Matrix Metalloproteinases-3 Baseline Serum Levels in Early Rheumatoid Arthritis Patients without Initial Radiographic Changes: A Two-Year Ultrasonographic Study.

Objective: To investigate the association of high baseline serum levels of metalloproteinases-3 (MMP-3) with structural damage to hand and feet joints, assessed by ultrasonography (US), in patients with early, treatment-naïve rheumatoid arthritis (RA), without initial X-ray-visible erosions, during 24 months follow-up.

Methods: Sixty-three early RA (European League Against Rheumatism/American College of Rheumatology 2010), disease-modifying anti-rheumatic drugs/glucocorticoid naïve patients (mean age 53.4 ± 14.1) with symptom duration ≤12 months, had baseline serum levels of MMP-3 tested. OMERACT US group definition was used to detect the presence, as well as longitudinal diameter of erosions by US at study entry and after 24 months, at the level of wrists, metacarpophalangeal (MCP2/MCP5) joints of both hands, and fifth metatarsophalangeal joints.

Results: Complete data were collected from 52 out of 63 patients. High baseline serum levels of MMP-3 (MMP-3-positive) were found in 46/63 patients. 122 bone erosions in total (1.9 bone erosions/patients) were detected by US at baseline visit and 213 erosions (4.3/patients) after 24 months. MMP-3 positive patients had significantly higher total number of erosions than MMP-3-negative (p = 0.039) and higher increase in size of bone erosions in the feet but not in the hand joints after follow-up (OR 4.82 [1.23-18.9], p = 0.024; OR 1.17 [0.320-4.26], p = 0.816 respectively).

Conclusion: After 2 years of follow-up, US assessment showed a higher number of new bone erosions in MMP-3-positive compared to MMP-3-negative patients with early RA and no visible initial radiographic changes. High baseline levels of MMP-3 predict significantly higher structural damage progression at the level of feet, but not at the level of hand joints.