Background/Purpose: Recent EULAR/PReS recommendations have acknowledged the lack of unique and consensual tool to quantify disease activity in Still’s disease (SD). The systemic Juvenile Arthritis Disease Activity Score 10 (sJADAS10) (1) is to date the most advanced SD activity outcome measure in terms of construct validity and sensitivity to change with operable threshold already validated in children but not in adults.The objective of our work was to validate sJADAS10 thresholds in adult patients with SD.

Methods: Post hoc analysis of the cohort of Still’s patients from one unique reference center. Adult patients fulfilling Yamaguchi’s or Fautrel’s classification criteria, and with available clinical and biological data to calculate sJADAS10 score were included in the study. Disease activity was elicited sJADAS calculation. As a gold standard, patients were categorized into 4 groups according to the 4 qualitative definitions of inactive disease (ID), minimal disease activity (MDA), moderate disease activity (MoDA) and high disease activity (HDA) proposed by Rosina et al. (2) (Table 1). The agreement between sJADAS values and disease activity categorization was tested by Cohen’s kappa coefficient, to evaluate in what extent sJADAS values in adult patients fits with ID/MDA/MoDA/HDA qualitative categories.

Results: A hundred and twenty-nine visits from 93 patients were included in the study. The visits made by the same patient in a different disease activity state were considered as referring to distinct patients. Most of the patients were women (n= 89) mean aged (SD) of 36 (13) years with a mean (range) disease duration of 6,2 (0-40) years. Median (IQR) sJADAS was 12.8 (4.1-26.2). Forty-two patients were in HDA, 31 MoDA, 29 in MDA and 27 in ID according to their sJADAS-based statuses, respectively, whereas 39 were in HDA, 32 in MoDA, 20 in MDA and 38 in ID according to the qualitative disease assessment, respectively (Figure 1). Overall accuracy of sJADAS was 0.77 (95% CI :0.68- 0.84), whereas kappa coefficient was 0.69. Agreement was higher for patients with high disease activity.

Conclusion: sJADAS thresholds are relevant and validated by our work in adult patients with SD. These results are in favor of the use of sJADAS in both children and adults with SD and could position it as a relevant composite measure for assessing disease activity in SD. References 1. Tibaldi J et al. Rheumatology (Oxford) 2020; 59(11): 3505–3514. 2. Rosina S et al. Arthritis Rheumatol. 2024 Sep;76(9):1446-1454.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/validation-of-systemic-juvenile-arthritis-disease-activity-score-10-sjadas-10-in-adult-patients-with-stills-disease/