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Abstract: PO2254

Correlation Between Urinary Sodium and Protein Excretion in CKD

Session Information

Category: CKD (Non-Dialysis)

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

Authors

  • Shaikh, Gulvahid G., Albany Stratton VA Medical Center Albany, Albany, New York, United States
  • Gosmanova, Elvira O., Albany Stratton VA Medical Center Albany, Albany, New York, United States
  • Der Mesropian, Paul J., Albany Stratton VA Medical Center Albany, Albany, New York, United States
Background

Urinary protein excretion often fluctuates in patients with chronic kidney disease (CKD). We aimed to establish a correlation between spot urine sodium (Na) measurement as a surrogate marker of 24hr urine excretion based on Kawasaki formula, and therefore, sodium intake, and urinary protein excretion. We hypothesize that urinary Na excretion may affect urinary protein excretion.

Methods

This was a retrospective study involving 213 US veterans with CKD followed in the Albany VAMC nephrology clinic for the period of 2 years. Patients with cirrhosis, end-stage renal disease, and renal transplant were excluded. Simultaneous measurements of serum Na, Creatinine (Cr) and urine Na, Cr and protein were performed on 2 separate visits. Kawasaki formula was used to estimate 24-hour urine Na excretion. Proteinuria was calculated using urine protein to creatinine ratio (UPCR). Correlations among percent change in estimated 24h urine Na and UPCR were determined with linear regression model.

Results

The mean age ± SD of the cohort was 74.4 ± 9.5 years. Mean estimated GFR was 47.4 ml/min/1.73 m2 and UPCR was 1.0 g/g. About 97% of subjects were male and 51% had diabetes. Using multivariable linear regression, we found that weight, height, BMI, and percent change in estimated 24h urine Na were significant predictors of percent change in UPCR (all p < 0.05). The percent change in UPCR correlated with estimated 24h urine sodium on univariate linear regression (R2 = 0.24, p < 0.01). We found that 68% of cases of UPCR rise also had estimated 24h urine Na increase, while 70% of patients with UPCR fall also had estimated 24h urine Na decrease.

Conclusion

Urine sodium and urine protein excretion correlated in patients with chronic kidney disease. Therefore, the role of dietary sodium as a potential influencing factor of urine protein excretion requires further examination.