Cost-effectiveness of providing full drug coverage to increase medication adherence in post-myocardial infarction Medicare beneficiaries

Abstract

Background: Effective therapies for the secondary prevention of coronary heart disease-related events are significantly underused, and attempts to improve adherence have often yielded disappointing results. Elimination of patient out-of-pocket costs may be an effective strategy to enhance medication use. We sought to estimate the incremental cost-effectiveness of providing full coverage for aspirin, beta-blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and statins (combination pharmacotherapy) to individuals enrolled in the Medicare drug benefit program after acute myocardial infarction.

Methods and results: We created a Markov cost-effectiveness model to estimate the incremental cost-effectiveness of providing Medicare beneficiaries with full coverage for combination pharmacotherapy compared with current coverage under the Medicare Part D program. Our analysis was conducted from the societal perspective and considered a lifetime time horizon. In a sensitivity analysis, we repeated our analysis from the perspective of Medicare. In the model, post-myocardial infarction Medicare beneficiaries who received usual prescription drug coverage under the Part D program lived an average of 8.21 quality-adjusted life-years after their initial event, incurring coronary heart disease-related medical costs of $114,000. Those who received prescription drug coverage without deductibles or copayments lived an average of 8.56 quality-adjusted life-years and incurred $111,600 in coronary heart disease-related costs. Compared with current prescription drug coverage, full coverage for post-myocardial infarction secondary prevention therapies would result in greater functional life expectancy (0.35 quality-adjusted life-year) and less resource use ($2500). From the perspective of Medicare, full drug coverage was highly cost-effective ($7182/quality-adjusted life-year) but not cost saving.

Conclusions: Our analysis suggests that providing full coverage for combination therapy to post-myocardial infarction Medicare beneficiaries would save both lives and money from the societal perspective.

Figure 1

Cost-effectiveness model structure.□ Represents the choice between full coverage and current coverage. In each 1-year cycle, patients may experience 6 possible events (*) from which they may survive or die. At the end of the cycle, patients are left in 1 of 5 possible Markov states. In the subsequent cycle, patients may once again experience ≥1 event.

Figure 2

Cumulative changes in healthcare costs and survival for full coverage vs current drug coverage from the societal (A) and Medicare (B) perspectives. Data are presented as the change in CHD costs and mortality for patients receiving full drug coverage vs current levels of drug coverage.

Figure 3

Impact of annual drug costs on cost savings from full drug coverage. The thin arrow indicates the average drug cost ($212 per drug per year) used in the base-case analysis. The thick arrow indicates the threshold cost ($492) at which full drug coverage transitions from reduced to increased total costs. All future costs are discounted at a rate of 3%.