Hypokalemia as a sensitive biomarker of disease severity and the requirement for invasive mechanical ventilation requirement in COVID-19 pneumonia: A case series of 306 Mediterranean patients

Int J Infect Dis. 2020 Nov;100:449-454. doi: 10.1016/j.ijid.2020.09.033. Epub 2020 Sep 17.


Objectives: Serum levels of potassium (K+) appear to be significantly lower in severe cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the clinical significance of this is unknown. The objective was to investigate whether hypokalemia acts as a biomarker of severity in coronavirus disease 2019 (COVID-19) pneumonia and is associated with major clinical outcomes.

Methods: A retrospective cohort study of inpatients with COVID-19 pneumonia (March 3 to May 2, 2020) was performed. Patients were categorized according to nadir levels of K+ in the first 72 h of admission: hypokalemia (K+ ≤3.5 mmol/l) and normokalemia (K+ >3.5 mmol/l). The main outcomes were all-cause mortality and the need for invasive mechanical ventilation (IMV); these were analyzed by multiple logistic regression (odds ratio (OR), 95% confidence interval (CI)).

Results: Three hundred and six patients were enrolled. Ninety-four patients (30.7%) had hypokalemia and these patients showed significantly higher comorbidity (Charlson comorbidity index ≥3, 30.0% vs 16.3%; p = 0.02) and CURB65 scores (median (interquartile range): 1.5 (0.0-3.0) vs 1.0 (0.0-2.0); p = 0.04), as well as higher levels of some inflammatory parameters at baseline. After adjustment for confounders, hypokalemia was independently associated with requiring IMV during the admission (OR 8.98, 95% CI 2.54-31.74). Mortality was 15.0% (n = 46) and was not influenced by low K+. Hypokalemia was associated with longer hospital and ICU stays.

Conclusions: Hypokalemia is prevalent in patients with COVID-19 pneumonia. Hypokalemia is an independent predictor of IMV requirement and seems to be a sensitive biomarker of severe progression of COVID-19.

Keywords: COVID19 pneumonia; Cohort study; Hypokalemia; Mechanical ventilation; Mortality.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Betacoronavirus*
  • Biomarkers
  • COVID-19
  • Coronavirus Infections / blood
  • Coronavirus Infections / complications*
  • Coronavirus Infections / therapy
  • Female
  • Humans
  • Hypokalemia / epidemiology*
  • Male
  • Middle Aged
  • Pandemics
  • Pneumonia, Viral / blood
  • Pneumonia, Viral / complications*
  • Pneumonia, Viral / therapy
  • Respiration, Artificial*
  • Retrospective Studies
  • SARS-CoV-2
  • Severity of Illness Index


  • Biomarkers