Adherence to aldosterone-blocking agents in patients with heart failure.

The use of aldosterone blockers in the pharmacologic therapy for heart failure (HF) in patients with left ventricular systolic dysfunction has been shown to significantly reduce overall mortality, sudden cardiac death, and hospitalization. Patient adherence to polypharmaceutical regimens including aldosterone blockade and other key medication components is a concern for clinicians and their patients. A retrospective cohort study was conducted using integrated US pharmacy/medical claims covering 44.5 million lives. Inclusion criteria included the following: age at least 50 years, newly prescribed spironolactone or eplerenone from 2002 to 2006, with HF diagnosis within 12 months of prescription initiation and follow-up of at least 6 months to assess outcomes (12 months for adherence). Compliance was measured as the proportion of days covered (prescription days supply in the first year postindex for 365 days), and persistence was measured as days from the first to the last prescription. Of 388,523 patients with HF, 60,183 patients (15.5%) received an aldosterone blocker (n = 2024 for eplerenone, n = 58,159 for spironolactone), from which a newly treated subset was studied (n = 568 eplerenone, n = 11,982 spironolactone). Proportion of days covered was significantly greater for eplerenone (79% ± 42%) than for spironolactone (66% ± 42%, P < 0.01). Persistence was significantly higher for eplerenone than for spironolactone (P < 0.01) with discontinuation before 1 year at 49.5% and 73.7%, respectively. This analysis shows that a majority of patients did not receive an aldosterone blocker after HF diagnosis despite cardiovascular event risks and raises the hypothesis that eplerenone is associated with higher compliance and persistence as compared with spironolactone.