Background/Purpose: Prior ultrasound (US) studies in patients with juvenile idiopathic arthritis (JIA) in clinical remission have demonstrated the presence of subclinical synovitis. However, the significance of subclinical synovitis and positive power Doppler (PD) signal in these patients  is still not well understood. The objectives of this study were to evaluate possible factors associated with clinical flare over a 30-month evaluation in a group of patients with JIA in remission and assess if the presence of US features could predict disease flares.

Methods: In this two years longitudinal, single-center study we performed clinical, laboratory (every 6 months) and US evaluations (initial, after 12 and 24 months) in 35 JIA patients in clinical remission according to Wallace criteria (34 joints/60 articular recesses).  US parameters included synovial hypertrophy, PD signal and evidence of bone erosions. Subclinical synovitis was defined by the presence of synovial hypertrophy and/or positive PD signal. Flare was defined according to Wallace criteria.

Results: Of the 35 patients (80% female), 14 (40%) had persistent oligoarticular, 12 (34.3%) extended oligoarticular and 9 (25.7%) polyarticular JIA. Twenty patients (57.1%) were antinuclear antibodies (ANA) positive and none were rheumatoid factor (RF) positive. The mean age was 11.6 ± 3.8 years, the mean age of onset of JIA was 4.4 ± 3.2 years and the mean disease duration was 7.1 ± 3.5 years. Twenty-six (74.3%) patients were in remission on treatment and 9 (25.7%) were in remission off medication, for a median of 1.9 years. Twenty (57.1%) patients flared during the 30 months follow-up. Knees and ankles were most commonly affected. Eighteen (90%) were on treatment at the time of clinical flare. Of the 20 clinical flare patients, 7 (35%) had subclinical synovitis, 10 (50%) had synovial hypertrophy and 2 (10%) had positive PD signal at the time of flare. A Cox regression  analysis found that both a positive PD signal (p=0.046) and the use of medications (p <0.001) were significantly associated with flare, and the risk of flare in patients with a positive PD signal was five times greater than in patients without  a PD signal. Patients who were in remission on treatment showed a 14 times higher risk of clinical flare than patients off treatment.

Conclusion: The presence of subclinical synovitis detected by US in JIA patients in clinical remission did not predict flare of the disease. On the other hand, a positive PD signal showed a greater risk of JIA clinical flare. The remission on medication was also a risk factor for JIA flare. Patients in remission on treatment with a positive PD signal should be cautiously tapered due to the higher risk of clinical flares.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/positive-power-doppler-signal-increases-the-risk-of-clinical-flare-of-patients-with-juvenile-idiopathic-arthritis-in-clinical-remission-a-prospective-study/