Hyperkalemia Increases Death Risk
Death risk increased markedly once serum potassium values exceeded 5.5 mEq/L.
CHICAGO—Hospitalized patients whose potassium levels rise above 5.5 mEq/L have an increased risk of early death, new findings presented at the American Society of Nephrology's 2016 Kidney Week meeting suggest.
Using electronic medical records for 17,317 patients (average age 50.2) treated 2014 to 2015 at Hennepin County Medical Center, an academic metropolitan safety-net hospital in Minneapolis, David T. Gilbertson, PhD, co-Director of the Chronic Disease Research Group, part of the Minneapolis Medical Research Foundation in Minneapolis, and colleagues analyzed the distribution of serum potassium values and the risk of in-hospital mortality. Of these patients, 35.6% had diabetes, 27.4% had chronic kidney disease (CKD), and 18.6% had congestive heart failure, conditions that have been linked with greater risks of hyperkalemia.
The investigators found a U-shaped relationship between serum potassium levels and in-hospital mortality, with the lowest risks of early death for normal serum potassium levels between 3.5 and 5.0 mEq/L. The death rate rose to above 80% for those with potassium values 7 mEq/L and greater. Although rare, potassium values above 6.0 mEq/L were associated with 43.54 times greater odds of mortality compared with values below 5.0 mEq/L. Hypokalemic patients with potassium values below 3 mEq/L had 12.3% increased death rate. The researchers further observed that variability in potassium values during the hospital stay was associated with greater mortality.
A greater proportion of patients with diabetes, chronic kidney disease, or heart failure had potassium values above 5.0 mEq/L at 5.17%, 4.0%, 7.87%, and 7.48%, respectively.
“It is unclear how much of the observed mortality is directly attributable to hyperkalemia—or hypokalemia—and potentially preventable. It remains possible that high serum potassium values simply are a marker for severe, life-threatening illnesses, such as sepsis, acute myocardial infarction, and trauma,” Dr Gilbertson told Renal & Urology News. “More intense efforts targeted to prevent severe hyperkalemia in patients with diabetes, CKD, and heart failure may be warranted.”
1. Gilbertson DT, Wetmore JB, St. Peter WL, and Herzog CA. Association of Potassium Values with Mortality: Data from a Metropolitan Safety-Net Hospital. Presented at: Kidney Week 2016. November 15-20, 2016. Chicago. Abstract 474.