Trajectories of disease activity in patients with JIA in the Childhood Arthritis and Rheumatology Research Alliance Registry

Objective. To describe 2-year trajectories of the clinical Juvenile Arthritis Disease Activity Score, 10 joints (cJADAS10) and associated baseline characteristics in patients with JIA. Methods. JIA patients in the Childhood Arthritis and Rheumatology Research Alliance Registry enrolled within 3 months of diagnosis from 15 June 2015 to 6 December 2017 with at least two cJADAS10 scores and 24 months of follow-up were included. Latent growth curve models of cJADAS10 were analysed; a combination of Bayesian information criterion, posterior probabilities and clinical judgement was used to select model of best fit. Results. Five trajectories were identified among the 746 included patients: High, Rapidly Decreasing (HRD) (n=199, 26.7%); High, Slowly Decreasing (HSD) (n=154, 20.6%); High, Increasing (HI) (n=39, 5.2%); Moderate, Persistent (MP) (n=218, 29.2%); and Moderate, Decreasing (MD) (n=136, 18.2%). Most patients spent a significant portion of time at moderate to high disease activity levels. At baseline, HSD patients were more likely to be older, have a lower physician global assessment, normal inflammatory markers, longer time to first biologic, and have taken systemic steroids compared with HRD. Those with a HI trajectory were more likely to be ANA negative, have a longer time to first biologic, and less likely to be taking a conventional synthetic DMARD compared with HRD. MP patients were more likely to be older with lower household income, longer time to diagnosis, and markers of higher disease activity than those with a MD trajectory. Conclusions. Five trajectories of JIA disease activity, and associated baseline variables, were identified.