Patterns of spironolactone management following hyperkalemia among hospitalized patients with heart failure and reduced ejection fraction: a retrospective single-center study.

BACKGROUND: Heart failure with reduced ejection fraction (HFrEF) is a major cause of morbidity and mortality worldwide. Hyperkalemia is a common complication of chronic spironolactone therapy and may necessitate dose reduction or discontinuation, particularly in patients with impaired renal function. This study aimed to describe real-world spironolactone management patterns following the occurrence of hyperkalemia, evaluate guideline-directed medical therapy (GDMT) exposure (receipt of ≥3 drug classes), and explore factors associated with in-hospital mortality among hospitalized patients with HFrEF and hyperkalemia receiving chronic spironolactone therapy. METHODS: This retrospective single-center study included 146 adult HFrEF patients on spironolactone (May-Dec 2023). Data on demographics, comorbidities, renal function, GDMT exposure, and outcomes were extracted from electronic records. Hyperkalemia was categorized as mild-moderate (5.0-5.5 mmol/L) or severe (>5.5 mmol/L). Univariate logistic regression and multivariable Cox models identified predictors of in-hospital mortality. Kaplan-Meier analysis compared survival by GDMT exposure. RESULTS: The study cohort (N = 146) had a mean age of 58.34 ± 12.89 years, with 74% having hypertension and 23% having chronic kidney disease. Among the included HFrEF patients receiving chronic spironolactone therapy and admitted with hyperkalemia, 87% had mild-moderate and 13% had severe hyperkalemia at admission. Among the 136 patients with documented spironolactone management decisions, therapy was continued at the same dose in 13.2% of patients, dose reduced in 28.7%, and discontinued in 58.1%. Among patients with available follow-up potassium measurements, continuation of spironolactone at the same dose and dose reduction were associated with significant reductions in serum potassium levels over 72 h (p = 0.04 and p < 0.001, respectively), whereas discontinuation showed no significant change (p = 0.18). In exploratory multivariable Cox regression analysis, increasing age (HR 1.05, 95% CI 1.01-1.10, p = 0.02) and chronic kidney disease (HR 2.10, 95% CI 1.05-4.20, p = 0.03) were associated with higher in-hospital mortality. NYHA class III-IV showed a higher hazard estimate but did not reach statistical significance (HR 1.55, 95% CI 0.95-2.80, p = 0.08). In a separate exploratory adjusted analysis, receipt of ≥3 GDMT classes yielded a lower hazard estimate for in-hospital mortality (adjusted HR 0.62, 95% CI 0.21-1.80); however, this association did not reach statistical significance (p = 0.30). CONCLUSIONS: In this retrospective cohort of hospitalized patients with HFrEF and hyperkalemia, spironolactone management most commonly involved dose reduction or discontinuation following hyperkalemia. Older age and chronic kidney disease were associated with higher in-hospital mortality in exploratory analyses, whereas receipt of ≥3 GDMT classes was associated with a lower adjusted hazard estimate that did not reach statistical significance. Overall, these findings are exploratory and hypothesis-generating and should be interpreted cautiously given the retrospective single-center design, the limited number of mortality events, and the potential for residual confounding.