Kidney Week

Abstract: SA-PO876

Plasma Potassium Trajectories and Associated Post-Transition Mortality in Patients with Advanced CKD Transitioning to ESRD

Session Information

• CKD: Pharmacoepidemiology
  November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2101 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

• Dashputre, Ankur A., University of Tennessee Health Science Center, Memphis, Tennessee, United States

Ankur A. Dashputre,

• Sumida, Keiichi, University of Tennessee Health Science Center, Memphis, Tennessee, United States

Keiichi Sumida,

• Potukuchi, Praveen Kumar, University of Tennessee Health Science Center, Memphis, Tennessee, United States

Praveen Kumar Potukuchi,

• Kar, Suryatapa, University of Tennessee Health Science Center, Memphis, Tennessee, United States

Suryatapa Kar,

• Obi, Yoshitsugu, University of California Irvine, Irvine, California, United States

Yoshitsugu Obi,

• Thomas, Fridtjof, University of Tennessee Health Science Center, Memphis, Tennessee, United States

Fridtjof Thomas,

• Molnar, Miklos Zsolt, University of Tennessee Health Science Center, Memphis, Tennessee, United States

Miklos Zsolt Molnar,

• Streja, Elani, Harold Simmons Center for Kidney Disease Research and Epidemiology, Orange, California, United States

Elani Streja,

• Kalantar-Zadeh, Kamyar, University of California Irvine, School of Medicine, Orange, California, United States

Kamyar Kalantar-Zadeh,

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

Csaba P. Kovesdy,

Background

Potassium (K⁺) homeostasis is impacted by reduced kidney function, but the pre-ESRD trajectory of plasma K⁺ concentration and the associated post-ESRD mortality is unknown.

Methods

In 34,167 US Veterans who transitioned to dialysis between 2007-2014 and had ≥1 K⁺ measurement in each year over the last three years prior to dialysis initiation, we examined K⁺ trajectory (slope) for both the entire three-year and for each of the three one-year pre-ESRD periods, using linear mixed effects models adjusted for fixed (age, sex, race, diabetes and congestive heart failure) and time-varying (RAAS inhibitor, sodium-polystyrene sulphonate, loop diuretics and mineralocorticoid receptor antagonist use, and eGFR) covariates with patient as the random effect. Quadratic spline and Cox regression models were used to assess the multivariable adjusted association between K⁺ slope and all-cause mortality within 6 months of dialysis initiation.

Results

The mean (SD) age of the cohort was 67 (11) years; 98% were male, 29% were African American, and 77% were diabetic. The unadjusted mean (95% CI) K⁺ slope was 0.008 (0.006, 0.011) mEq/l/year, which reversed after multivariable adjustment, especially for eGFR levels (adjusted mean [95% CI] K⁺ slope, -0.10 [-0.13, -0.07] mEq/l/year). Most of the change over time in plasma K⁺ was observed in the last year prior to dialysis. A reverse J-shaped association was observed between K⁺ slope and mortality (Figure).

Conclusion

The average intraindividual plasma K⁺ trajectory is remarkably stable in patients nearing ESRD, likely as a result of physiologic mechanisms and therapeutic interventions which counteract the progressively limited ability of the failing kidneys to excrete K⁺. A declining slope, but not an increasing slope, is associated with higher mortality risk.

Funding

• NIDDK Support