Background The latest recommendations for the treatment of rheumatoid arthritis (RA) focus on the achievement of clinical remission. However, joints with subclinical positive power Doppler (PD) signals in ultrasonography (US) test might be exposed to the risk of destruction and there is a possibility that patients with PD positive synovitis even after the achievement of clinical remission should be treated more intensively.
Objectives The aim of this study was to assess subclinical synovitis by US and evaluate the effects of additional intensive treatment for preventing joint damage among RA patients in clinical remission.
Methods US examination was performed consecutively for 134 patients with RA in clinical remission defined as DAS (Disease activity score) 28<2.6. US assessment was underwent at 34 synovial sites in 30 joints: bilateral first to fifth metacarpophalangeal (MCP) joints (dorsal recess), first interphalangeal (IP) joint and second to fifth proximal-interphalangeal (PIP) joints (dorsal recess) joints, the wrists (dorsal radial, dorsal median and dorsal ulnar), and second to fifth metatarsophalangeal (MTP) joints (dorsal recess). The gray scale (GS) and PD signals were scored in each joint using a semi-quantitative scale from 0 to 3. According to the results of US assessment, the patients with PD positive synovitis (PD1 in at least one joint) were randomly assigned to two groups; the group to be treated by increasing the dose of MTX (MTX increasing group) or the group to continue their current treatment (MTX stable group) until week 52. The patients without active synovitis continued their current treatment (PD negative group). Standard radiographs of hands and forefeet were obtained at baseline, week 24 and 52. Radiological joint damage was assessed according to the modified total Sharp score (mTSS).
Results Of 134 patients with clinical remission, PD positive synovitis was found in 101 patients (75.4%) at baseline. After the randomization, 51 patients were assigned to MTX increasing group and 50 patients to MTX stable group. Thirty-seven patients in MTX increasing group (72.5%), 42 patients in MTX stable group (84%) and 20 patients in PD negative group (60.6%) completed this study until week 52. Total PD score was significantly decreased in MTX increasing group comparing to MTX stable group (-3.9 vs -2.0, p=0.019). The progression of mTSS was significantly suppressed in MTX increasing group compared to MTX stable group at both week 24 (0.27 and 1.02, p=0.007) and week 52 (1.03 and 2.02, p=0.038). Especially, the progression of mTSS in patients treated with biologics in MTX increasing group (n=16) was suppressed as same as PD negative group (0.75 and 0.80, respectively) at week 52.
Conclusions In conclusion, clinical remission according to composite indexes allowed the presence of subclinical active synovitis that might induce structural joint damages. Subclinical active synovitis should be controlled by additional treatment and this results in the prevention of the joint damage progression. Evaluation of subclinical active synovitis by using high resolution US should be important even in patients achieving clinical remission and it should be treated more intensively if active synovitis is positive.
Disclosure of Interest T. Okano: None declared, K. Inui: None declared, M. Tada: None declared, Y. Sugioka: None declared, K. Mamoto: None declared, T. Koike Grant/research support from: Takeda Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Chugai Pharmaceutical Co., Ltd., Eisai Co., Ltd., Abbvie GK, Teijin Pharma Ltd., MSD K.K. and Ono Pharmaceutical Co., Ltd, H. Nakamura: None declared