Juvenile Psoriatic Arthritis Inception Cohort in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry: Characteristics and Early Disease Outcomes

Objective To characterize the demographics, disease characteristics, and treatment patterns of an inception cohort of children with juvenile psoriatic arthritis (JPsA) within the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry.

Methods Patients diagnosed with JPsA within 6 months of CARRA registry enrollment were included and observed for up to 24 months. Baseline disease characteristics, treatment history, disease activity measures, and patient-reported outcomes (PROs) were captured at 6-month intervals (± 3 months) at usual care visits during the 24-month period.

Results A total of 306 patients were included. Patients were predominantly female (62.4%), with a median age of onset of 11.0 (IQR 6.0-14.0) years. At CARRA registry enrollment, 52.3% had polyarticular-course JPsA, median active joint count was 3.0 (IQR 1.0-6.0), 20.1% had enthesitis, 34.3% had dactylitis, 9.5% had active sacroiliitis, and 58.8% had psoriasis. Tumor necrosis factor inhibitors were used in 61.1% of patients. In total, 20.5% of patients received treatment with ≥ 2 bDMARDs or traditional synthetic DMARDs. Clinical Juvenile Arthritis Disease Activity Score in 10 joints (cJADAS-10) improved from a median of 10.0 (IQR 5.5-15.0) at baseline to 1.0 (IQR 0.0-5.0) at 24 months. Improvements were also seen in active enthesitis and active sacroiliitis.

Conclusion In this inception cohort of JPsA in the CARRA registry, half of the patients had polyarticular presentation, and the majority required advanced therapy. Regardless of the treatment used, most patients had improvements in disease activity measures and PROs, with most achieving clinically inactive disease. However, escalation of treatment was common, highlighting the unmet need for precision medicine in identifying the optimal initial drug for each individual patient.