Power Doppler ultrasound, but not low‐field magnetic resonance imaging, predicts relapse and radiographic disease progression in rheumatoid arthritis patients with low levels of disease activity

Abstract

Subclinical inflammation and radiographic progression have been described in rheumatoid arthritis (RA) patients whose disease is in remission or is showing a low level of activity. The aim of this study was to compare the ability of ultrasonography and magnetic resonance imaging (MRI) to predict relapse and radiographic progression in these patients. Patients with RA of short or intermediate duration that was either in remission or exhibiting low levels of activity according to the Disease Activity Score (DAS) were included in the study. Over a period of 1 year, patients underwent clinical and biologic assessments every 3 months and radiographic assessments at baseline and 12 months. Radiographs were graded according to the modified Sharp/van der Heijde score (SHS). At baseline, patients underwent ultrasonography and MRI, which were graded using binary and semiquantitative scoring systems. Relapse was defined as a DAS of ≥2.4, and radiographic progression was defined as an increase in the SHS of ≥1. We tested the association of values by multivariate logistic regression. A total of 85 RA patients with a mean disease duration of 35.3 months were studied. RA was in remission in 47 of these patients, and 38 had low levels of disease activity. At 1 year, 26 of the 85 patients (30.6%) showed disease relapse, and 9 of the 85 patients (10.6%) showed radiographic progression. The baseline PD synovitis count (i.e., the number of joints at baseline for which the power Doppler [PD] signal indicated synovitis) predicted relapse (adjusted odds ratio [OR] 6.3; 95% confidence interval [95% CI] 2.0-20.3), and the baseline PD synovitis grade predicted disease progression (adjusted OR 1.4 [95% CI 1.1-1.9]). MRI was not predictive of outcomes. For RA patients whose disease is in remission or who have low levels of disease activity, PD signals on ultrasonography could predict relapse or radiographic progression and identify those whose disease is adequately controlled, which is especially helpful when considering treatment tapering or interruption.