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Kidney Week

Abstract: FR-PO634

A Comparison of the Effect of Sodium Bicarbonate on Acid-Base Indices in CKD Patients with and Without Diabetes: A Secondary Analysis of the BASE Pilot Trial

Session Information

Category: Fluid and Electrolytes

  • 902 Fluid and Electrolytes: Clinical

Authors

  • Raphael, Kalani L., University of Utah, Salt Lake City, Utah, United States
  • Larive, Brett, Cleveland Clinic, Cleveland, Ohio, United States
  • Isakova, Tamara, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
  • Ix, Joachim H., UCSD, San Diego, California, United States
  • Wolf, Myles, Duke University, Durham, North Carolina, United States
  • Raj, Dominic S., GWU Medical Faculty Associates, Washington, District of Columbia, United States
  • Mendley, Susan R., NIDDK/NIH, Bethesda, Maryland, United States
  • Fried, Linda F., VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, United States
  • Kendrick, Cynthia A., Cleveland Clinic, Cleveland, Ohio, United States
  • Gassman, Jennifer J., Cleveland Clinic, Cleveland, Ohio, United States
  • Cheung, Alfred K., University of Utah, Salt Lake City, Utah, United States

Group or Team Name

  • The CKD Pilot Studies Consortium
Background

In CKD, those with diabetes mellitus (DM) tend to have higher urinary NH4+ (u-NH4+) excretion, lower urinary pH (u-pH), and in some studies, higher serum total CO2 (s-tCO2) than those without DM at the same level of eGFR. The comparative effect of NaHCO3 supplementation on acid-base indices in those with and without DM is uncertain.

Methods

This was a secondary analysis from the Bicarbonate Administration to Stabilize eGFR (BASE) Pilot Trial, which was a randomized, double-blinded, placebo-controlled study to determine the safety and tolerability of two doses of NaHCO3 in 194 CKD patients over 28 weeks. 90 participants received higher dose NaHCO3 (0.8 meq/kg-lean/d), 52 received lower dose NaHCO3 (0.5 meq/kg-lean/d; n=52), and 52 received placebo. The BASE Pilot Trial found that both doses were safe and well tolerated (Kidney Week 2018, SA-OR036). In this study, we compared the mean change in u-NH4+ excretion, u-pH, and s-tCO2 from baseline between the treatment groups, stratified by DM status, using linear mixed models adjusted for demographics, eGFR, ACR, diuretic use, ACE/ARB use, protein intake, and clinical center.

Results

Mean±SD age was 67±12 years and eGFR was 36±9 ml/min/1.73m2; 54% had diabetes. In DM vs. non-DM, baseline s-tCO2 was 24±2 vs. 24±3 meq/L (p=0.95); u-NH4+ was 22±14 vs. 20±10 meq/d (p=0.19), and u-pH was 5.7±0.5 vs 5.9±0.5 (p=0.03). The lower dose reduced u-NH4+ excretion and increased u-pH similarly in non-DM and DM (Table). With the higher dose, additional effects on u-NH4+ excretion and u-pH were more robust in non-DM, however the interaction p-values were not significant. In both DM and non-DM, statistically significant increases in s-tCO2 were only observed in those treated with the higher NaHCO3 dose.

Conclusion

In individuals with CKD, NaHCO3 may have an attenuated dose-response effect on urinary acid excretion in DM. However, the effect of NaHCO3 on s-tCO2 seems to be similar for those with and without DM, and only the higher dose significantly increased s-tCO2

MeasurementUrinary NH4+ (% change)Urinary pHSerum total CO2 (meq/L)
ComparisonNon-DMDMp-
interaction
Non-DMDMp-
interaction
Non-DMDMp-
interaction
Lower dose vs. placebo-28%
(-48% to 0%)
-39%
(-57% to -15%)
0.470.5
(0.1 to 0.8)
0.5
(0.2 to 0.9)
0.77-0.3
(-1.5 to 0.9)
0.6
(-0.7 to 1.9)
0.31
Higher dose vs. placebo-56%
(-68% to -40%)
-46%
(-60% to -27%)
0.340.9
(0.6 to 1.2)
0.6
(0.3 to 0.9)
0.271.2
(0.1 to 2.4)
1.6
(0.5 to 2.8)
0.64
Higher dose vs. Lower dose-40%
(-56% to -17%)
-11%
(-33% to 19%)
0.070.4
(0.1 to 0.7)
0.1
(-0.2 to 0.4)
0.141.5
(0.3 to 2.8)
1.0
(-0.1 to 2.1)
0.54

Funding

  • NIDDK Support