Low potassium levels in COVID-19 disease

The currently spreading COVID-19 pandemic has been found to present in various ways, often with respiratory symptoms, but also with significant gut symptoms, skin symptoms, and in critical illness, multi-organ dysfunction may occur. Now a new study by an Italian team of researchers published in June 2020 on the preprint server medRxiv* reports that potassium levels are often low in COVID-19 disease, mostly due to the urinary loss of potassium.

The incidence of severe or critical COVID-19 is known to be higher among older patients and those with underlying medical conditions, including diabetes, cardiovascular disease, and obesity. These patients often need to remain in hospital for supportive medical care for weeks, with various needs ranging from mechanical ventilation to cytokine inhibitors to reduce hyperactive inflammation.

Study: Hypokalemia in Patients with COVID-19. Image Credit: Stephen Barnes / Shutterstock
Study: Hypokalemia in Patients with COVID-19. Image Credit: Stephen Barnes / Shutterstock

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

Hypokalemia is Common in COVID-19

Both the protean manifestations of sickness, as well as the side effects of the medications used can cause electrolyte imbalance. Accordingly, the current study shows that hypokalemia, or low potassium levels in the blood, occurs quite commonly. This is a concerning issue since, below a certain threshold, low potassium levels can lead to abnormalities of the heart rhythm, sometimes fatal.

The exact reasons for the development of hypokalemia are not clear, but several have been proposed. These include activation of the renin-angiotensin system, loss of potassium through the gut, loss of appetite and poor diet due to the infection, and kidney damage, perhaps due to direct viral cytotoxicity on tubular cells.

The current study focused on describing the incidence, impact, and mechanism of causation of hypokalemia on hospitalized COVID-19 patients. There were 1,671 blood samples, collected from 290 patients. Among these, 171 had normal potassium levels and were selected to be a control group.

Low potassium was present in 119 patients, accounting for 41% of the sample. The serum potassium levels ranged from 2.4 mEq/l to 3.5 mEq/l with a mean of 3.1 mEq/l. Most patients in this group had mild hypokalemia (about 91%), occurring along with hypocalcemia, and lower average magnesium levels.

Clinical Characteristics of Hypokalemic Patients

This group of patients also required a more extended period of follow-up, probably because the disease took a more severe form. In less than 40%, the urine potassium-to-creatinine ratio was measured and found to be over 1.5 mEq/mmol in over 95% of them. This indicates a high potassium excretion in urine.

Half of these 45 patients were on diuretics, and a quarter on steroids when potassium in serum was measured. Of the remaining quarter, 90% had low sodium excretion, while all of them had normal serum magnesium levels. Most of them were in metabolic alkalosis, with the remaining 30% equally distributed among respiratory alkalosis, respiratory acidosis, and normal acid-base balance.

Treatment of Hypokalemia

Hypokalemia was corrected using potassium salts orally in a quarter of patients and intravenously in 6%, with both being used in one patient. Magnesium deficiency was corrected with intravenous magnesium sulfate. Notably, frusemide was in use among 38% of patients at the time of hypokalemia, perhaps because of hypertension, cardiovascular disease, and/or poor renal function.

Risk Factors for Hypokalemia

The three factors most closely related to the occurrence of hypokalemia were the female sex, the use of diuretics, and corticosteroid therapy. Being female increased the risk by 244%, while diuretics were correlated with a 194% increase. Females are known to have less interchangeable potassium stores in their bodies, especially as they age, which puts them at higher risk for hypokalemia following diuretic use.

Explanations and Implications of Hypokalemia

However, hypokalemia was not associated with either severe disease or death during hospitalization. This may be explained by the mostly mild level of hypokalemia, induced by factors such as reduced intake of food, medication-induced diarrhea, viral injury to the gut, and the use of diuretics and corticosteroids.

Despite the very low incidence of moderate or severe hypokalemia, which can cause cardiac rhythm abnormalities, paralysis, and rhabdomyolysis, the study indicates the need to monitor this group of patients for arrhythmias, especially when drugs like hydroxychloroquine and azithromycin are used off-label to treat COVID-19. These medications are known to reduce the rate of cardiac conduction.

Does COVID-19 by itself cause urinary potassium loss? The viral has been found in urine samples from patients with severe COVID-19 and may possibly cause acute kidney injury, causing abnormal potassium handling. Another explanation is that the renin-angiotensin system is abnormally activated by the loss of ACE2 function in disrupted cells. However, more data on the levels of renin and aldosterone are required to support this hypothesis, despite the findings of metabolic alkalosis and low sodium excretion.

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

Journal references:

Article Revisions

  • Mar 22 2023 - The preprint preliminary research paper that this article was based upon was accepted for publication in a peer-reviewed Scientific Journal. This article was edited accordingly to include a link to the final peer-reviewed paper, now shown in the sources section.
Dr. Liji Thomas

Written by

Dr. Liji Thomas

Dr. Liji Thomas is an OB-GYN, who graduated from the Government Medical College, University of Calicut, Kerala, in 2001. Liji practiced as a full-time consultant in obstetrics/gynecology in a private hospital for a few years following her graduation. She has counseled hundreds of patients facing issues from pregnancy-related problems and infertility, and has been in charge of over 2,000 deliveries, striving always to achieve a normal delivery rather than operative.


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  1. Pippa Blaylock Pippa Blaylock United Kingdom says:

    Good piece on potassium levels. How interesting too. Pure serendipity ... as my extensive blood assay has been completed very regularly since September 2019 to present and so has been monitored throughout the COVID infections. I believe I was exposed to the very first round of COVID in June 2019 having travelled to Seattle and Washington State being my second trip in two years to the USA and if as i believe there has been a long lag phase perhaps even July 2018? Prior to HRT my potassium levels were robust. Questioning medics they knew little how it placed me in terms of risk, for the first variants but initial data suggested loss of testosterone and increasing levels of oestrogen afforded protection. I may have auto immune issues from a long way back and had a sub total thyroidectomy following thryotoxicosis as a teenager. March 2020 finally culminated in going down with COVID and although quite poorly I wasn't hospitalised, I say finally as 'it' appeared to flare every three months since 2018. I had extreme fatigue often. Fast forward to two Pfizer jabs and I experienced a 'reset' in terms of my health it was as if I had been 'wiped clean' finally. Then as my transition became more completed and with one jab I had a 24 hour 'Kent variant' flare as best as I can describe. Then  recently after my second jab I got the same 'nasty summer cold' that BBC reporter Andrew Marr described and felt pretty poorly again and had a blood test around the 19th July and my potassium levels that had been drifting downwards were returned at 2.9 mEq/l 'abnormal' and repeat testing confirmed a slight improvement. Serum potassium level (XE2pz) 3.4 mmol/L [3.5 - 5.3]  I had also experienced hypertension and hypokalaemia and thought best call for emergency advice considering how weak and tired I felt. from an endocrine blood perspective I am ostensibly female now but only had this low potassium effect when I assume i caught the Delta variant and the Pfizer jab did not protect me completely but did better for the Kent variant. I would say I have recovered better than I did during the period prior to my jabs so I didn't get hospitalised but felt it might be heading that way but it was simply acute rather giving longer term fatigue. Hopefully this is the last time this I encounter COVID n !

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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