Mineralocorticoid receptor antagonists in heart failure: real-world uptake, dose titration, hyperkalaemia trends, and potassium binder use

Background Guideline-directed medical therapy improves outcomes in heart failure, yet real-world implementation and adherence remain suboptimal, contributing to persistently poor survival. Hyperkalaemia is a frequent barrier to initiating and up-titrating prognostically important therapies, particularly mineralocorticoid receptor antagonists (MRAs), and may therefore limit treatment benefit. Purpose To evaluate the implementation of MRA therapy and patient-reported adherence, and to report the use of potassium binders in heart failure patients before and after publication of the 2021 ESC heart failure guidelines. Methods We performed a single-centre retrospective cohort study of heart failure patients treated between January 2016 and December 2025. Patients were stratified by index assessment before versus after release of the 2021 ESC heart failure guidelines (August 2021). We compared patient-reported adherence to MRAs and the use of potassium binders between periods. Continuous variables were analysed with t-tests and categorical variables with chi-square tests. Results A total of 712 patients were included: 278 (38%) in the pre-guideline and 434 (62%) in the post-guideline cohort. Sex distribution did not differ significantly (female: 48% vs 43%; p=0.247), while the post-guideline cohort was slightly younger (77±10 vs 75±10 years; p=0.025). Overall,MRA prescribing increased markedly after August 2021 (46% to 83%; p<0.001), alongside a significant rise in titration to target doses (14% to 35%; p<0.001). Consistent improvements were observed across individual MRA agents: spironolactone use increased from 42% to 60% (titrated: 11% to 23%; both p<0.001), eplerenone from 4% to 12% (p<0.001; titrated: 3% to 8%, p=0.076), and finerenone from 0% to 11%. Despite substantially higher MRA use, hyperkalaemia was less frequent in the post-guideline period (22% vs 11%; p<0.001). Potassium binders were rarely prescribed overall, but their use increased after guideline publication (1 patient pre-guidelines vs 23 patients post-guidelines; p<0.001). Conclusions Following publication of the 2021 ESC heart failure guidelines, MRA therapy, initiation as well as dose optimisation, improved substantially in routine care, without an associated increase in hyperkalaemia; in fact, rates of hyperkalaemia actually declined. Although potassium-binder prescribing increased, it remained infrequent, suggesting that barriers to their use and to systematic hyperkalaemia mitigation persist. Further efforts to standardise monitoring and proactive potassium management may help sustain safe MRA up-titration and maximise the clinical benefit of guideline-recommended therapy.