Elevated Admission Potassium Levels and 1-Year and 10-Year Mortality Among Patients With Heart Failure

Abstract

Background: Limited, contradictory data exist regarding the effect of hyperkalemia on both short- and long-term all-cause mortality among hospitalized patients with heart failure (HF).

Methods: We analyzed 4,031 patients who were enrolled in the Heart Failure Survey in Israel. The study patients were grouped into 3 different potassium (K) categories. Multivariate analysis was used to determine the association of potassium levels as well as 1- and 10-year all-cause mortality.

Results: A total of 3,349 patients (83%) had K < 5mEq/L, whereas 461 patients (11%) had serum K ≥ 5mEq/L but≤ 5.5mEq/L and 221 patients (6%) had K > 5.5mEq/L. Survival analysis showed that 1-year mortality rates were significantly higher among patients with K > 5.5mEq/L (40%) and those with serum K ≥ 5mEq/L but ≤ 5.5mEq/L (34%) compared to those with K < 5mEq/L (27%); (all log rank P < 0.01). Similarly, 10-year mortality rates among those with K > 5.5mEq/L were 92%, whereas among those with serum K ≥ 5mEq/L but ≤ 5.5mEq/L rates were 88%, and in those with K < 5mEq/L rates were 82%; (all log rank P < 0.001). Consistently, multivariate analysis showed that compared to patients with K < 5mEq/L, patients with K > 5.5mEq/L had an independently 51% and 31% higher mortality risk at 1 year and 10 years, respectively (1-year hazard ratio = 1.51, 95% CI: 1.04-2.2; 10-years hazard ratio = 1.31, 95% CI: 1.035-1.66), whereas patients with serum K ≥ 5mEq/L but ≤ 5.5mEq/L had comparable adjusted mortality risk to patients with K < 5mEq/L at 1 and 10 years.

Conclusions: Among hospitalized patients with HF, admission K > 5.5mEq/L was independently associated with increased short- and long-term mortality, whereas serum K ≥ 5mEq/L but ≤ 5.5mEq/L was not independently associated with worse outcomes.

Keywords: All-cause mortality; Heart failure; Hyperkalemia; Short-term and long-term outcomes.