Temporal trends in use of biologic DMARDs for rheumatoid arthritis in the United States: A cohort study of publicly and privately insured patients

Abstract

BACKGROUND: Ten biologic disease-modifying antirheumatic drugs (bDMARDs) are available as treatment for rheumatoid arthritis (RA), but relatively little is known about population-level time trends in the use of these agents. OBJECTIVE: To describe time trends in the use of bDMARDs in RA patients with private or public insurance in the United States. METHODS: Claims data from private (Optum Clinformatics, 2004-2015) and public (Medicaid Analytic eXtract [[]MAX], 2000-2010) insurance programs were used. Patients with RA diagnosis codes and continuous health plan enrollment for 1-year baseline and 1-year follow-up periods were identified into 2 separate cohorts: (1) patients not using any bDMARD or (2) patients using a single bDMARD during the baseline period. Initiation of the first bDMARD from group 1 and switch to a second bDMARD from group 2 was identified as the outcome of interest during the 1-year follow-up period. Using mixed-effects regression models, we calculated yearly rates of initiation and switch for bDMARDs, adjusted for case-mix. We also described the proportion of all initiations and switches accounted for by each agent. RESULTS: There were 113,031 RA patients with public insurance and 97,751 RA patients with private insurance who were included in the study. The rates of initiation of bDMARDs (per 100 patients) increased significantly over time in Medicaid data for incident RA patients (from 1.1 to 3.1, P = 0.0006) and prevalent RA patients (from 4.6 to 10.9, P = 0.008). In Optum Clinformatics data, the rates were stable, with 7.7 to 8.3 per 100 incident RA patients (P = 0.10) and 11.0 to 11.5 per 100 prevalent RA patients (P = 0.12). The rates of switching (per 100 patients) increased over time from 6.4 to 16.0 (P = 0.04) in Medicaid data and 9.1 to 17.0 (P = 0.00003) in Optum Clinformatics data. Use of etanercept as the most common first-line agent was stable at approximately 50[%] of all biologic initiations, but use of infliximab decreased and the use of newer agents increased. CONCLUSIONS: More RA patients used bDMARDs in recent years, and use of newer agents, including certolizumab, golumumab, and tocilizuamab, is rising, which highlights a need for further comparative safety and effectiveness research of these agents to better guide evidence-based decision making.