Spironolactone in the Treatment of Heart Failure with Mildly Reduced or Preserved Ejection Fraction: Design and Baseline Characteristics of the SPIRIT-HF-DZHK08 Trial

Abstract Aims This report describes the design and baseline characteristics of the SPIRIT-HF trial and compares them with prior heart failure with mildly reduced or preserved ejection fraction (HFpEF/HFmrEF) trials. Methods and Results In this multicenter, double-blind, placebo-controlled phase III trial, 730 patients aged ≥50 years with left ventricular ejection fraction (LVEF) ≥40%, New York Heart Association (NYHA) class II-IV symptoms, and either elevated N-terminal-pro-B-type natriuretic peptide (NT-proBNP) or HF hospitalization within 12 months were randomized 1:1 to spironolactone or placebo. The primary endpoint is a composite of rate of total (first and recurrent) HF hospitalizations and cardiovascular death within 24 months from randomization, which will be analyzed using the LWYY model. Secondary endpoints in a hierarchical order include total HF hospitalizations, CV hospitalizations, all hospitalizations, and cardiovascular death within 24 months from randomization. Results will first be analyzed based on the SPIRIT-HF dataset only. Then, a pre-specified individual participant data meta-analysis combining SPIRIT-HF and TOPCAT Americas will be conducted to refine treatment effect estimates. The median age of the patients enrolled in the SPIRIT-HF was 77.8 years, and 52% were women. The median LVEF was 55% (50-60), with 18% of patients having a LVEF between 40-49%. In SPIRIT-HF, prior HF hospitalization was similarly frequent (46.4% vs. 55%), but NT-proBNP was slightly higher (970 vs. 900 pg/ml) compared to TOPCAT Americas. However, the proportion of patients with NYHA class III (33% vs. 35%), patients with comorbidities such as atrial fibrillation at baseline electrocardiogram (25% vs. 25%) and chronic kidney disease (50% vs. 48%); and background therapy, such as beta-blockers (76% vs. 79%), and diuretics (83% vs. 89%), including loop diuretics (69% vs. 78%), were similar between SPIRIT-HF and TOPCAT Americas. Compared with prior HFpEF/HFmrEF trials, SPIRIT-HF patients demonstrated a higher risk with a similar proportion of patients with recent HF hospitalization (46.4%) and slightly higher NT-proBNP concentrations (970 pg/ml) at baseline. Conclusion SPIRIT-HF addresses key evidence gaps for spironolactone in high-risk HFpEF/HFmrEF, and could inform guideline recommendations on MRA use in this cohort.