Background/Purpose: While, a Treat-to-Target strategy (T2T), treating patients with rheumatoid arthritis (RA) towards a certain target (eg. clinical remission; T2T-REM), is highly recommended, several patients in clinical remission often have residual synovitis on ultrasound-imaging (US). This may result in silent radiographic progression and clinical flare. It is arguable whether targeting US-synovitis may result in ‘deeper’ remission in clinical practice. We aimed to assess whether using US in a T2T strategy leads to more patients meeting clinical remission than using only clinical information.  

Methods: Patients with RA who started or changed csDMARD and/or anti-TNF treatment followed in centers with expertise in US and participating in BIODAM (2-year multicenter prospective observational cohort) were included. Clinical and US data [by the US7-score that includes 7 joints of the clinically dominant hand and foot for synovitis and tenosynovitis on gray-scale US (GSUS) and power-doppler US (PDUS) and erosions on GSUS] were collected every 3 months. Per visit and per protocol was decided whether the patient was treated according to the clinical definition of T2T with DAS44 remission as benchmark (T2T-DAS44). Though not mandatory, US-data could also be used for this purpose. T2T-DAS44 was considered correctly applied if: either i) a patient already had a disease activity score below the remission target (i.e. DAS44 remission) or ii) if not, treatment was intensified. A T2T strategy taking also US data into account (T2T-DAS44-US) was considered correctly applied if: either i) both DAS44 and US remission (all joints included in the US7-score with GSUS synovitis <2 and PDUS synovitis=0) were present; or ii) if not, the treatment was intensified. The main outcome was DAS44 remission. The effect of adding US to T2T (T2T-DAS44-US) on clinical remission 3 months later compared to a clinical remission benchmark only (T2T-DAS44) was analyzed using generalized estimating equations.

Results: In total 1,028 visits of 130 patients were included. T2T-DAS44-US was correctly followed in 41% of the visits, T2T-DAS44 in 23%, and any of these in 36%. Remission according to the DAS44 definition was achieved in 39% of the visits. Compared to the conventional T2T-DAS44 strategy, using a combined clinical and US benchmark for T2T led to a 40% lower – instead of higher – likelihood of DAS44 remission 3 months later [OR (95%CI): 0.59 (0.39; 0.91)(table).

Conclusion: Our results, from a non-randomized study, did not suggest an advantage of using US of 7 joints in addition to clinical examination as a T2T benchmark as compared to clinical examination alone in getting RA patients into clinical remission.