Association of serum potassium derangements with mortality among patients requiring continuous renal replacement therapy.

Abstract

We aimed to assess the association between serum potassium and mortality in patients receiving continuous renal replacement therapy (CRRT). We studied 1279 acute kidney injury patients receiving CRRT in a tertiary referral hospital in the United States. We used logistic regression to assess the association of serum potassium before CRRT and mean serum potassium during CRRT with 90-day mortality after CRRT initiation, using serum potassium 4.0-4.4 mmol/L as reference group. Before CRRT, there was a U-shaped association between serum potassium and 90-day mortality. There was a significant increase in mortality when serum potassium before CRRT was ≤3.4 and ≥4.5 mmol/L. During CRRT, progressively increased mortality was noted when mean serum potassium was ≥4.5 mmol/L. The odds ratio of 90-day mortality was significantly higher when mean serum potassium was ≥4.5 mmol/L. Hypokalemia and hyperkalemia before CRRT and hyperkalemia during CRRT predicts 90-day mortality.