Blood aldosterone concentrations and effects of mineralocorticoid receptor antagonists in heart failure

Abstract Background and Aims Low-dose mineralocorticoid receptor antagonists (MRAs) are guideline-recommended heart failure (HF) therapies. However, MRAs increase aldosterone production, and the sub-saturating doses utilized may allow continued mineralocorticoid receptor (MR) stimulation. The aim of the current analysis was to understand how baseline and change in aldosterone concentrations during MRA therapy impacts MR activity and clinical outcomes. Methods HF cohorts with MRA exposure and plasma aldosterone concentrations available were included in patient-level, pooled cohort analyses [DOSE, CARRESS-HF, MDR, and TOPCAT (n = 1019)]. In the MDR cohort (n = 136), urine sodium to potassium ratio was utilized to quantitate MR activity. The relationship of pre-MRA aldosterone concentration, MRA use, and clinical outcomes were meta-analysed utilizing the above pooled cohorts in addition to the EARLIER (n = 300) and EPHESUS (n = 453) trials. Results MRA use was associated with significantly higher median aldosterone concentrations [MRA = 310 (interquartile range, IQR 180, 533) pg/mL vs no MRA = 174 (IQR 106, 299) pg/mL, P Conclusions Low-dose MRAs significantly increase aldosterone but inadequately block MR activity (measured by urine Na/K) at these new higher aldosterone concentrations. In patients with high pre-MRA aldosterone, MRA use is associated with improved MR activity and clinical outcomes. However, in patients with lower pre-MRA aldosterone concentrations, MRA use is associated with worsened MR activity and clinical outcomes. MRAs remain guideline-directed HF medications with established population level benefit, but these hypothesis-generating findings indicate additional research is warranted to understand if outcomes can be further improved.