Validity of Remission Criteria in Rheumatoid Arthritis Compared to Ultrasound-Defined Remission

Objectives: Remission is the ultimate purpose of treatment in rheumatoid arthritis (RA). However, even when the most stringent composite scores are used, structural damages can occur; hence, ultrasonography (US) appears to be the best way to assess real remission. This study aimed to investigate the validity of different RA remission scores using US as a reference. Methods: An analytic diagnostic study, of 30 RA patients in remission (according to the Disease Activity Score in 28 Joints [DAS28]) and a control group with active RA, was conducted between January and October 2018 at Mongi Slim Hospital in Tunis, Tunisia. Among them, patients in remission were identified according to their Simple Disease Activity Index (SDAI), Clinical Disease Activity Index (CDAI) and the Boolean American College of Rheumatology/European League against Rheumatism activity index (ACR/EULAR) remission scores. The validity of each activity score for remission was calculated by considering the absence of power Doppler (PD) signals as a gold standard. Results: All patients were in remission according to the DAS28, with an average score of 2.03 (1.1–2.6). US examination showed PD signals in 57% of patients. A total of 26 patients were in remission according to the CDAI; a Doppler signal was detected in 58% of those cases. SDAI remission was accomplished in 19 patients, with PD activity in 53% of cases. Of the 14 patients in remission according to the Boolean ACR/EULAR criteria, synovial hyper-vascularisation was found in 64%. Considering true remission as the absence of PD signals, the most sensitive and specific score was the DAS28 (93% and 68%, respectively). Conclusion: Considering remission in RA as the absence of vascularised synovitis, the DAS28 is the most sensitive and most specific score.Keywords: Rheumatoid Arthritis; Ultrasonography; Doppler; Reproducibility of Results; Tunisia.