What is the mortality rate associated with severe hyperkalemia?

Updated: Apr 09, 2020
  • Author: Eleanor Lederer, MD, FASN; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Complications of hyperkalemia range from mild ECG changes to cardiac arrest. Weakness is common as well. The primary cause of morbidity and mortality is potassium’s effect on cardiac function. [55] The mortality can be as high as 67% if severe hyperkalemia is not treated rapidly. [56]

In hospitalized patients, hyperkalemia is an independent risk factor for death. In one series, 406 (1.4%) of 29,063 patients who were hospitalized developed hyperkalemia; 58 (14.3%) of the 406 died, with the risk increasing as the potassium level increased. [53]

Whereas 28% of patients with a serum potassium level above 7 mEq/L died, only 9% of those with a potassium level below 6.5 mEq/L died. [53] In 7 of the 58 deaths, the cause of death was directly attributable to hyperkalemia. Most cases resulting in death were complicated by renal failure. It is noteworthy that all of the patients who died of hyperkalemia had normal potassium levels within the 36 hours preceding death.

Interestingly, in a large study of individuals living in the community, serum potassium leveles greater than 5.0 mEq/L correlated with increased mortality, although the mechanisms were not clear. [57]

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