Correlation of ultrasonography synovitis with disease activity and clinical response to etanercept treatment in juvenile idiopathic arthritis patients

This study aimed to investigate the correlation of ultrasonography (US) of synovitis with disease activity and clinical response to etanercept (ETN) in juvenile idiopathic arthritis (JIA) patients. Eighty-two JIA patients who underwent ETN treatment for 24 weeks were consecutively enrolled. US evaluations of 28 joints (shoulder, elbow, wrist, metacarpophalangeal, and proximal interphalangeal of hands and knee) at baseline were performed using grey-scale US and power doppler (PD) US, and US synovitis was defined as grey-scale abnormalities or PD abnormalities. Clinical response was assessed according to the ACRpedi 50 response criteria. In total, 2296 joints were scanned and 608 (26.5%) joints presented US synovitis, which was numerically higher than clinical synovitis (513 (22.3%)). The mean number of joints showing synovitis on US was 7.42±3.35, which was also numerically higher than that of clinical synovitis (6.26±2.70). The number of joints showing synovitis on US was positively correlated with C-reactive protein, erythrocyte sedimentation rate, number of joints with active disease, number of joints with limited range of motion, physician's global assessment of disease activity, parent/patient global assessment of overall well-being, and childhood health assessment questionnaire score. Most interestingly, the baseline number of joints showing synovitis on US was increased in ACRpedi 50 response JIA patients compared to non-response JIA patients, and it serves as an independent predictive factor for higher clinical response to ETN treatment. In conclusion, US is a more sensitive test to evaluate subclinical synovitis and disease activity in JIA patients, and US synovitis might serve as a marker for predicting increased clinical response rate to ETN treatment.