Abstract: TH-PO516

Effect of Sodium Bicarbonate Treatment on a Novel Marker of Serum Calcification Propensity

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 305 CKD: Clinical Trials and Tubulointerstitial Disorders

Authors

  • Kendrick, Jessica B., University of Colorado Denver and Denver Health Medical Center, Denver, Colorado, United States
  • Andrews, Emily, University of Colorado Denver, Aurora, Colorado, United States
  • Pasch, Andreas, University Hospital Bern, Bern, Switzerland
  • You, Zhiying, UC Denver, Aurora, Colorado, United States
  • Chonchol, Michel, University of Colorado, Aurora, Colorado, United States
Background

Acid retention in patients with chronic kidney disease (CKD) results in increased production of inflammatory markers and activation of the renin-angiotensin-aldosterone system, all of which can induce vascular calcification. We examined the effect of treatment of metabolic acidosis with oral sodium bicarbonate therapy on a novel test that measures the overall calcification propensity of serum, T50, in patients with CKD stage 3-4.

Methods

We performed a prospective, randomized, open-label , 14-week crossover study of 20 patients with CKD stage 3-4 and metabolic acidosis (serum bicarbonate level of ≥ 16 and <22 mEq/L). Subjects were randomly assigned to start with either treatment or control. Each period was 6 weeks in duration with a 2-week washout period in between. Patients were treated with oral sodium bicarbonate tablets for goal bicarbonate of ≥ 22 mEq/L. Serum T50 was measured at the beginning and end of each treatment period. T50 measures the transformation time of amorphous calcium phosphate-containing primary calciprotein particles (CPP) to crystalline hydroxyapatite-containing secondary CPP. A higher T50 represents lower calcification propensity. Mixed effect models were used to examine changes in T50 during treatment and control conditions.

Results

The mean (SD) age and eGFR was 58.5 ± 12.8 years and 24.6 ± 8.1 ml/min/1.73m2, respectively. The mean (SD) serum bicarbonate level and T50 level at baseline was 19.7 ± 2.3 mEq/L and 256.4 ± 56.2 minutes, respectively. Serum bicarbonate levels increased significantly with sodium bicarbonate therapy. There was no significant change in serum T50 during treatment or control conditions. Serum phosphate increased significantly with bicarbonate therapy.

Conclusion

In our study, treatment of metabolic acidosis with oral sodium bicarbonate therapy did not decrease serum calcification propensity in patients with CKD.

 Control

Baseline
Control

6 weeks
P-valueTreatment

Baseline
Treatment

6 weeks
P-valueBetween group
P-value
Bicarbonate (mEq/L)19.7 ± 2.319.6 ± 3.20.9319.3 ± 2.922.0 ± 3.1<0.0010.005
T50 (minutes)
279.9 ± 44.5275.1 ± 33.50.64233.0 ± 57.9225.2 ± 94.30.770.90
Calcium (mg/dL)9.4 ± 0.59.2 ± 0.50.139.2 ± 0.59.3 ± 0.50.390.03
Phosphorus (mg/dL)4.2 ± 0.84.2 ± 1.10.854.1 ± 0.64.5 ± 1.10.020.04

Funding

  • NIDDK Support