PHS18 - Long-Term Costs Associated with Anti-Cyclic Citrullinated Peptide Positivity in Patients with Rheumatoid Arthritis

Abstract

Anti-cyclic citrullinated peptide (anti-CCP) positivity has been suggested to be a strong predictor of joint erosion and potential biomarker for guiding treatment decisions in rheumatoid arthritis (RA). This study aimed to evaluate the association between the anti-CCP positivity and long-term direct healthcare expenditures in newly diagnosed RA patients. A retrospective cohort study was conducted in adult RA patients within a US integrated healthcare delivery system (January 2007 to June 2015). Individuals entered the cohort on their first RA diagnosis date (index), and were followed until death, health plan disenrollment, or study end. Patient demographics, anti-CCP positivity at baseline, and healthcare resource utilization during follow-up were collected. Nationally recognized direct medical costs were assigned to healthcare utilization to calculate healthcare costs in 2015 US Dollars. The long-term cumulative mean differences in costs between anti-CCP positive and negative groups were compared accounting for censoring using inverse probability weighting. A total of 2,448 newly diagnosed RA patients were identified and followed for a median of 3.7 years. At baseline, 65.8% patients were anti-CCP positive. Anti-CCP positivity was associated with higher biologic DMARDs prescription (22.4% for anti-CCP(+) vs. 12.7% for anti-CCP(-), p<0.001), and rheumatologist utilization (median rheumatologist visits: 13 for anti-CCP(+) vs. 9 for anti-CCP(-), p<0.001). Total additional burden associated with anti-CCP positivity during the 4 years was $14,089 per person ($61,248 for anti-CCP(+) vs. $47,159 for anti-CCP(-), p<0.001). The annual incremental costs for anti-CCP(+) patients increased over time, from $2,163 during the first year to $5,062 during the fourth year. Most of the increased economic burden associated with anti-CCP positivity was from pharmacy expenditures. In newly diagnosed RA patients, anti-CCP positivity was associated with higher long-term economic burden. These results are consistent with the findings that anti-CCP positivity is associated with a poor prognosis and more destructive course of disease.