Real world comparison of spironolactone and eplerenone in patients with heart failure.

Aims: In the absence of previous direct comparative studies, we aimed to evaluate the effectiveness of spironolactone and eplerenone in patients with heart failure and reduced ejection fraction (HFrEF) in a real-world clinical setting.

Methods: Using Fine-Gray´s competing risk regression, we compared the clinical outcomes of 293 patients with chronic HF and left ventricular ejection fraction <40% treated with eplerenone and 293 propensity-score matched individuals treated with spironolactone. Study subjects were selected from a prospective cohort of 1404 ambulatory patients with HFrEF seen since 2010 to 2019 in a single specialized HF clinic, among which 992 received a mineralocorticoid receptor antagonist at baseline. Median follow-up was 3.95 years.

Results: No statistically significant differences between patients treated with eplerenone versus spironolactone were observed with regard to the risk of the primary composite end-point cardiovascular death or HF hospitalization (HR 0.95; 95% CI 0.73-1.23; p= 0.677). However, eplerenone use was associated to lower cardiovascular mortality (HR 0.55; 95% CI 0.35-0.85; p= 0.008) and lower all-cause mortality (HR 0.67; 95% CI 0.47-0.95; p= 0.027). The incidence of drug suspension due to side effects (HR 0.58, 95% CI 0.40-0.85; p= 0.005) and drug suspension due to any reason (HR 0.70, 95% CI 0.51-0.97; p= 0.033) were lower among patients treated with eplerenone.

Conclusions: In this observational, real-world, propensity-score matched study of patients with HFrEF, eplerenone was associated to lower cardiovascular mortality and lower all-cause mortality than spironolactone.