MMP3 and rheumatoid arthritis: We found that MMP-3 had a similar ability to distinguish between the three RA groups and HCs: the AUCs were 0.917 (95% confidence interval [CI] 0.877–0.957; p < 0.01), 0.930 (95% CI 0.892–0.968; p < 0.01), and 0.923 (95% CI 0.891–0.956; p < 0.01), respectively.