Matrix metalloproteinase-3 and the 7-joint ultrasound score in the assessment of disease activity and therapeutic efficacy in patients with moderate to severe rheumatoid arthritis

Background: This study aimed to investigate the reliability and validity of serum matrix metalloproteinase-3 (MMP-3) levels and articular ultrasound (US) scores in assessing disease activity and therapeutic response in rheumatoid arthritis (RA) patients. Methods: A total of 151 RA patients were enrolled, of whom 22 were treated with certolizumab pegol (Cimzia, CZP). The RA patients were divided into the following four subgroups according to their disease activity score in 28 joints (DAS28): stable, mild activity, moderate activity, and high activity. Forty-three healthy controls were simultaneously studied. The serum MMP-3 levels and 7-joint US (US7) scores of all subjects were determined. The patients who were treated with CZP were subsequently followed for 6 months. Results: The serum MMP-3 levels of all the RA patients were significantly higher than those of healthy controls, and those of patients with moderate and severe RA were significantly higher than those of patients with stable RA. The US7 scores of patients with severe RA were significantly higher than those of patients in other groups. Using the DAS28 as a reference standard, the corresponding cutoff value of MMP-3 was 70.5 ng/ml. After CZP treatment, the MMP-3 levels and US7 scores were significantly decreased at week 2, and the mean changes in US7 scores at weeks 12 and 24 were significantly higher in both groups with American College of Rheumatology 50% positive response (ACR50) and ACR 70% positive response (ACR70) than in the negative groups. Conclusion: Serum MMP-3 and the US7 scores could both effectively reflect disease activity and therapeutic responses in patients with moderate to severe RA.