Risk of morbidity and mortality in patients with severe heart failure (HF) is reduced by blockade of aldosterone receptors with spironolactone. However, benefits of spironolactone are potentially limited by treatment compliance and adverse events profile. The aim of this study was to estimate use of spironolactone by patients with HF, incidence of key adverse events, and patient compliance.
This study was performed using data from the Quebec provincial medical and drug plans (Régie de l'Assurance Maladie du Québec, RAMQ) for patients who had a diagnosis of HF. Relative incidence of gynecomastia and hyperkalemia was estimated for users and non-users of spironolactone. Treatment adherence was estimated for users of spironolactone and compared to adherence with angiotensin converting enzyme (ACE) inhibitors, beta-blockers (β-blockers), and angiotensin receptor blockers (ARBs).
RAMQ data were obtained for a total of 82,018 patients with a diagnosis of HF. Of these patients, 59.9% used an ACE inhibitor, 59.5% used a beta-blocker, 28.4% used an ARB, and 15.1% (n = 12,344) used spironolactone. Despite underestimation due to limitation of the database, the documented incidence of hyperkalemia (3.3% versus 1.4%) and gynecomastia (1.8% versus 0.7%) was significantly higher in spironolactone users than non-users (p < 0.001). Treatment compliance was significantly lower with spironolactone compared to ACE inhibitors, β-blockers, and ARBs (45.6% versus 56.1%, 59.7%, and 57.0%, respectively; p < 0.001). Persistence to treatment over a one-year period was also lower with spironolactone compared to ACE inhibitors, β-blockers, and ARBs (50.7% versus 64.5%, 70.4%, and 66.3%, respectively; p < 0.001).
Use of spironolactone is associated with an incidence of adverse events, which may have an impact on treatment compliance.