Kidney Week

Abstract: FR-PO881

Association of Pre-ESRD Serum Bicarbonate with Post-ESRD Mortality among Incident Dialysis Patients: A Transition of Care in CKD Study

Session Information

• Dialysis: Epidemiology, Outcomes, Clinical Trials - Non-Cardiovascular - II
  November 03, 2017 | Location: Hall H, Morial Convention Center
  Abstract Time: 10:00 AM - 10:00 AM

Category: Dialysis

• 607 Dialysis: Epidemiology, Outcomes, Clinical Trials - Non-Cardiovascular

Authors

• Obi, Yoshitsugu, UC Irvine, Orange, California, United States

Yoshitsugu Obi,

• Catabay, Christina J., UC Irvine, Orange, California, United States

Christina J. Catabay,

• Soohoo, Melissa, UC Irvine, Orange, California, United States

Melissa Soohoo,

• Park, Christina, UC Irvine, Orange, California, United States

Christina Park,

• Streja, Elani, UC Irvine, Orange, California, United States

Elani Streja,

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

Csaba P. Kovesdy,

• Kalantar-Zadeh, Kamyar, UC Irvine, Orange, California, United States

Kamyar Kalantar-Zadeh,

Background

Serum bicarbonate (S-CO₂) levels decline as CKD progresses and rise after dialysis initiation. While the current clinical guidelines suggest maintaining S-CO₂ > 22 mEq/L among pre-ESRD patients with CKD, there are scarce data on the impact of pre-ESRD S-CO₂ levels on post-ESRD mortality.

Methods

Among 32,655 US veterans who transitioned to dialysis between October 2007 and March 2014, we calculated 6-month averaged levels and annual decline rate of S-CO₂ during the last pre-ESRD period, and then estimated their risk for all-cause mortality with Cox regression adjusting for demographics, comorbidities, BMI, and eGFR.

Results

Mean baseline concentrations and rates of decline of S-CO₂ were 23±4 mEq/L and -1.8±2.4 mEq/L/year, respectively. Higher S-CO₂ >20 mEq/L showed higher adjusted mortality risk while there was no clear trend in the lower range. Compared to S-CO₂ of 22 mEq/L, adjusted HRs (95%CIs) were 0.96 (0.94–0.97), 1.09 (1.07–1.12), and 1.22 (1.18–1.27) at 20, 24, and 26 mEq/L, respectively. Consistent associations were observed irrespective of sodium bicarbonate use. There was a U-shaped association between the rate of decline in S-CO₂ and mortality with the lowest risk being approximately -2.0 mEq/L/year. Both faster decline and rise in S-CO₂ were more strongly associated with mortality among sodium bicarbonate users vs. non-users.

Conclusion

Pre-ESRD S-CO₂ levels above 20 mEq/L exhibited an incrementaly higher post-ESRD mortality risk. Further studies are needed to elucidate whether high S-CO2 is a surrogate of low protein intake, comorbid states, or other mechanisms.

Funding

• NIDDK Support