gms | German Medical Science

Introduction: Musculoskeletal ultrasound (MSUS) evaluation is increasingly used in the monitoring of disease activity (DA) in patients with juvenile idiopathic arthritis (JIA). Few studies have evaluated MSUS scores for JIA, and without longitudinal data. The PROKIND prospective treat-to-target observational longitudinal multi-center study enrolled patients at diagnosis. We analysed the longitudinal change in MSUS scores and clinical DA (JADAS-10).

Methods: MSUS of standard (knee, ankle, midfoot (TN, CN)) plus other affected joints was performed at each visit. BM and PD were semi-quantitatively graded according to the paediatric OMERACT score. Synovial hypertrophy and effusion (BM) were graded from 0 to 3, depending on the extent of effusion and/or synovial hypertrophy and intra-synovial blood flow (PD) graded 0 (no intrasynovial Doppler signal) to 3 (confluent Doppler signals in more than 30% of the visible synovial tissue). For analysis, the highest BM and PD score of any affected joint per patient were added together as the Musculoskeletal Ultrasound Sum Score (MUSS, maximal score possible 6) and compared with clinical DA (JADAS-10 score), Figure 1 [Fig. 1].

Results: Patients with Oligoarthritis (OA), n=12, age (median, range) 4 (1–16) years, OA-Extended (OA-Ex)/RF- Polyarthritis, n=27, 6 (1–15) and RF+ Polyarthritis n=4, 13 (9–16) at baseline (Diagnosis, T0) were included. AT T0, 100% of patients with a polyarticular course had standard joint plus hip ultrasounds, and 81% of RF-/Oligo-Ex patients also had MSUS of their elbows and hands, in comparison to 100% of those with RF+ polyarthritis. At follow up the majority of patients received knee, ankle and midfoot scans as standard, and other joints were scanned according to clinical need. In each JIA-subgroup a significant reduction in JADAS-10 from T0 to T1 (3–4 mth vist) could be demonstrated, which correlated with >50% reduction in the MUSS. Both JADAS-10 and MUSS decreased in parallel at each visit until T4 (12–16 mths) after baseline.

Conclusion: This novel MUSS based on the sum of the highest BM and PD grade of each individual patient correlated well with DA over time after initial JIA diagnosis. In further studies MUSS could be tested and validated by higher numbers of patients in the treat-to-target management under therapy and remission.

Disclosures: Funding: ProKind is funded by the Innovation Fund “Gemeinsamer Bundesausschuss”, FKZ: 01VSF18031.