Phosphate clearance in peritoneal dialysis

Abstract

In renal failure, hyperphosphatemia is common and correlates with increased mortality making phosphate removal a key priority for dialysis therapy. We investigated phosphate clearance, removal and serum level, and factors associated with phosphate control in patients undergoing continuous ambulatory (CAPD), continuous cyclic (CCPD) and automated (APD) peritoneal dialysis (PD). In 154 prevalent PD patients (mean age 53.2 ± 17.6 year, 59% men, 47% anuric), 196 daily collections of urine and 368 collections of dialysate were evaluated in terms of renal, peritoneal and total (renal plus peritoneal) phosphorus removal (g/week), phosphate and creatinine clearances (L/week) and urea KT/V. Dialytic removal of phosphorus was lower in APD (1.34 ± 0.62 g/week) than in CAPD (1.89 ± 0.73 g/week) and CCPD (1.91 ± 0.63 g/week) patients; concomitantly, serum phosphorus was higher in APD than in CAPD (5.55 ± 1.61 vs. 4.84 ± 1.23 mg/dL; p < 0.05). Peritoneal and total phosphate clearances correlated with peritoneal (rho = 0.93) and total (rho = 0.85) creatinine clearances (p < 0.001) but less with peritoneal and total urea KT/V (rho = 0.60 and rho = 0.65, respectively, p < 0.001). Phosphate removal, clearance and serum levels differed between PD modalities. CAPD was associated with higher peritoneal removal and lower serum level of phosphate than APD.

Urine volume as an estimator of residual renal clearance and urinary removal of solutes in patients undergoing peritoneal dialysis

“…This study extends our analyses reported previously with detailed clarification of urine volume importance as an estimate of solute removal 13 , 14 .…”

“…Besides the classical markers of kidney function and dialysis adequacy, urea and creatinine, the impact of residual kidney function on phosphate metabolism is of recent interest in PD 13 – 17 and hemodialysis 18 , 19 .…”

Influence of dietary protein on serum phosphorous levels in peritoneal dialysis patients with different initial transport function

“…These results indicated that, early on, urinary and peritoneal phosphorus clearances were complementary during PD. For patients with better residual renal function, urinary phosphorus clearance plays an important role in regulating the phosphorus balance, particularly in patients with slower peritoneal transport function ( Table 6 ); Thus, retaining residual renal function is essential for serum phosphorus control [ 20 , 21 ].…”

Phosphate balance during dialysis and after kidney transplantation in patients with chronic kidney disease

“…In a study of 67 patients on peritoneal dialysis, reduced residual renal function was associated with higher levels of FGF-23, which was shown to be a more stable marker of phosphate metabolism than is phosphate or PTH [50]. A cross-sectional study involving 154 peritoneal dialysis patients showed that phosphate removal was greater in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) than in those undergoing continuous cyclic peritoneal dialysis (CCPD) or automated peritoneal dialysis [51]. The authors found that higher dialysate volume was associated with higher phosphate removal, and that there was a significant correlation between peritoneal phosphate and creatinine clearances, even when patients with and without anuria were analysed separately.…”