Correlation of Medication Adherence and Heart Failure Readmission Rates at the State Level For Medicare Beneficiaries in 2023

Abstract

Purpose: Heart failure (HF) remains a significant cause of morbidity and mortality in the US, with hospital readmissions contributing significantly to both patients’ burden and system costs. Guideline-directed medical therapy (GDMT), is a cornerstone of evidence-based HF management, however, variations in medication access, possession, and adherence may influence patient outcomes long term. This study evaluates national and state-level differences in GDMT medication possession and compares it to the incidence of HF readmissions. This analysis seeks to emphasize the Pharmacist’s role in promoting medication adherence to reduce avoidable HF-related hospitalizations.

Methods: This was a retrospective, cross sectional analysis of state-level possession rates of HF GDMT. GDMT possession data were obtained from the Centers for Medicare & Medicaid Services (CMS) Medicare Part D Prescribers by Geography and Drug dataset for the most recent available calendar year (2023). HF readmission rates, defined as 30-day all-cause readmissions following an index HF hospitalization, were collected from publicly available CMS Hospital Readmissions Reduction Program data. HF medications were angiotensin receptor-neprilysin inhibitors (ARNI), evidence-based beta-blockers (bisoprolol, carvedilol, metoprolol succinate), mineralocorticoid receptor antagonists (MRAs), or sodium-glucose cotransporter 2 (SGLT2) inhibitors. Medication adherence was estimated for each medication as the time of possession, and averaged across all HF medications. Descriptive statistics were used to summarize GDMT possession and HF readmission rates by state, and findings were presented in a comparative format to visualize possible trends.

Results: In 2023, nationally, MPRs differed by agent, with evidence-based beta-blockers (bisoprolol, metoprolol succinate, carvedilol) being between 78% and 82%, ARNI (sacubitril/valsartan) at 66%, SGLT2 inhibitors (dapagliflozin, empagliflozin) between 63% and 67%, and mineralocorticoid receptor antagonists (spironolactone, eplerenone) between 70% and 73%. The highest level of HF readmissions per 10,000 medicare enrollees was Washington DC (149 per 10k enrollees) while the lowest was Idaho (27 per 10k enrollees). Average MPRs for key GDMT agents ranged between 0.57–0.72. Washington DC had the lowest average MPR for GDMT medications (57%) while Wisconsin showed the highest (72%). The correlation between MPR and HF readmissions was -0.26.These ranges exclude Washington DC, which fell an average of ~10% below them. State-level MPRs showed 16% variability and despite large differences in readmission rates across states, no strong patterns emerged between MPRs and readmission outcomes given the narrow range of possession values.

Conclusion: The correlation between medication adherence and HF readmissions rates was negative, as expected, but weak. This suggests that factors beyond drug possession alone such as socioeconomic disparities, healthcare infrastructure, and adherence behaviors may play a role in driving differences in HF readmission rates. Medication access is important for improving patient outcomes and these results complement the complexity of Heart failure and reinforce the need for pharmacists in managing chronic disease states. Future work integrating clinical, demographic, and health system-level variables may provide more actionable insights into optimizing GDMT use and improving HF outcomes on a national scale.