Brief Report: Anti–Citrullinated Protein Antibody Positivity Correlates With Cartilage Damage and Proteoglycan Levels in Patients With Rheumatoid Arthritis in the Hand Joints

Objective To investigate the factors associated with cartilage proteoglycan content in patients with rheumatoid arthritis (RA). Methods A total of 32 RA patients received high‐field 3T delayed gadolinium‐enhanced magnetic resonance imaging of cartilage (dGEMRIC) to determine cartilage proteoglycan content. Measurements were performed in 3 individual cartilage regions (medial, central, and lateral) of metacarpophalangeal (MCP) joints 2 and 3. T1 dGEMRIC values were then related to disease duration, disease activity, anti–citrullinated protein antibody (ACPA) status, rheumatoid factor (RF) status, and C‐reactive protein (CRP) level. Results T1 dGEMRIC values did not differ significantly between MCP joints 2 and 3. Intraclass correlation coefficients were high (>0.92) for all 3 cartilage compartments (medial, central, and lateral). T1 dGEMRIC values were significantly lower in RA patients with longer disease duration (≥3 years) (P = 0.034 for the central compartment) and those with ACPA positivity (P = 0.0002 for the central compartment, P = 0.013 for the lateral compartment). In contrast, no associations were found between cartilage proteoglycan content and disease activity, CRP level, or RF status. Conclusion Decreased cartilage proteoglycan content in RA patients is associated with disease duration and ACPA positivity but not with actual disease activity, CRP level, or RF status. These data suggest that the cumulative burden of inflammation as well as ACPAs are the determinants of cartilage damage in RA.