Can ultrasound-detected subclinical synovitis be an indicator of flare recurrence in juvenile idiopathic arthritis remission patients on tapered TNFi?

Objective Subclinical synovitis is often detected by musculoskeletal ultrasound (MSUS) in juvenile idiopathic arthritis (JIA) patients in clinical remission. The main objective of this prospective, observational, longitudinal, multicentre study was to evaluate the predictive value of MSUS-detected subclinical synovitis in relation to flares at 12 months following TNFi tapering in a JIA population in stable clinical remission. Methods We included 56 JIA patients in stable remission undergoing TNFi therapy tapered at baseline and in some cases at 6 months. We performed baseline and 6-month MSUS assessment on B-mode (BM) and power Doppler (PD) mode of 22 joints and 8 tendons. Results. Eighteen patients (32.1%) experienced a flare during the 12-month study period. BM synovitis was frequent (83.9%) but PD synovitis was scarcely found (8.9%). There were no significant differences in MSUS findings between patients who experienced a flare and those who remained in remission. Only 5 patients had positive for PD synovitis, in joints with BM synovitis grades 2 or 3, and none experienced a flare. Concomitant methotrexate (MTX) was more frequent in patients who were successfully tapered (71.1% vs. 27.8%; p=0.002) and patients older than 12 experienced a greater number of flares and earlier onset. Conclusion Subclinical synovitis, as detected by MSUS, proved not to be a predictor of flares. Those patients on a TNFi-tapered concomitant methotrexate regimen experienced the fewest flares although flare risk increased with age.