Nutritional effects of KT/V in children on peritoneal dialysis: are there benefits from larger dialysis doses?

Dialysis adequacy is monitored by urea kinetic modeling (UKM), in particular by calculation of KT/V (normalized whole body urea clearance) and PCRN (normalized protein catabolic rate). All children on peritoneal dialysis from our unit (7 children; mean age 7 years, 8 months) participated in our study (dialysis research program of the French Registry of Peritoneal Dialysis). Every month analysis of dialysate and urine collections and blood samples were compared to a 3-day diet survey to analyze the relations between doses of dialysis (KT/V) and nutrition [dietary protein intake (DPI) and caloric intake]. Calculated protein intake and DPI were also compared. Spearman correlation coefficients were used to assess the association between variables. KT/V values were spread over a wide range (0.8-2.8, mean 1.9). KT/V was positively (weakly) correlated to PCRN (p = 0.07, y = 0.24x + 1.08, r = 0.2), but not to DPI. No correlation could be found between PCRN and DPI, but doses of dialysis (KT/V) were positively correlated to caloric intake (p = 0.001, y = 28.97x + 13.66, r = 0.424). We assume that the correlation between KT/V and PCRN is not necessarily the reason, but only a calculation effect. On the contrary, the positive correlation between KT/V and caloric intake allows us to speculate that more efficient dialysis enhances appetite.