Kidney Week

Abstract: TH-PO0393

Effect of Sodium Bicarbonate on Serum Calciprotein Particles in CKD

Session Information

• Fluid, Electrolyte, and Acid-Base Disorders: Clinical - 1
  November 06, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Fluid, Electrolytes, and Acid-Base Disorders

• 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical

Authors

• Eiwaz, Mahaba B, Albert Einstein College of Medicine, New York, New York, United States

Mahaba B Eiwaz

• Koike, Seiji, Oregon Health & Science University, Portland, Oregon, United States

Seiji Koike, MS

• Graham, Garry Anthony, Albert Einstein College of Medicine, New York, New York, United States

Garry Anthony Graham

• Dobre, Mirela A., Case Western Reserve University, Cleveland, Ohio, United States

Mirela A. Dobre, MD, MPH, FASN

• Lapidus, Jodi A., Oregon Health & Science University, Portland, Oregon, United States

Jodi A. Lapidus, PhD

• Abramowitz, Matthew K., Albert Einstein College of Medicine, New York, New York, United States

Matthew K. Abramowitz, MD, MS, FASN

• Hostetter, Thomas H., The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States

Thomas H. Hostetter, MD

• Cheung, Alfred K., University of Utah Health, Salt Lake City, Utah, United States

Alfred K. Cheung, MD

• Raphael, Kalani L., University of Utah Health, Salt Lake City, Utah, United States

Kalani L. Raphael, MD, MS, FASN

• Melamed, Michal L., NYU Langone Health, New York, New York, United States

Michal L. Melamed, MD

• Chen, Wei, Albert Einstein College of Medicine, New York, New York, United States

Wei Chen, MD, MS, FASN

Background

Animal studies suggest that sodium bicarbonate may worsen vascular calcification. A faster transformation (i.e., low T₅₀) from primary to secondary calciprotein particles (CPP2) and/or larger CPP2 suggest a reduced mineral buffering capacity in blood and is associated with mortality. Here, we tested the hypothesis that sodium bicarbonate reduces T₅₀ and increases CPP2 size in blood.

Methods

We performed post hoc analyses of two published double-blind, placebo-controlled trials of oral sodium bicarbonate therapy in CKD: the VA-Bicarb Trial (n=74) and Alkali Therapy in CKD Trial (n=149). Participants with normal serum bicarbonate levels were randomized to receive either sodium bicarbonate 0.4-0.5 mEq/kg/day or placebo. In the stored serum samples obtained from baseline, month 3 and month 6, we measured T₅₀ using nephelometry and CPP2 size using dynamic light scattering. Linear mixed effect models were used to test the effects of sodium bicarbonate on the changes in T₅₀ and CPP2 size in each trial and pooled data.

Results

In VA Bicarb Trial, eGFR was 52±18mL/min/1.73m² at baseline; T₅₀ was 154 ± 44 min. There was no significant change in T₅₀ with sodium bicarbonate therapy (Figure). In Alkali Therapy in CKD Trial, eGFR was 36±11mL/min/1.73m² at baseline; T₅₀ was 131 ± 36 min. At month 3, the mean T₅₀ was 14 minutes higher (95% CI, 1-26, p=0.03) in bicarbonate treated patients relative to placebo, while there was no significant change in T₅₀ at month 6. In pooled analyses of both trials, the mean T₅₀ was 12 minutes higher (95% CI, 2-22, p=0.02) in the bicarbonate group relative to placebo at month 3, while there was no significant change in T₅₀ at month 6. There was no significant change in CPP2 size in either trial or in pooled analyses.

Conclusion

In people with CKD, T₅₀ increased after 3 months of oral sodium bicarbonate therapy but this effect was not sustained after 6 months. Notably, the effect was primarily observed in the Alkali Therapy in CKD Trial, in which participants had lower eGFR, suggesting that any positive effect may be observed in those with worse kidney function.

Funding

• NIDDK Support

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.20259ybcwned