiopathic-arthritis-disease-activity-states-validation-in-a-multinational-dataset-of-4830-patients/