Presence of power Doppler synovitis in rheumatoid arthritis patients with synthetic and/or biological disease-modifying anti-rheumatic drug-induced clinical remission: experience from a Chinese cohort

The aim of this study was to evaluate the ultrasonographic synovitis in rheumatoid arthritis (RA) patients who reached clinical remission. Two hundred and two RA patients were enrolled into this study. One hundred and eleven RA patients achieved clinical remission with the treatment of synthetic and/or biologic disease-modifying anti-rheumatic drugs (DMARDs). Subclinical synovitis was assessed by power Doppler ultrasonography (PDUS). PD synovitis was semi-quantitatively recorded. Twenty-two joint regions were imaged: bilateral wrists, metacarpophalangeal (MCP) joints, and proximal interphalangeal (PIP) joints. PD remission was defined as a total PD score of 0. The subclinical synovitis in the RA patients who achieved clinical remission was evaluated. The correlations between PD total scores and clinical/laboratory parameters were analyzed. Among the 111 RA patients who achieved clinical remission, 110 (99.1 %), 67 (60.4 %), 55 (49.5 %), 50 (45.0 %), and 54 (48.6 %) patients, respectively, satisfied DAS28 (CRP), DAS28 (ESR), CDAI, SDAI, and 2010 ACR/EULAR remission criteria. However, only 54 (48.6 %) patients achieved PD remission. Subclinical synovitis was detectable in 57 (51.8 %), 30 (44.8 %), 22 (40.0 %), 19 (38.0 %), and 18 (33.3 %) patients accordingly. On the contrary, 11 (26.8 %) out of 41 patients who fulfilled all five clinical remission criteria had evidence of subclinical synovitis. In those 91 patients who did not achieved clinical remission, total PD score was correlated with swollen joint counts (SJC), tender joint counts (TJC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and complex disease activity indexes (P < 0.01), but not the titers of rheumatoid factor and anti-cyclic citrullinated peptide. Among those 57 patients with subclinical synovitis after reaching clinical remission, no correlation was found between PD total score and SJC, TJC, ESR, CRP, and complex disease activity indexes. Presence of subclinical synovitis is common in patients achieving clinical remission. The stricter clinical remission criteria may reflect less PD synovitis. In patients with active RA, PD total score of synovitis was positively correlated with disease activity.