Relationship Between Bone Mineral Density and Anti-citrullinated Protein Antibody and Rheumatoid Factor in Patients with Rheumatoid Arthritis

Objective: Rheumatoid arthritis (RA) is one of the causes of osteoporosis, and it leads to systemic bone loss. The anti-citrullinated protein antibody (ACPA) and rheumatoid factor (RF) are associated with local and systemic low bone mineral density and osteoclast-mediated bone resorption independently of inflammation in patients with RA. In this article, we aimed to evaluate the relationship between the ACPA, RF, and systemic bone mineral density in patients with RA.

Methods: Ninety-three patients (6 male, 87 female) with RA were included in the study. The disease activity score 28-erythrocyte sedimentation rate and titers of RF, ACPA, and bone mineral density of the total hip, femoral neck, and lumbar areas were evaluated. The independent samples t-test, Mann-Whitney U-test, Spearman's correlation, and multivariable regression analysis were used for the statistical analysis.

Results: The RF and ACPA were positive in 40.9% and 48.4% of patients with RA, respectively. Disease activity was negatively correlated with the T- and Z-scores. The T- and Z-scores were lower in the seropositive group than in the seronegative group. The ACPA was negatively correlated with the T- and Z-scores of the femoral neck. There was a significant difference for the Z-score of the femoral neck in patients with ACPA and RF-positive patients compared to seronegative patients with RA.

Conclusion: A low bone mineral density, especially in the femoral neck, is associated with the presence of ACPA and RF. It would be a more appropriate approach to carefully monitor osteoporosis in seropositive RA patients.