June 10, 2019
Out-of-pocket spending for beta-blockers was significantly linked with a slight decline in medication adherence among Medicare Part D enrollees with heart failure, according to a study in the Journal of Managed Care & Specialty Pharmacy.
“This finding corroborates an earlier study in a commercially insured heart failure sample that found significantly increased odds of nonadherence for beta-blocker copays over $20,” researchers wrote. “It must be interpreted with caution, however, because most participants spent far less than 1% of their monthly income on a beta-blocker prescription.”
The finding stems from an analysis of drug spending and medication adherence among participants in the Medicare Current Beneficiary Survey. Researchers looked at data for community-swelling respondents with self-reported heart failure and Medicare Part D coverage. The study focused on beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and angiotensin II receptor blockers (ARBs).
Among participants, whose median monthly income was $1472, the average percent of monthly income spent on a month-long medical supply was 0.22% for beta-blockers, 0.19% for ACE inhibitors, and 0.90% for ARBs. Adherence, which was gauged using a medication possession ratio, was 88.9% for beta-blockers, 88.5% for ACE inhibitors, and 90.4% for ARBs, researchers reported.
Despite low out-of-pocket costs and overall high adherence, beta-blocker nonadherence was significantly associated with higher out-of-pocket costs. For every 0.1 increase in percentage of income spent on beta-blockers, the odds of nonadherence increased 4%, according to the study.
Out-of-pocket costs were not associated with adherence for either ACE inhibitors or ARBs.
“If out-of-pocket spending indeed predicts nonadherence to beta-blockers in this population, then limits on patient liability for beta-blockers relative to income may increase efficiency, should costs rise,” researchers wrote. “That is because adherence to heart failure treatment is associated with fewer hospitalizations, longer cardiac event-free survival, and lower cumulative Medicare spending. Moreover, copay-attributable nonadherence has been linked to increased risk of hospitalization in heart failure.”