Normal serum matrix metalloproteinase-3 levels can be used to predict clinical remission and normal physical function in patients with rheumatoid arthritis

This study aimed to evaluate whether normal serum matrix metalloproteinase-3 (MMP-3) levels can be used to predict clinical remission and normal physical function at a single time point when treating patients with rheumatoid arthritis (RA) in daily practice settings. Subjects were all 1321 RA patients who were treated at our hospital. The accuracy of serum MMP-3 levels was larger than those of C-reactive protein (CRP) levels for predicting clinical remission [Simplified Disease Activity Index (SDAI) ≤ 3.3], normal function [Disability Index of the Health Assessment Questionnaire (HAQ-DI) ≤ 0.5], and both in clinical remission and with normal function (clinical remission + normal function) using receiver operating characteristic curve analysis. Serum MMP-3 levels were significantly correlated with CRP levels [r 0.229 (men), r 0.476 (women)] using Pearson’s correlation coefficients. Among patients with normal CRP levels (n = 807), the percentage of patients in clinical remission, with normal function, and with clinical remission + normal function having normal serum MMP-3 levels was significantly higher than those with abnormal serum MMP-3 levels. In addition, among patients with the 28-point count Disease Activity Score-CRP (DAS28-CRP) remission (DAS28-CRP < 2.3), the percentage of patients in clinical remission, with normal function, and with clinical remission + normal function having normal serum MMP-3 levels was significantly higher than those with abnormal serum MMP-3 levels. Our findings suggest that normal serum MMP-3 levels, in combination with CRP levels or disease activity, are useful for predicting clinical remission and normal physical function in patients with RA.