FRI0551 Evaluation of Change in Anti-Citrullinated Peptide Autoantibody Levels in Clinical Practice and Association with Resource Use

BackgroundTesting for anti-citrullinated peptide antibodies (ACPA) has become standard in RA diagnosis in clinical practice, partly due to improved assay specificity compared with detection techniques for antibodies against RF.1 ACPA concentration, beyond ACPA positivity, is indicative of more aggressive radiographic progression.2 However, there is limited information on the association between changes in ACPA levels in clinical practice and resource use measures.ObjectivesTo evaluate the association of changes in ACPA levels with resource use (durable medical equipment [DME] use/hospitalizations) in clinical practice.MethodsPatients enrolled in the Brigham and Women's Hospital Rheumatoid Arthritis Sequential Study (BRASS) Registry, established in 2003, were analysed. BRASS primarily comprises patients with established RA who were evaluated semi-annually for multiple, clinical patient-reported outcomes and resource utilization parameters. The current analysis is based on patients enrolled in the BRASS registry who had ACPA values at baseline and at follow-up visits. ACPA levels were measured by well-documented and validated ELISAs from Inova Diagnostics (San Diego, CA), until its discontinuation in 2011, and Euro-Diagnostica (distributed by IBL-America, Minneapolis, MN) thereafter. Annual mean ACPA change from baseline (CFB) to 12 months was calculated and categorized as decrease (1+ unit decrease), no change (>–1 to