Comparative effectiveness of finerenone versus spironolactone in patients hospitalized with heart failure: a prospective cohort study

Background Finerenone has demonstrated cardiorenal benefits in clinical trials. However, real-world head-to-head comparisons with traditional mineralocorticoid receptor antagonist (MRA) in hospitalized heart failure (HF) populations remain limited. Purpose The objective of this study was to evaluate the effectiveness and safety of finerenone versus spironolactone in patients hospitalized for HF. Methods The prospective cohort enrolled 348 patients hospitalized with HF (NYHA class II–IV) who were initiated on either finerenone or spironolactone at discharge. The primary outcome was time to the composite of worsening HF events (HF readmission or intravenous diuretic use) and all-cause mortality. Secondary outcomes encompassed treatment discontinuation and medication-related safety events (hyperkalaemia, renal function deterioration and hypotension). Results The study population comprised 348 patients (median age 71 years; 63% male), the population spanned the left ventricular ejection fraction spectrum was as follow: LVEF <40%, 53.4%; 40–49%, 13.8%; ≥50%, 32.8%. 109 patients received finerenone (5–10 mg/day) and 239 received spironolactone (20 mg/day). Patients in the finerenone group exhibited a higher prevalence of chronic kidney disease stage 3-5 (43.1 % vs 28.0 %, p= 0.008). In contrast, the spironolactone group demonstrated a higher body mass index (24.4 vs 23.2 kg/m², p= 0.002) and a higher prevalence of atrial fibrillation (45.6 % vs 28.4 %, p= 0.004). The utilisation of HF medications was no signification disparities between the groups, except for more frequent use of SGLT2 inhibitors in the finerenone group (74.3 % vs 60.3 %, p= 0.010). The median follow-up period was 15 months. Inverse probability of treatment weighting was employed to address the imbalances at baseline. In the weighted cohort, the primary composite occurred less frequently in the finerenone group (hazard ratio [HR] 0.56, 95 % confidence interval [CI] 0.38–0.81, p< 0.001), primarily driven by fewer HF worsening events (HR 0.57, 95 % CI 0.38–0.83, p< 0.001). There was no difference in all-cause mortality between the groups (HR 0.62, 95 % CI 0.25–1.50, p= 0.227). Treatment discontinuation occurred less frequent in finerenone group (27.5 % vs 39.7 %, p=0.037). Renal worsening (19.8% vs 17.3%, p= 0.433), hyperkalaemia (1.2% vs 5.6%, p= 0.116), and hypotension (7.6% vs 9.5%, p= 0.84) were infrequent and did not differ significantly between groups. At the end of follow-up, renal function, as assessed by eGFR, exhibited superior preservation in the finerenone group (p= 0.023). No significant differences were observed in echocardiographic parameters, including left ventricular ejection fraction and left ventricular end-diastolic diameter. Conclusions In this real-world cohort of hospitalized HF patients, finerenone was associated with a reduced risk of worsening HF events and improved treatment persistence in comparison with spironolactone, with equivalent safety outcomes.