Association of Anti-cyclic Citrullinated Peptide Antibodies with Clinical and Radiological Disease Severity in Rheumatoid Arthritis

Objective: This study assessed an association of anti-cyclic citrullinated peptide antibodies (ACPA) with clinical and radiological disease severity in patients with rheumatoid arthritis (RA). Materials and Methods: Fifty patients diagnosed with RA as per 2010 revised American College of Rheumatology/ European League Against Rheumatism (ACR/EULAR) classification criteria were included in this cross-sectional study. Serum levels of ACPA, C-reactive protein (CRP) and rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), disease activity score with 28-joint counts and ESR (DAS28-ESR), patient’s global assessment of disease activity using visual analogue scale (PtGA-VAS), modified health assessment questionnaire score (M-HAQ) and radiological damage in hands and feet (modified Larsen score) were determined. Results: ACPA were positive in 48 (96%) and RF in 44 (88%) patients. Mean Larsen score was 19.82 ± 17.11 and mean DAS28-ESR 6.39 ± 1.59. A significant correlation of ACPA levels was seen with RF (p=0.03) and Larsen score (p=0.02) but not with DAS28-ESR (p=0.17) and M-HAQ (p=0.81). A significant correlation was seen between Larsen score and disease duration (p<0.0001), age (p=0.04), DAS28-ESR (p=0.001) and M-HAQ (p<0.0001). Multivariate analysis showed that painful joint count (p=0.003), ESR (p<0.001) and PtGA-VAS (p=0.009) were independently associated with clinical disease activity severity. Disease duration (p=0.01), ACPA levels (p=0.004) and DAS28-ESR (p=0.03) were independently associated with radiological joint damage. Conclusion: Serum ACPA levels correlate significantly with radiological severity of RA but not with clinical disease severity and are independently associated with radiological outcome.