Reduced residual renal function is associated with endothelial dysfunction in patients receiving peritoneal dialysis

Background: Endothelial dysfunction, which contributes to atherosclerosis and arteriosclerosis, commonly accompanies end-stage renal disease (ESRD). However, little is known about the role of residual renal function (RRF) in endothelial protection in ESRD patients. This study aimed to investigate the relationship between endothelial function and RRF in patients undergoing peritoneal dialysis (PD). Methods: This was a cross-sectional study involving 72 prevalent PD patients. Demographic and clinical data were recorded and residual glomerular filtration rate (GFR), Kt/V urea, and serum concentrations of inflammatory markers were measured. Endothelial function was assessed by brachial artery endothelium-dependent vasodilation [flow-mediated dilation (FMD)] to reactive hyperemia following 5 minutes of forearm ischemia. Results: In patients with FMD% above the median value (FMD > 2.41%), residual GFR was significantly higher compared to that in patients with FMD% below the median [1.50 (0 - 9.64) vs 0.48 (0 - 3.89) mL/min/1.73 m ², P = 0.026]. Correlation analyses revealed that residual GFR (p = 0.381, P = 0.001) and total Kt/V urea (y= 0.408, P < 0.001) were positively correlated with FMD%, whereas PD duration (y = -0.351, P = 0.003), high-sensitivity C-reactive protein (p = -0.345, P = 0.003), pulse pressure (y = -0.341, P = 0.003), and age (y = -0.403, P < 0.001) were inversely correlated with FMD%. In contrast, there was no correlation between peritoneal Kt/V urea and FMD%. In multivariate linear regression analysis adjusted for these factors, residual GFR was found to be an independent determinant of FMD% ((3 = 0.317, P = 0.017). Conclusion: This study shows that RRF is independently associated with endothelial dysfunction in ESRD patients on PD, suggesting that RRF may contribute to endothelial protection in these patients.