Clinical Outcomes of Hospitalization for Severe Hyperkalemia in the Absence of Life-threatening Manifestations

Abstract

Introduction: Severe hyperkalemia warrants immediate hospitalization for patients with acute instability. However, the benefit of inpatient care in the absence of acute instability remains poorly defined. We therefore evaluated clinical outcomes across clinical settings for these patients. Methods: This two-center retrospective cohort study included outpatients presenting with severe hyperkalemia (serum potassium level [K+] ≥6.5 mEq/L). Among the initial cohort, our primary analysis focused on patients without life-threatening arrhythmias or other concurrent acute complications; the risk of 90-day all-cause mortality and hyperkalemia recurrence was compared between inpatient and outpatient management using overlap weighting. Results: A total of 554 patients with severe hyperkalemia were identified, comprising 276 inpatients and 278 outpatients. Median age was 75 (interquartile range [IQR] 65-83) years, 392 (71%) were male, and median K+ was 6.7 (IQR 6.5-7.0) mEq/L. In the analysis of 374 patients whose presentation was stable aside from the K+ elevation itself (99 inpatients and 275 outpatients), weighted logistic regression showed no significant difference in 90-day all-cause mortality between the two groups (odds ratio [OR] 1.39, 95% confidence interval [CI] 0.31-6.26); no hyperkalemia-specific deaths occurred. In contrast, outpatient management was associated with a significantly higher risk of hyperkalemia recurrence (OR 4.82, 95% CI 1.04-22.44). Conclusions: While outpatient management for severe hyperkalemia might be feasible for clinically stable patients in terms of short-term mortality, it carries a substantially increased risk of recurrence. Accordingly, hospitalization should generally be regarded as the preferred strategy.