Anti‐cyclic citrullinated peptide but not rheumatoid factor is associated with ultrasound‐detected bone erosion among rheumatoid arthritis patients with at least moderate disease activity

AIM To investigate anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) in relation to ultrasound-detected joint inflammation and bone erosion in patients with rheumatoid arthritis (RA) as previous studies have mainly utilized radiographic damage as imaging outcomes. METHOD In this cross-sectional study, patients were grouped based on their Disease Activity Score at 28 joints (DAS28  25th, >50th and >75th percentiles. RESULTS One thousand and eighty joints and 1800 joint recesses from 36 peripheral joint sites were scanned in 30 adult RA patients (mean disease duration, 70.3 months; 93.3% female; 93.3% anti-CCP positive; 93.3% RF positive). In the DAS28  7 (75th percentile) was 0.72 (sensitivity = 83.3%, specificity = 53.8%). CONCLUSION The association of anti-CCP and RF with joint damage appears to differ in RA. Among patients with at least moderate disease activity (DAS28 ≥ 3.2), anti-CCP-but not RF-is associated with joint damage, being moderately correlated with ultrasound-detected bone erosion.