Correlation between Fractional Reabsorption of Sodium and Erythropoietin dose in Peritoneal Dialysis Patients

Abstract

Background

Erythropoietin (EPO) deficiency of chronic renal failure (CRF) may be a functional consequence of decreased glomerular filtration rate and fractional reabsorption of sodium (FR_Na). Decreased FR_Na reduces renal oxygen consumption and increases tissue oxygen pressure, resulting in less EPO production. We hypothesized that, in CRF patients, there is a positive relationship between EPO production and FR_Na and that, in such patients receiving EPO, a negative correlation is expected between FR_Na and EPO dose.

Methods

Creatinine clearance, FR_Na, serum iron, transferrin, transferrin saturation, ferritin, and intact parathyroid hormone (iPTH) levels were measured in 91 peritoneal dialysis patients. The correlation between EPO dose and FR_Na was studied.

Results

Mean EPO dose was 7076 ± 4821 units/week and mean FR_Na was 93.40% ± 6.14%. A negative correlation was found between EPO dose and FR_Na (r = -0.28, p < 0.01), and a positive correlation was found between both ferritin and iPTH and EPO dose (r = 0.39, p < 0.001 and r = 0.35, p < 0.002 respectively). After adjusting for the effect of creatinine clearance, ferritin, and iPTH, there was still a significant correlation between EPO dose and FR_Na (p < 0.05).

Conclusion

In CRF patients there is a negative correlation between FR_Na and EPO dose, which supports the hypothesis that EPO deficiency may be related to the decreased renal oxygen-consuming work of sodium reabsorption.