Kidney Week

Abstract: TH-PO0077

Preoperative Serum Potassium in Patients with ESKD

Session Information

• Fluid, Electrolyte, and Acid-Base Disorders: Clinical Research
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Fluid, Electrolytes, and Acid-Base Disorders

• 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical

Authors

• Fielding-Singh, Vikram, Stanford University School of Medicine, Stanford, California, United States

Vikram Fielding-Singh, MD

• Vanneman, Matthew, Stanford University School of Medicine, Stanford, California, United States

Matthew Vanneman, MD

• George, Elizabeth L., Stanford University School of Medicine, Stanford, California, United States

Elizabeth L. George, MD, MSc

• Lin, Eugene, University of Southern California Keck School of Medicine, Los Angeles, California, United States

Eugene Lin, MD, MS, FASN

• Chertow, Glenn M., Stanford University School of Medicine, Stanford, California, United States

Glenn M. Chertow, MD, MPH, FASN

• Gessner, Daniel, Stanford University School of Medicine, Stanford, California, United States

Daniel Gessner, MD

Background

Experts often recommend checking serum potassium concentrations in patients who require chronic dialysis for end-stage kidney disease (ESKD) before surgical procedures to detect hyperkalemia. Others have noted anecdotal experience that hyperkalemia may be relatively well tolerated perioperatively in patients with ESKD.

Methods

We identified adults ≥ 18 years old with ESKD who underwent surgical procedures from January 1, 2018 to December 31, 2025 using Epic Cosmos. We included patients with diagnosis codes for ESKD listed prior to or on the day of a surgical procedure and a mean estimated glomerular filtration rate < 30 mL/min/1.73 m² in the prior year. Patients with evidence of prior kidney transplantation were excluded.
We extracted serum potassium values. We fit a Cox proportional hazards regression model for 30-day mortality with preoperative serum potassium modeled as a 5-knot restricted cubic spline with robust standard errors clustered by health system. We adjusted for demographic, procedural, and comorbidity variables.

Results

We identified 372,989 index surgical procedures in patients with ESKD. Of these, 233,477 (62.6%) had a preoperative serum potassium obtained within 24 hours of the procedure. The mean serum preoperative potassium concentration was 4.4 (standard deviation 0.6) mEq/dL. Hyperkalemia (serum potassium ≥ 5.5 mEq/dL) was observed within 24 hours in 16,502 (4.4%) procedures; hypokalemia (serum potassium ≤ 3.0 mEq/dL) was observed prior to 2,766 (0.7%) procedures. Preoperative hyper- and hypokalemia were both associated with increased risks of postoperative mortality (Figure).

Conclusion

The association between preoperative hyperkalemia and increased risk of postoperative mortality contradicts the claim that patients with ESKD are accustomed to hyperkalemia and demonstrates that perioperative hyperkalemia in this population may have significant clinical consequences.

Funding

• NIDDK Support