Phosphate clearance in peritoneal dialysis: automated PD compared with continuous ambulatory PD

Although dialytic removal of phosphate significantly contributes to the management of phosphate levels in end-stage renal disease, many patients on peritoneal dialysis (PD) still do not reach optimal phosphate control. The present review discusses the impact of PD modality--continuous ambulatory (CAPD) or automated (APD)--on phosphate removal. Relevant factors are the diffusive properties of the phosphate anion and the kinetics of phosphate distribution in various body compartments. Confounders that potentially affect comparisons of phosphate clearances in CAPD and APD are differences in residual renal function, membrane transport status, and prescribed dialysis dose. The evidence reviewed here is not strong enough to clearly determine if one modality has a clear advantage with respect to phosphate removal. In the absence of final proof the data suggest that, given the same residual renal function and dialysis dose, CAPD might be slightly more effective than APD at peritoneal phosphate clearance, especially in low transporters.