OBJECTIVE: Several studies have suggested that patients with rheumatoid arthritis (RA) presenting with ultrasound (US) synovitis despite clinical remission have more subsequent flares than those who show both clinical and sonographic remission. The objective of our study was to investigate whether these results could be translated to a real-life setting.
METHODS: We compared the time from the first US performed in clinical remission to loss of remission (defined by a DAS28 > 2.6 or the need for stepping up treatment with disease-modifying antirheumatic drugs) within the Swiss Clinical Quality Management cohort of patients with RA, and we adjusted for relevant confounders. Analyses were repeated for different definitions of US-detected synovitis (US+) using greyscale, Doppler, and combined modes based on previously validated scores, and they were adjusted for relevant confounders.
RESULTS: There were 318 RA patients with 378 remission phases included. Loss of clinical remission was observed in 60% of remission phases. Residual US synovitis was associated with a shorter duration of clinical remission (median 2-5 mos) and a moderately increased hazard ratio (HR) for loss of remission (HR 1.2-1.5), with the highest HR for the combined US score. The association between US+ and loss of remission was strongest when the US measurement had taken place early in remission (shorter median duration of 6-20 mos) and when followup time was limited to the first 3 or 6 months (most HR between 2-4).
CONCLUSION: US-detected synovitis, particularly when US is performed early in clinical remission, has a moderate predictive power for loss of remission in a real-life setting.