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Kidney Week

Abstract: FR-PO299

Serum Bicarbonate Levels Are Not Associated with Total Kidney Volume in Patients with Polycystic Kidney Disease

Session Information

Category: CKD (Non-Dialysis)

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

Authors

  • Ramirez-Renteria, Lorena, University of Colorado School of Medicine, Aurora, Colorado, United States
  • You, Zhiying, UC Denver, Aurora, Colorado, United States
  • Gitomer, Berenice Y., Div. Renal Diseases and Hypertension,, Aurora, Colorado, United States
  • Chonchol, Michel, University of Colorado , Aurora, Colorado, United States
  • Kendrick, Jessica B., University of Colorado School of Medicine, Aurora, Colorado, United States
Background

Enhanced ammoniagenesis has been proposed as a potential mechanism of kidney cystic disease progression in patients with polycystic kidney disease (PKD). Animal studies have found that administration of sodium bicarbonate slows cyst enlargement and prevents development of interstitial inflammation and chronic fibrosis. We tested the hypothesis that higher serum bicarbonate levels in patients with PKD are associated with lower total kidney volume (TKV).

Methods

We included 383 patients from the HALT-PKD Study A with baseline serum bicarbonate levels and at least two measurements of TKV. Bicarbonate was examined as a continuous variable and in categories (≤ 24, 25-28 and >28 mEq/L, with 25-28 mEq/L as the reference group). Total kidney volume was measured using imaging from a 1.5T MRI scanner. The outcome was yearly change in slope of TKV. Linear regression models were used to examin the association between serum bicarbonate and change in TKV.

Results

The mean (SD) age was 37.4 (8.0) years. The mean (SD) serum bicarbonate and estimated glomerular filtration rate at baseline was 27.0 (2.4) and 90.0 (17.0) ml/min/1.73m,2 respectively. Participants with lower serum bicarbonate ≤ 24 mEq/L were more likely to be younger, female and to have higher systolic blood pressure than those with a serum bicarbonate > 28 mEq/L. There was no association between serum bicarbonate and change in annual slope of TKV when serum bicarbonate was examined as a continuous variable or in categories (Table 1).

Conclusion

Serum bicarbonate levels are not associated with total kidney volume in patients with PKD.

Annual Change in Slope of TKV (β Estimate (95% CI))
Serum bicarbonate (mEq/L)UnadjustedModel 1Model 2
Per 1 mEq/L increase3.6 (-0.9 to 8.1)0.3 (-4.0 to 4.6)1.1 (-3.1 to 5.4)
<25
25-28
>28
-15.4 (-47.5 to 16.7)
REF
9.6 (-15.2 to 34.5)
-7.7 (-37.7 to 22.4)
REF
-3.3 (-26.9 to 20.4)
-8.9 (-46.1 to 20.4)
REF
0.5 (-22.7 to 23.7)

Model 1: adjusted for age, gender, race Model 2: adjusted for model 1 plus smoking, cardiac history, BMI, SBP, baseline eGFR and urine albumin to creatinine ratio

Funding

  • Other NIH Support