One discussion this week included serum potassium levels in the setting of chronic kidney disease (CKD).

Reference: Montford JR, Linas S. How dangerous is hyperkalemia? Journal of the American Society of Nephrology. 2017 Nov; 28(11):3155-3165. doi: 10.1681/ASN.2016121344

Summary: A recent review article by Montford and Linas (2017) summarizes the clinical data linking hyperkalemia with poor outcomes and discusses how the efficacy of certain treatments might depend on the clinical presentation. Below are some points from the section on CKD.

One of the first studies to demonstrate an independent association of hyperkalemia and risk of subsequent death involved a large retrospective study of Japanese patients with advanced CKD presenting for dialysis initiation. An initial serum potassium level >5.5 meq/L at dialysis vintage was the strongest single independent predictor of mortality after an average of 15 years of follow-up. In patients on hemodialysis, potassium levels >5.6 and >5.7 meq/L have been associated with higher mortality. This is also reflected in patients on peritoneal dialysis, with one study suggesting hyperkalemia >5.5 meq/L is associated with a heightened risk of death. Potassium increases during longer intradialytic intervals, and many have attempted to link these fluctuations to the higher incidence of sudden cardiac death in patients with ESRD.

A recently published retrospective observational trial of 52,734 patients on a Monday/Wednesday/Friday hemodialysis schedule revealed that serum potassium levels 5.5–6.0 meq/L were associated with higher risk for subsequent hospitalization, emergency department visits, and mortality within 4 days of measurement.