Diuretic and renal effects of spironolactone and heart failure hospitalizations: a TOPCAT Americas analysis

AIMS It is unclear whether spironolactone reduced heart failure (HF) hospitalizations in the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial through potential diuretic or other effects. We examined the effects of spironolactone on weight, diuretic use, and renal function, and their subsequent impact on outcomes. METHODS AND RESULTS We analysed data from TOPCAT Americas (1767 patients with HF and preserved ejection fraction; 886 in spironolactone, 881 in placebo arm). We used mixed-effects models for serial data and shared frailty models to identify determinants of recurrent HF hospitalizations among baseline and serial parameters. There were 800 HF hospitalizations after a median of 3.0 years. Despite more weight loss with spironolactone initially, weight trajectories overlapped after 12 months. Daily furosemide dose (time-averaged Δ: -4.8% vs. +11.6%, P