Predictors of Disease Activity in Patients With Juvenile Idiopathic Arthritis at 12 and 24 Months After Diagnosis

Abstract

Objective Identification of characteristics associated with active disease in juvenile idiopathic arthritis (JIA) could inform early disease treatment strategies. This study evaluated characteristics associated with active disease at 12 and 24 months after JIA diagnosis in the era in which biologic disease‐modifying antirheumatic drugs (DMARDs) became available for JIA. Methods This single‐center retrospective study from 2004 through 2018 assessed characteristics associated with active nonsystemic categories of JIA at 12 and 24 months after diagnosis. Relative prevalence (RP) of disease activity was evaluated in relation to prespecified characteristics. Using RP, the effect of increasing biologic DMARD availability on these predictors was assessed at 12 months. Results A total of 1,151 patients with JIA were included. At 12 months, a 40% to 45% higher point prevalence of active disease was noted in older children (>5 years). Patients with active disease at 3 months had a greater prevalence of active disease at 12 months (RP 1.5, 95% confidence interval [CI] 1.2–1.8) and 24 months (RP 1.3, 95% CI 1–1.6). Compared to oligoarticular JIA, polyarticular RF‐negative, psoriatic, and enthesitis‐related JIA had a greater prevalence of active disease at 12 and 24 months. At 24 months, a greater prevalence of active disease was observed in children ≥10 years. RP of active disease was 25% lower in the late cohort (2013–2018) than in the earliest cohort (2004–2008; RP 0.75, 95% CI 0.62–0.92) when more biologic medications were available, but disease activity predictors were broadly similar over time. Conclusion Patients with JIA with active disease at 12 and 24 months were older at diagnosis, categorized as polyarticular RF‐negative, psoriatic, or enthesitis‐related JIA. Active disease at 3 months after diagnosis was associated with worse outcomes at 12 and 24 months.