Objectives The presence of synovitis has been recognized as one of the most important predictive factors of subsequent structural damage in patients with rheumatoid arthritis (RA). We previously reported that the effects of low-dose etanercept (ETN) (25 mg/week) were not inferior to the effects of standard-dose ETN (50 mg/week) clinically, but in terms of the radiographic non-progression rate, the effects of low-dose ETN were inferior to the effects of standard-dose ETN in the PRECEPT study. It was considered that low-dose ETN may not be able to suppress inflammatory synovitis. The aim of this study was to compare ultrasonographic inflammatory synovitis between patients using standard- and low-dose ETN for RA.
Methods Patients with RA receiving standard- and low-dose ETN underwent musculoskeletalultrasonography (US) at 34 synovial sites (30 joints) in the following joints: bilateral first to fifth MCP joints (dorsal recess), first IP and second to fifth PIP (dorsal recess) joints, the wrists (dorsal radial, dorsal median, and dorsal ulnar) and second to fifth MTP (dorsal recess) joints. The gray scale (GS) and power Doppler (PD) signals were scored in each joint using a semiquantitative scale from 0 to 3. The GSUS and PDUS scores were compared with the sums of scores obtained for the 34 synovial sites and the maximum score between two groups.
Results We analyzed 31 and 21 patients who received standard- and low-dose ETN, respectively. The overall comparison showed no significant differences between groups. However, when we analyzed patients in remission and low disease activity, the PDUS score and maximum PD score were significantly higher in the low-dose ETN group. In particular, the PDUS score in wrist were significantly higher in the low-dose ETN group. But, GSUS score showed no significant difference between two groups. (Table 1)
Conclusions Low-dose ETN is not inferior to standard-dose ETN in terms of effects on clinical assessment. However, in terms of ultrasonographic inflammatory synovitis, the effects of low-dose ETN may be inferior to the effects of standard-dose ETN. We consider that synovitis may not be suppressed sufficiently, and therefore joint destruction may progress, in RA patients receiving low-dose ETN.
Disclosure of Interest K. Mamoto: None Declared, T. Koike Speakers bureau: akeda Pharmaceutical, Mitsubishi, T. Okano: None Declared, Y. Sugioka: None Declared, M. Tada Grant/research support from: Japan Osteoporosis Foundation grant 2013, K. Inui: None Declared, H. Nakamura: None Declared