LoboVault Home

Impact of the Medicare Part D coverage gap on prescription drug utilization and medication adherence

LoboVault

Please use this identifier to cite or link to this item: http://hdl.handle.net/1928/12101

Impact of the Medicare Part D coverage gap on prescription drug utilization and medication adherence

Show full item record

Title: Impact of the Medicare Part D coverage gap on prescription drug utilization and medication adherence
Author: Rupali, Naik
Advisor(s): Borrego, Matthew
Committee Member(s): Dodd, Melanie
Raisch, Dennis
Khan, Nasreen
Bakhireva, Ludmila
Gupchup, Gireesh
Department: University of New Mexico. College of Pharmacy
Subject: Medicare Part D
Coverage Gap
LC Subject(s): United States--Medicare Prescription Drug, Improvement, and Modernization Act of 2003--Health aspects.
Drugs--Prices--New Mexico--Health aspects.
Drug utilization--New Mexico-- Econometric models.
Pharmaceutical services insurance--Health aspects--New Mexico.
Medicare-Economic aspects--United States.
Degree Level: Doctoral
Abstract: The standard Medicare prescription drug benefit includes a coverage gap ($3,850 in true out-of-pocket expenses in 2007) during which beneficiaries pay 100% of their drug costs. The objective of this study was to assess the impact of the Medicare Part D coverage gap on prescription drug utilization and medication adherence by using data from Medicare beneficiaries enrolled in a large health plan in New Mexico. A quasi-experimental, cross-sectional, retrospective, pre-post with control group study design was used to assess the study objectives. Pre- and post-coverage gap prescription drug utilization and medication adherence, of beneficiaries enrolled in a health plan with no prescription drug coverage during the coverage gap (no coverage plan) was compared with that of beneficiaries enrolled in a plan with generic drug coverage (generic coverage plan) and beneficiaries enrolled in a plan with full prescription drug coverage during the coverage gap (full coverage plan). Pre- and post-coverage gap prescription drug utilization was assessed using per member total number of prescriptions. Medication Possession Ratio (MPRm) and the Proportion of Days Covered (PDC) were used as measures of medication adherence. Difference-in-difference analysis was used to compare pre- and post-coverage gap prescription drug utilization and medication adherence between the three plans. Of the 14,846 beneficiaries who met the study inclusion and exclusion criteria, 2,661 beneficiaries (17.92%) hit the prescription coverage gap in the year 2007. Difference-in-difference analyses indicated that post-coverage gap, beneficiaries enrolled in the no coverage gap plan, filled significantly less number of prescriptions (14.67 prescriptions less; p=0.001) than beneficiaries in the full coverage plan, and generic coverage plan (12.52 prescriptions less; p=0.001). A significant decrease in post-coverage gap medication adherence was observed between beneficiaries in the no coverage versus full coverage plans for beneficiaries on statins (5.8%), ARB’s (16%) and PPI’s (18.1%) when measured using the PDC as a measure of adherence. Similarly, a decrease in post-coverage gap medication adherence was observed between beneficiaries in the no coverage versus generic coverage plans for beneficiaries on statins (1.1%) and ARB’s (12%) when measured using the PDC as a measure of adherence. No significant post-coverage gap differences were observed between beneficiaries enrolled in the full coverage plan and generic coverage plan for any of the drug classes. In conclusion, the results of this study indicate that lack of prescription drug coverage during the Medicare Part D coverage gap leads to decreased utilization and adherence to certain essential prescription drugs.
Graduation Date: December 2010
URI: http://hdl.handle.net/1928/12101


Files in this item

Files Size Format View
FINAL_Rupali_Dissertation.pdf 1003.Kb PDF View/Open

This item appears in the following Collection(s)

Show full item record

UNM Libraries

Search LoboVault


Browse

My Account