gms | German Medical Science

Introduction: Musculoskeletal ultrasound (MSUS) determined disease activity (DA) is not yet a validated outcome measure in the treat-to-target management of juvenile idiopathic arthritis (JIA). We evaluate change in the MSUS Sum Score (MUSS) and JADAS10 in newly diagnosed patients with polyarticular JIA enrolled in the PROKIND prospective observational study.

Methods: MSUS images from patients with polyarticular subtypes of JIA were retrospectively analysed and scored according to the paediatric OMERACT group grading (range 0 to 3) for synovial hypertrophy and effusion (BM) and intrasynovial Doppler signals (PD). The highest BM and PD score of any affected joint/patient was combined to form the MUSS score (maximal possible score 6). MUSS <2 defined sonographic inactive disease (SID) and JADAS10<3.8 defined clinical inactive disease (CID).

Results: 19 patients with OA-Extended (n=1) and RF- Polyarthritis (n=18) were analysed. At T0, all patients had hip, knee, ankle and midfoot (TN, CN) ultrasounds. 81% also had elbow and wrist MSUS. At each follow up the majority of patients received knee, ankle and midfoot scans as standard, plus other joints according to clinical indication. Median (IQR) JADAS10 decreased from T0 (baseline, 24.4, 26.4), to T1 (3–4 months, 5.0, 10.5), T2 (2.5, 5.0), T3 (0.5, 2.0) and T4 (12–16 months, 0, 3.0). The MUSS score (mean, SD) also decreased in time: T0 (4, 1), T1 (1, 2), T2 (0, 2), T3 (0, 0) and T4 (1, 2). Patients with and without CID were analysed for the presence of SID (Table 1 [Tab. 1]). Almost all patients with CID also had SID. At T1, treatment escalation occurred in 4/4 of patients with active sonographic and active clinical disease, and 2/7 patients with active clinical but SID.

Conclusion: MUSS and JADAS10 correlated well when CID was reached. However, therapy was escalated more often in patients with both SID and CID than just CID. Therefore the combined use of SID and CID for the better discrimination of ongoing disease requiring step-up therapy requires further investigation. Prospective studies incorporating standardised MSUS investigation could test whether use of a combined USS+JADAS10 treatment target could improve short- and long-term outcomes.

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