Ultrasound remission in patients with rheumatoid arthritis in clinical remission

Objectives: The aim of the study was to assess ultrasound (US) remission in patients with rheumatoid arthritis (RA) in clinical remission using different definitions. Material and methods: This was a cross-sectional study including patients with RA in clinical remission defined by disease activity score (DAS28)-erythrocyte rate (ESR) <_ 2.6 for at least 6 months. Each patient underwent B-mode and power Doppler (PD) assessments of 42 joints and 20 tendons. B-mode and PD signal for synovitis and tenosynovitis (TS) were defined and graded semi-quantitatively (0-3) according to the outcome measures in rheumatology clinical trials (OMERACT). Several different definitions of US remission were examined: the absence of synovial hypertrophy (SH), TS on B-mode and PD signal, the absence of SH and PD signal, a grade <_ 1 of SH and the absence of PD, a grade <_ 1 of SH and PD, the absence of PD, or a grade of PD <_ 1. The DAS28, clinical disease activity index (CDAI), simple disease activity index (SDAI), and the Boolean American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) remission criteria were compared. Results: Thirty-seven patients were enrolled. The rate of remission according to the different composite indices was 70.2% for the SDAI, 64.8% for the CDAI, and 54% for the ACR/EULAR Boolean criteria. Synovial hypertrophy and TS in B-mode were detected in 94.6% and 40.5% of patients, respectively. Synovitis with PD signal was found in 59.5% and 13.5% of patients had TS with PD, respectively. Ultrasound remission at joints and tendons was found in 5.4-62.2% of patients. For the other remission criteria: CDAI, SDAI, and ACR/EULAR Boolean criteria, 7.7-60% of patients showed US remission at joints and tendons. Conclusions: Clinical remission, even classified by strict composite indices, does not seem to be the closest method to the concept of absence of inflammatory activity; hence the interest of integrating US in assessing remission in practice.