Baseline ultrasound examination as possible predictor of relapse in patients affected by juvenile idiopathic arthritis (JIA)

[Arnaldo Libman]

Clinical and epidemiological research

Extended report

Baseline ultrasound examination as possible predictor of relapse in patients affected by juvenile idiopathic arthritis (JIA)

Author affiliations

1.    ¹Department of Rheumatology, ASST Centro Traumatologico Ortopedico G Pini-CTO, Milan, Italy

2.    ²Department of Internal Medicine, ASST Mantova Ospedale C Poma, Mantua, Italy

3.    ³Immunorheumatology Research Laboratory, Istituto Auxologico Italiano, Milan, Italy

4.    ⁴Department of Rheumatology, Pediatric Rheumatology Unit, ASST Centro Traumatologico Ortopedico G Pini-CTO, Milan, Italy

5.    ⁵Rheumatology Unit, Azienda Ospedaliera Universitaria di Verona, Verona, Italy

6.    ⁶Department of Pediatric Rheumatology, Ospedale Meyer, Florence, Italy

7.    ⁷Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy

Abstract

Objectives To define the correlation between joint ultrasonography and clinical examination in patients with juvenile idiopathic arthritis (JIA) and to assess whether synovitis detected by ultrasonography in clinically inactive patients predicts arthritis flares.

Methods 88 consecutive patients with JIA—46 (52%) with persistent oligoarthritis, 15 (17%) with extended oligoarthritis, 15 (17%) with rheumatoid factor-negative polyarthritis and 12 (14%) with other forms of JIA, all clinically inactive for a minimum of 3 months—underwent ultrasound (US) assessment of 44 joints. Joints were scanned at study entry for synovial hyperplasia, joint effusion and power Doppler (PD) signal. Patients were followed clinically for 4 years.

Results US was abnormal in 20/88 (22.7%) patients and in 38/3872 (0.98%) joints. Extended oligoarthritis and rheumatoid factor-negative polyarthritis were more frequent in US-positive than in US-negative patients (35.0% vs 11.8% and 30.0% vs 13.2%, respectively; P=0.005). During 4 years of follow-up, 41/88 (46.6%) patients displayed a flare; 26/68 (38.2%) were US-negative and 15/20 (75%) were US-positive at baseline. Abnormality on US examination, after correction for therapy modification, significantly increased the risk of flare (OR=3.8, 95% CI 1.2 to 11.5). The combination of grey scale and PD abnormalities displayed a much higher predictive value of relapse (65%, 13/20) than grey scale alone (33%, 6/18).

Conclusions US abnormalities are a strong predictor of relapse at individual patient level. Irrespective of treatment, the risk of flare in US-positive versus US-negative patients was almost four times higher. In case of US abnormalities, patients should be carefully followed regardless of both the International League of Associations for Rheumatology and Wallace categories.