The Impact of Medicare Part D on Medication Treatment of Hypertension

Objective

To evaluate Medicare Part D's impact on use of antihypertensive medications among seniors with hypertension.

Data Sources

Medicare‐Advantage plan pharmacy data from January 1, 2004 to December 12, 2007 from three groups who before enrolling in Part D had no or limited drug benefits, and a comparison group with stable employer‐based coverage.

Study Design

Pre–post intervention with a comparison group design was used to study likelihood of use, daily counts, and substitutions between angiotensin‐converting enzyme inhibitors and angiotensin‐II receptor blockers (ARBs).

Principal Findings

Antihypertensive use increased most among those without prior drug coverage: likelihood of use increased (odds ratio=1.40, 95 percent confidence interval [CI] 1.25–1.56), and daily counts increased 0.29 (95 percent CI 0.24–0.33). Proportion using ARBs increased from 40 to 46 percent.

Conclusions

Part D was associated with increased antihypertensive use and use of ARBs over less expensive alternatives.