AB0314 Association of Rheumatoid Factor and Anti-Citrullinated Protein Antibody Status with Orthopedic Surgeries for Rheumatoid Arthritis Patients

Background Both rheumatoid factor (RF) and anti–citrullinated protein antibody (ACP) are associated with bone damage in rheumatoid arthritis (RA). However, there has been little investigation into whether these autoantibodies could interact and/or contribute to orthopedic surgeries for RA patients. Objectives To investigate the role of RF and ACP positivity status as a contributor to orthopedic surgeries for RA patients. Methods The study examined orthopedic surgery database with linkage to RF/ACP data set. Patients were categorized into the following four groups: double-positive (RF+ or high/ACP+ or high), RF+ or high/ACP- or low, RF- or low/ACP+ or high and double-negative (RF- or low /ACP- or low). Results Among 2,052 RA patients, 332 (16.2%) patients underwent orthopedic surgeries. Using receiver operating characteristics analysis, RF and ACP level to associate orthopedic surgeries were 34 IU/ml and 4.1 U/ml, respectively. 19.9% (244/1255), 19.7% (27/137), 14.3% (40/279) and 5.1% (21/411) of patients underwent orthopedic surgeries in RF high (RF>34 IU/ml)/ACP high (ACP>4.1 U/ml), RF high/ACP low, RF low/ACP high and RF low/ACP low patients, respectively (p<0.001). Next, we analyzed a total of 155 orthopedic surgical procedures of small joints (hand and forefoot). RF/ACP double positive was 87.7%, RF+/ACP- was 8.4%, RF-/ACP+ was 3.3% and double negative was 0.6%. Conclusions Concomitant presence of RF and ACP is associated with orthopedic surgeries. Our data suggest that RF may contribute to RA joint destruction regardless of the presence of ACP. Disclosure of Interest None declared