Abstract 4765: The impact of the Medicare Part D donut hole closure on use and out-of-pocket costs for aromatase inhibitors
Authors: Graetz Ilana , Anderson Janeane N. , Kaplan Cameron M. 
Published: August 2018

Abstract
Objective: Nonadherence to adjuvant hormonal therapy among women with breast cancer increases with higher out-of-pocket costs, particularly among older women. In 2006, Medicare Part D was introduced to provide prescription drug coverage for Medicare beneficiaries, but it had a large coverage gap, also known as “donut hole.” In 2011, a provision of the Affordable Care Act was implemented to slowly eliminate the coverage gap, starting with a 50% reduction in brand-name drug pricing within the coverage gap. Also in 2011, several generic aromatase inhibitor (AI) medications became newly available to patients, further lowering their prescription drug costs. We examined whether the initial donut hole closure affected use of AIs and related out-of-pocket (OOP) costs.
Methods: We used a 5% sample of Medicare claims data for 2010 and 2011 (the first year of the donut hole closure) and included women ages 65 and older with a breast cancer diagnosis who filled one or more prescriptions for an AI in the first quarter of 2010 and had at least one AI fill in 2011. We used a difference-in-difference (DID) linear model to compare changes in the number of AI fills and OOP costs per fill between the standard population of individuals affected by the coverage gap to individuals who did not face the coverage gap because of low-income subsidies (LIS), adjusting for sociodemographic factors (e.g., race, age, dual status).
Results: Overall, 4,054 women filled an AI prescription in the first quarter of 2010 and had one or more fills in 2011; 37.59% received LIS, and thus were unaffected by the donut hole closure in 2011. After the initial donut hole closure, non-LIS beneficiaries had more AI fills (9.53 in 2011 versus 9.04 in 2010), and lower OOP costs per fill ($33.23 vs. $93.50). Conversely, LIS recipients filled fewer AIs in 2011 compared to 2010 (9.87 vs. 10.26) and had a smaller decrease in their OOP costs per fill ($2.96 vs. $4.40). The adjusted DID model estimates that after the initial prescription coverage gap closure, non-LIS Medicare beneficiaries had an additional 1.6 AI fills and $53.32 lower OOP costs per fill compared to LIS recipients (both p&lt;0.001).
Conclusion: The first year of the closure of the prescription drug coverage gap led to greater use of AIs and lower OOP costs for women with breast cancer affected by the policy. Whereas treatment nonadherence among women prescribed AIs is associated with increased risk of recurrence and mortality, findings from this analysis suggest that the donut hole closure and concurrent introduction of generic AIs to the market may increase treatment adherence and improve health outcomes for older women with breast cancer.
Citation Format: Ilana Graetz, Janeane N. Anderson, Cameron M. Kaplan. The impact of the Medicare Part D donut hole closure on use and out-of-pocket costs for aromatase inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4765.