LAUSR

Background Prognostic factors that may guide tapering decisions for DMARDs and TNFi on individual patient level are not available. To improve successful tapering subclinical synovitis may play a role in maintaining the remission state. Studies using ultrasound suggest that the presence of subclinical synovitis may elicit early disease relapse in remission. Objectives Our aim is to determine if ultrasound synovitis precedes disease relapse while tapering synthetic DMARD (sDMARD) or TNFi in patients with RA who achieved clinical remission on sDMARD and TNFi. Methods We included 125 RA patients (aged>17 years) treated with an sDMARD and a TNF-inhibitor who were in remission (DAS44≤2.4 & SJC≤1). Demographic characteristics, swollen and tender joints, laboratory variables and ultrasound synovitis (MCP2-5; PIP2-5; wrists; MTP2-5) were recorded at each visit (every three months) during one year follow-up. Patients were randomised to two tapering strategies: i) tapering sDMARD; ii) tapering TNFi. Disease relapse was defined as DAS44>2.4 or SJC>1. Ultrasound synovitis was defined as GS≤1 and/or PD≤0. To estimate whether ultrasound is able to identify patients who will have a disease relapse within three months follow-up a Cox proportional regression model for time to event data was used. Results: Ultrasound synovitis was found in 58% of RA patients in clinical remission. After one year follow-up 36% of RA patients had a disease relapse of whom 60% had ultrasound synovitis at baseline. table 1 shows the distribution of relapse en ultrasound synovitis for every three months. In the multivariate Cox model increasing number of joints with ultrasound synovitis was not significantly associated with disease relapse within three months follow-up (HR 1.21; 95%CI: 0.97-1.51) [table 2].Table 1 Distribution of disease relapse and US synovitis during follow-up, n (%) T0 T3 T6 T9 T12 US synovitis 72/125 (58) 60/124 (48) 62/112 (55) 40/96 (42) - Disease relapse 0 6/124 (5) 8/112 (7) 23/96 (24) 8/67 (12) US synovitis at previous visit - 4/6 (67) 5/8 (63) 14/23 (61) 6/8 (75) No disease relapse 0 118/124 (95) 104/112 (93) 73/93 (78) 59/67 (88) No US synovitis at previous visit - 46/118 (39) 47/104 (45) 23/73 (32) 29/59 (49) US = ultrasound Table 2 Multivariate Cox model with US synovitis or PD synovitis for disease relapse Model US synovitis HR (95% CI) Model PD synovitis HR (95% CI) Age 0.99 (0.97-1.02) 0.99 (0.97-1.02) Gender 1.08 (0.53-2.17) 1.05 (0.53-2.11) Time since diagnosis 1.02 (0.92-1.13) 1.03 (0.93-1.14) ACCP 0.47 (0.24-0.91) 0.51 (0.27-0.97) DAS (at time of US) 2.25 (1.21-4.19) 2.34 (1.25-4.41) US synovitis 1.21 (0.97-1.51) PD synovitis 1.35 (1.02-1.80) US = ultrasound; PD = power Doppler; HR = hazard ratio; ACCP=anti-cyclic citrullinated peptide antibody; DAS = disease activity score Conclusions Monitoring RA patients who started tapering their medication every three months showed limited value for ultrasound to identify patients who will have a disease relapse. Disclosure of Interest: None declared