Background Juvenile Spondyloarthropathy (jSpA) is SpA that starts during childhood and adolescence. Most children with jSpA fall into the categories of enthesitis-related arthritis (ERA), psoriatic arthritis, and undifferentiated arthritis of the ILAR classification of Juvenile idiopathic arthritis (JIA). Several disease activity scores have been developed for adults with SpA and for children with JIA (such as the Juvenile Arthritis Disease Activity Score or JADAS). However, neither of these measures has been validated in jSpA. The Juvenile Spondyloarthritis Disease Activity Index (JSpADA) has been recently developed and retrospectively validated in jSPA (1).
Objectives to assess disease activity in a cohort of patients with ERA on anti-TNF therapy using the JADAS-10 and the JSpADA.
Methods retrospective review of prospectively collected data. Patients with ERA treated with anti-TNF agents for ≥1 year and complete records were included. Information was collected on visits 0 (immediately prior to anti-TNF therapy start), 1 month after start of therapy, and every 3 months thereafter (up to 36 months) on demographics, therapeutic agents used, and disease activity measures: active joints (AJ), active enthesitis (AE), pain score, wellbeing according to the patient (VASp), disease activity according to the physician (VASphy), JADAS-10, JSpADA, and ESR. Comparisons between visits were performed using paired t-test; correlations between outcome measures was done using Spearman's correlation test.
Results 24 of 28 patients treated with anti-TNF agents fulfilled inclusion criteria. They were all male, 50% HLA-B27 positive; median age at entry 13 y, disease duration 4 y; median observation period was 21 months, 207 visits were recorded. Twenty-two (92%) children showed peripheral arthritis while 17 (71%) exhibited sacroiliitis on MRI/Xrays before starting therapy. Patients received etanercept (17, 2 were later switched to infliximab and adalimumab each), adalimumab (5), or infliximab (2). At baseline patients showed (medians): AJ 4.5, ESR 15 mm/h, VASphy 1, JSpADA 2, and JADAS 9.5. AE was present in 4 (17%) and lumbar limitation (LL) in 9 (37%) children. All patients showed JSpADA >0 and 95% children had JADAS >1. After 3 months JSpADA decreased to 1.25 and JADAS-10 to 6; 5 (21%) patients achieved inactive disease (ID, JADAS-10 ≤1). At visit 12 months: AJ 0 (p=0.0015), ESR 7 mm/h (p=0.06), VASphy 0.5 (p=0.005), JSpADA 1 (p=0.0004), and JADAS 1.75 (p=0.02); AE was present in 0 patients and LL in 6 (25%). JADAS-10 ≤1 was observed in 18 (75%) patients and JSpADA ≤1 in 21 (87%) children during follow-up. At baseline and at visit 12 months JSpADA showed high correlations with JADAS-10 (r=0.97, 0.75) and AJ (r=0.73, 0.77); JADAS-10 also correlated with AJ (r=0.92, 0.83).
Conclusions in this retrospective cohort of ERA patients with peripheral and axial active involvement there was a marked and progressive reduction in disease activity after the initiation of anti-TNF therapy. Both JSpADA and JADAS-10 demonstrated to be sensitive, feasible and useful activity measures that could be used in clinical trials or a treat to target strategy for JSpA.
Weiss et al. Development and Retrospective Validation of the Juvenile Spondyloarthritis Disease Activity Index. Arthritis Care Res 2014;66:1775–1782.
Disclosure of Interest None declared