A new study has linked low levels of normal serum potassium in patients with heart failure to increased risk of death.
The study was conducted by a team of researchers led by Ali Ahmed at the University of Alabama at Birmingham.
As part of the study, researchers studied 1,187 pairs of patients, half with low potassium and half with normal levels, who were balanced in all measured baseline covariates. The patients were enrolled in the Digitalis Investigation Group, a large clinical trial of heart failure patients conducted in 302 centres in the United States and Canada from 1991-1993.
Researchers found that patients with potassium levels less than 4 mEq/L had increased risk of long-term mortality.
"It would appear that the threshold for low potassium, 3.5 mEq/L, needs to be raised for chronic heart failure and that any of these patient with a potassium level less than 4 mEq/L should be considered as having low potassium and thus at increased risk of death," Ahmed said.
"These patients were not significantly more likely to be hospitalized than the higher potassium group, suggesting that most low potassium associated deaths were sudden deaths due to ventricular arrhythmias," he added.
The findings of the study were published in the June issue of the European Heart Journal.