Kidney Week

Abstract: PUB250

Association of Serum Potassium with Kidney Failure in Patients with CKD

Session Information

• Publication Only

Category: CKD (Non-Dialysis)

• 2202 CKD (Non-Dialysis): Clinical, Outcomes, and Trials

Authors

• Khaliq, Muhammad, The University of Tennessee Health Science Center Department of Medicine, Memphis, Tennessee, United States

Muhammad Khaliq, MD, MBBS

• Jan, Muneeb Ullah, The University of Tennessee Health Science Center Department of Medicine, Memphis, Tennessee, United States

Muneeb Ullah Jan, MD

• Rafaey, Wania, The University of Tennessee Health Science Center Department of Medicine, Memphis, Tennessee, United States

Wania Rafaey, MD, MBBS

• Kovesdy, Csaba P., The University of Tennessee Health Science Center Department of Medicine, Memphis, Tennessee, United States

Csaba P. Kovesdy, MD, FASN

• Hussein, Wael F., The University of Tennessee Health Science Center Department of Medicine, Memphis, Tennessee, United States

Wael F. Hussein, MBBS, MSc, FASN

Background

Serum potassium (SK) abnormalities are common among patients with chronic kidney disease (CKD) and are associated with higher mortality, but the association of SK with CKD progression is less clear. We evaluated the association between SK and end-stage kidney disease (ESKD) in a well characterized longitudinal cohort of patients followed at an outpatient CKD clinic.

Methods

We examined a cohort of 496 patients with eGFR <60 ml/min/1.73 m2 from a single institution, with baseline SK categorized as hypo- (<=3.5), normo- (3.6 – 5.2), and hyperkalemia (>=5.3 mEq/L). The association with ESKD was evaluated using multivariable adjusted cause-specific Cox models. SK was tested both as categorical and continuous variable. Non-linear associations were evaluated using spline analyses. Models were adjusted for demographics, comorbidities, eGFR, proteinuria, and medication use.

Results

Mean age was 65.4 years (SD 15.4), 97.8% were male, and 57.7% had diabetes. Mean eGFR was 35 (SD 11) ml/min/1.73 m2 and 41% were on ACEi/ARB. Hypo-, normo-, and hyperkalemia were present in 6.3%, 89.9%, and 3.8% at baseline respectively.
Over a median follow up of 6.0 years, ESKD incidence rate was 34.3, 19.1, and 55.3 per 1,000 person-years for hypo-, normo-, and hyperkalemia respectively. Compared to normokalemia, the unadjusted ESKD HR was 1.73 (95% CI 0.74 to 4.04) for hypokalemia and 2.46 (95% CI 0.89 to 6.83) for hyperkalemia. Associations remained directionally consistent in the adjusted models. Spline analysis showed a U-shaped association of SK with ESKD, with higher risk at both low and high potassium levels (Figure).

Conclusion

Both hypo- and hyperkalemia are associated with increased risk of ESKD. These findings further support the prognostic importance of SK abnormalities in the non-dialysis CKD population.

Figure: Adjusted spline analysis for the association of serum potassium with ESKD.