Positivity in serum MMP-3 after clinical remission or low disease activity at 52 weeks leads to future joint destruction in patients with rheumatoid arthritis

Introduction This study aimed to evaluate whether a long-term increase in serum matrix metalloproteinase-3 (MMP-3) levels leads to joint destruction in rheumatoid arthritis (RA) patients with negative serum C-reactive protein (CRP) values after methotrexate (MTX) therapy. Methods Patients with RA (n = 182) whose CRP values became negative due to MTX therapy were divided into two groups based on their MMP-3 positivity at the end of the observation period, and the 1-year progression of joint destruction was retrospectively compared. Radiological joint destruction was assessed using the modified van der Heijde total sharp score (mTSS). Results Among 109 (MMP-3(−), n = 63; MMP-3(+), n = 46) patients who achieved low disease activity or clinical remission (28 joint disease activity score erythrocyte sedimentation rate < 2.6), joint destruction (ΔmTSS ≥ 0.5) progressed in 24.6% and 48.9% of the MMP-3(−) and MMP-3(+) groups (p < 0.01), respectively. Prednisolone-induced increases in serum MMP-3 levels also resulted in joint destruction. Conclusion To prevent progressive joint destruction, the target MMP-3 value is 49.7 ng/mL in female patients, which is below the current MMP-3 cutoff value of 59.7 ng/mL. Residual MMP-3 activity may lead to the progression of joint destruction in patients with RA, even after CRP normalization by successful treatment with MTX.