(HealthDay News) – Patients hospitalized after an acute myocardial infarction (AMI) with post-admission serum potassium levels between 3.5 and 4.5mEq/L (milliEquivalents per liter) have a lower risk of death than those with higher or lower levels, according to a study published in the January 11 issue of the Journal of the American Medical Association.

Abhinav Goyal, M.D., M.H.S., from the Emory Rollins School of Public Health in Atlanta, and colleagues investigated the relationship between serum potassium levels and in-hospital mortality in patients with AMI. They retrospectively analyzed data from 38,689 patients with biomarker-confirmed AMI, from the Cerner Health Facts database, who were admitted to 67 U.S. hospitals from 2000 through 2008. Patients were categorized by their mean post-admission serum potassium level.

The researchers found a U-shaped relationship between the mean post-admission serum potassium level and in-hospital mortality, which remained after multivariable adjustment. For those with a mean post-admission potassium of 4.0 to <4.5mEq/L, the mortality rate was similar to the reference group, which was a mean of 3.5 to <4mEq/L (5 versus 4.8%, respectively; adjusted odds ratio [aOR], 1.19). For a potassium level of 4.5 to <5mEq/L, the mortality rate was double (10%; aOR, 1.99), and was greater for higher levels of potassium. For potassium levels lower than the reference group (<3.5mEq/L), mortality rates were increased.

“Our data suggest that the optimal range of serum potassium levels in AMI patients may be between 3.5 and 4.5mEq/L,” the authors write.

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