Hyperkalemia and its Association With Mortality, Cardiovascular Events, Hospitalizations, and Intensive Care Unit Admissions in a Population-Based Retrospective Cohort

Ingrid Hougen; Silvia J Leon; Reid Whitlock; Claudio Rigatto; Paul Komenda; Clara Bohm; Navdeep Tangri

doi:10.1016/j.ekir.2021.02.038

Hyperkalemia and its Association With Mortality, Cardiovascular Events, Hospitalizations, and Intensive Care Unit Admissions in a Population-Based Retrospective Cohort

Kidney Int Rep. 2021 Mar 17;6(5):1309-1316. doi: 10.1016/j.ekir.2021.02.038. eCollection 2021 May.

Authors

Ingrid Hougen¹, Silvia J Leon^{2

3}, Reid Whitlock², Claudio Rigatto^{1

2

3}, Paul Komenda^{1

2

3}, Clara Bohm^{1

2

3}, Navdeep Tangri^{1

2

3}

Affiliations

¹ Department of Internal Medicine, Max Rady College of Medicine, University of Manitoba. Winnipeg, Manitoba, Canada.
² Chronic Disease Innovation Center, Seven Oaks General Hospital, Winnipeg, Manitoba, Canada.
³ Department of Community Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.

Abstract

Introduction: Hyperkalemia is a common, potentially life-threatening condition in patients with chronic kidney disease (CKD). We studied the association between hyperkalemia and mortality, cardiovascular events, hospitalizations, and intensive care unit (ICU) admissions.

Methods: We performed a retrospective cohort study using administrative databases in Manitoba, Canada. All adults (≥18 years of age) with potassium tests between January 2007 and December 2016 were included, with follow-up until March 31, 2017. Propensity score matching was performed among patients with de novo hyperkalemia (serum potassium ≥ 5.0 mmol/l) and patients who were nonhyperkalemic. The association between hyperkalemia and normokalemia and mortality was assessed using multivariate Cox proportional hazards regression models, adjusting for patient characteristics in a 1:1 propensity score-matched sample. Secondary outcomes included cardiovascular events, hospitalizations, and ICU admissions. A sensitivity analysis was performed with hyperkalemia defined as serum potassium ≥ 5.5 mmol/l.

Results: Of 93,667 patients with de novo hyperkalemia, 36% had diabetes mellitus (DM), 28% had CKD, and 21% had heart failure (HF). In the propensity score-matched sample of 177,082 individuals, hyperkalemia was associated with an increased risk for all-cause mortality (hazard ratio [HR] 1.15 [95% confidence interval {CI} 1.13-1.18], P < 0.001), cardiovascular events (HR 1.20 [95% CI 1.14-1.26], P < 0.001), short-term mortality (odds ratio [OR] 1.29 [95% CI 1.24-1.34], P < 0.001), hospitalizations (OR 1.71 [95% CI 1.68-1.74]), and ICU admissions (OR 3.48 [95% CI 3.34-3.62], P < 0.001). Findings were unchanged when a threshold of serum potassium ≥ 5.5 mmol/l was used.

Conclusion: Hyperkalemia was an independent risk factor for all-cause mortality, cardiovascular events, hospitalizations, and ICU admissions. This finding expands our understanding of important clinical outcomes associated with hyperkalemia.

Keywords: diabetes; hyperkalemia; kidney disease; mortality; population.