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Licensed Unlicensed Requires Authentication Published by De Gruyter February 22, 2021

Incidence, characteristics and outcomes among inpatient, outpatient and emergency department with reported high critical serum potassium values

Wei-Hung Kuo, Huey-Ling You, Wan-Ting Huang, Yueh-Ting Lee, Terry Ting-Yu Chiou, Hwee-Yeong Ng and Chien-Te Lee



Severe hyperkalemia can cause life-threatening arrhythmia, cardiac arrest, or death. This study aimed to investigate the incidence and the associated factors relevant to critical hyperkalemia (≥6 mmol/L) among inpatients, outpatients, and emergency department. Their clinical outcomes were also analyzed.


All patients whose high serum potassium values had been reported as critical laboratory values in 2016 were enrolled. Their demographic data, comorbidities, clinical symptoms, biochemical data, and outcomes were reviewed and collected. The Charlson comorbidity score (CCS) and glomerular filtration rate (GFR) were computed to assess the comorbidity burden and renal function. Patients were divided into groups according to different settings, potassium and GFR levels, and their survival.


Of the 293,830 total serum potassium tests, 1,382 (0.47%) reports were listed as critical laboratory values. The average reply time was 6.3 min. Their mean age was 67.2 years, while the average GFR was 12.2 mL/min/1.73 m2. The overall mortality rate was 34%. Patients in the emergency department had the highest incidence (0.92%), while inpatients had the worst outcome (51% mortality). The leading cause of mortality was septic shock. The fatal group had higher rates of clinical symptoms, higher potassium values, CCS, and eGFR (all p<0.05).


Most of the responses for the reports were obtained within a short period of time. Patients with reported high critical serum potassium values were characterized by high rates of comorbidity, reduced eGFR, and mortality. The incidence, clinical manifestations, and outcomes varied in the different clinical settings.

Corresponding author: Prof. Chien-Te Lee, Division of Nephrology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 123, Ta-Pei Road, Niao-Sung District, Kaohsiung833, Taiwan, Phone: +886 7 7317123, Ext. 8306, Fax: +886 7 7322402, E-mail:

  1. Research funding: None declared.

  2. Author contributions: Chien-Te Lee and Wei-Hung Kuo: conceived and designed the study, analyzed the data, and wrote the first draft of the manuscript; Yueh-Ting Lee: analyzed the data and edited the manuscript; Huey-Ling You and Wan-Ting Huang: provided laboratory data and edited the manuscript; Terry Ting-Yu Chiou and Hwee-Yeong Ng: edited the manuscript. All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  3. Competing interests: Authors state no conflict of interest.

  4. Ethical approval: The study was reviewed and approved by the Institutional Review Board of Chang Gung Memorial Hospital (201801819B0).


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Supplementary Material

The online version of this article offers supplementary material (

Received: 2020-10-05
Accepted: 2021-02-08
Published Online: 2021-02-22
Published in Print: 2021-06-25

© 2021 Walter de Gruyter GmbH, Berlin/Boston

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