Abstract
Background
Although Medicare Part D improved drug benefits for many beneficiaries, its impact on the coverage of Medicare Advantage Part D (MAPD) enrollees depended on their pre-existing benefits and whether they had gap coverage under Part D.
Objective
To examine changes in prescription drug utilization and expenditures associated with drug benefit changes resulting from the implementation of Part D.
Patients
We studied 248,773 continuously enrolled MAPD patients in eight states. Patients whose insurance product or Census block could not be identified or who had atypical benefits, low-income subsidies or Medicaid coverage were excluded.
Main Measures
The main outcomes were changes in prescription drug days supply and expenditures from 2005 to 2006 and 2005 to 2007.
Design
We linked Census data with 2005–7 MAPD claims, encounter, enrollment, and benefits data and estimated associations of the outcomes with changes in drug benefits, controlling for 2005 comorbidities, demographics, and Census population characteristics.
Key Results
MAPD enrollees whose drug benefits became potentially less generous after Part D had the smallest increases in drug utilization and expenditures (e.g., drug expenditures increased by $130 between 2005 and 2006), while those who potentially gained the most from Part D experienced the largest increases ($302). The differences in benefit design changes had a stronger association with drug utilization and outcomes among patients at high risk of gap entry than among the entire sample.
Conclusions
Although Medicare Part D unambiguously improved drug coverage for many elderly, it led to heterogeneous changes in drug benefits among MAPD enrollees, who already had generic and sometimes branded drug benefits. After 2006, benefits were worse for individuals who had branded drug coverage in 2005 but now had a coverage gap, but benefits may have improved for individuals who acquired branded drug coverage. Commensurate with these differential changes in benefits following Part D, changes in drug utilization and expenditures varied substantially as well.
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Acknowledgement
This project was funded by the Centers for Disease Control and Prevention, Cooperative Agreement U58/CCU923527-04-1: The Translating Research into Action for Diabetes (TRIAD) Study (PI: Mangione). Dr. Mangione is partially supported by the UCLA Resource Center for Minority Aging Research (NIA #P30AG021684-06). We would like to thank Ms. Deborah Marshall for manuscript preparation and other support, and the collaborating health plan for permitting access to the data. Dr. Mangione had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Conflict of Interest
In 2006, Dr. Ettner served as a one-time paid consultant for Lilly USA, LLC (“Lilly”) to answer questions about the literature on the cost-effectiveness of antipsychotic medications. In 2010, she served as a one-time paid consultant to Lilly to review the initial study protocol and proposed questionnaires for the Multinational Observational Study Advancing an understanding of the factors associated with differential treatment response and the role of Insulin in the care of patients with Type 2 Diabetes: The MOSAIc Type 2 Diabetes Study.
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ELECTRONIC SUPPLEMENTARY MATERIALS
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eTable 1
Sample Size Derivation (DOC 34 kb)
eTable 2
Summary of Changes to MAPD Drug Benefits Following the Implementation of the Medicare Part D Program (DOC 33 kb)
eTable 3
Adjusted Impact of Changes in Prescription Drug Benefits on Changes in Branded Drug Days Supply of Pills (DOC 34 kb)
eTable 4
Adjusted Impact of Changes in Prescription Drug Benefits on Changes in Branded Drug Expenditures (DOC 34 kb)
eTable 5
Adjusted Impact of Changes in Prescription Drug Benefits on Changes in Generic Drug Days Supply of Pills (DOC 34 kb)
eTable 6
Adjusted Impact of Changes in Prescription Drug Benefits on Changes in Generic Drug Expenditures (DOC 34 kb)
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Ettner, S.L., Steers, W.N., Turk, N. et al. Drug Benefit Changes Under Medicare Advantage Part D: Heterogeneous Effects on Pharmaceutical Use and Expenditures. J GEN INTERN MED 26, 1195–1200 (2011). https://doi.org/10.1007/s11606-011-1766-x
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DOI: https://doi.org/10.1007/s11606-011-1766-x