Trajectory of Serum Potassium in AKI and Mortality Risk

Researchers, led by J. S. Chávez-Iñiguez, MD, conducted a prospective cohort study to examine the association between the trajectory of potassium level and mortality or the need for kidney replacement therapy (KRT) in patients with acute kidney injury (AKI). Results of the study were reported online in Nephron [].

The study cohort included patients with AKI admitted to the Hospital Civil de Guadalajara, Jalisco, Mexico. Patients were categorized into one of eight groups base on the trajectories of serum potassium level during 10 days of hospitalization: (1) normokalemia, defined as serum potassium 3.5 to 5.5 mEq/L; (2) hyperkalemia to normokalemia; (3) hypokalemia to normokalemia; (4) fluctuating potassium; (5) persistent hypokalemia; (6) normokalemia to hypokalemia; (7) normokalemia to hyperkalemia; and (8) persistent hyperkalemia.

The overall cohort included 311 patients with AKI. Mean age was 52.6 years, 58.6% were male, and 63.9% had AKI stage 3. KRT was initiated in 36% of the cohort and 21.2% died.

Following adjustment for confounders, 10-day hospital mortality was significantly higher in groups 7 and 8 (odds ratio [OR], 1.35 and 1.61, respectively; P<.05 for both). Initiation of KRT was higher in group 8 only (OR, 1.38; P<.05).

“In our prospective cohort, most patients with AKI had alterations in serum potassium. Normokalemia to hyperkalemia and persistent hyperkalemia were associated with death, while only persistent hyperkalemia was correlated with the need for KRT,” the authors said.