The impact of Medicare Part D on medication treatment of hypertension

Abstract

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.

Figure 1

Proportion of Members Filling an Angiotensin-Converting Enzyme (ACE) or Angiotensin-II Receptor Blockers (ARB) Each Year among Those Who Filled Either [Table: see text]