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

Introduction: We aimed to assess the association between serum potassium and mortality in patients receiving continuous renal replacement therapy (CRRT). Methods: 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. Results: 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. Conclusion: Hypokalemia and hyperkalemia before CRRT and hyperkalemia during CRRT predicts 90-day mortality.