Use and Spending for Biologic Disease-Modifying Antirheumatic Drugs for Rheumatoid Arthritis Among US Medicare Beneficiaries

ObjectiveBiologic therapies have assumed an important role in treating rheumatoid arthritis (RA). We sought to investigate use, spending, and patient cost-sharing for Medicare beneficiaries using biologic drugs for RA, comparing patients exposed to minimal cost-sharing because of a Part D low-income subsidy (LIS) to those facing substantial out-of-pocket costs (OOP). MethodsWe performed a retrospective, nationwide study using 2009 Medicare claims for a 5% random sample of beneficiaries with RA who had at least 1 RA drug dispensed. We analyzed biologic drug utilization and costs across the Part B (medical benefit) and Part D (pharmacy benefit) programs by LIS status using multinomial regression. We also projected OOP costs as the Affordable Care Act (ACA) mandates closure of the Part D coverage gap by 2020. ResultsAmong 6,932 beneficiaries, 1,812 (26.1%) received a biologic drug. LIS beneficiaries were significantly more likely to obtain Part D home-administered biologics (relative risk ratio [RRR] 2.98, 95% confidence interval [95% CI] 2.50-3.56), while non-LIS beneficiaries were less likely to receive Part D biologic agents (RRR 0.58, 95% CI 0.48-0.69). OOP costs in Part D were lower, as expected, for LIS beneficiaries ($72 versus $3,751 per year for non-LIS). Non-LIS beneficiaries had lower costs for Part B facility-administered biologic agents (range $0-$2,584) than for Part D home-administered biologic agents. ACA reforms will narrow OOP differences between Part D and B for non-LIS beneficiaries. ConclusionIn contrast to LIS beneficiaries who receive mostly Part D home-administered biologic DMARDs, nonsubsidized beneficiaries have significant cost-based incentives to obtain facility-administered biologic DMARDs through Part B. The ACA will result in only slightly lower costs for Part D biologic drugs for these beneficiaries.