Background/Purpose: Core disease activity indicators of rheumatoid arthritis (RA) have been found to be limited in predicting joint destruction progression. We previously reported that continuously elevated serum matrix metalloproteinase (MMP)-3 predicted one-year radiographic progression (RP) in RA patients. Here we aimed to develop a cutoff value of serum MMP-3 for clinical practice.

Methods: Consecutive patients with active RA (DAS28-CRP more than 2.6) were retrospectively recruited and divided into study cohort (naïve patients without previous DMARDs and corticosteroids treatment, n=102) and confirmatory cohort (others, n=140). Clinical data were collected at baseline and visits at month 1, 3, 6, and 12, and a change in modified total Sharp score more than 0.5 from the 12^th month to baseline was defined as RP.

Results: RA patients in study cohort had shorter disease duration but higher disease activity and HAQ-DI at baseline than that of patients in confirmatory cohort. However, there were significantly higher rate of remission and lower rate of RP in study cohort than that in confirmatory cohort (Table 1). In study cohort, patients in progressive group had higher serum MMP-3 at baseline than that in non-progressive group (P=0.014), whereas there was no different of CRP, ESR, RF, ACPA and DAS28-CRP between these two group (all P more than 0.05). ROC curve analysis showed that the area under the curve (AUC) of serum MMP-3 in predicting one-year RP was 0.671 with the cutoff value of 155ng/ml according to Youden index, whereas there was no significance of CRP, ESR, RF and ACPA (AUC: 0.491~0.570, all P more than 0.05). Univariate and multivariate logistic regression showed that baseline serum MMP-3 (more than 155ng/ml) was a significant predictor of one-year RP after adjusted for sex, age, disease duration, baseline DAS28-CRP and HAQ-DI (Table 2). This cutoff value of serum MMP-3 was validated by the confirmatory cohort (Table 2).

Conclusion: Elevated serum MMP-3 with a cutoff value of 155ng/ml is an applicable predictor for one-year RP in RA.

Fundings: This work was supported by National Natural Science Foundation of China (81471597, 81671612), Guangdong Natural Science Foundation (2017A030313576, 2017A030310236), Guangdong Medical Scientific Research Foundation (A2017109).