The correlation between protein catabolic rate and Kt/V in hemodialysis is not a mathematical artifact.

To test whether the demonstrated correlation between Kt/V urea and normalised protein catabolic rate (NPCR) is caused by a mathematical artifact, we examined 12 adult and 8 paediatric haemodialysis patients. Kt/V was determined by the classical method. As an equivalent of NPCR we measured normalised urea generation rate (NUGR) by a one-week collection of dialysate and urine using total body water estimated by bioelectrical impedance for normalisation. The correlation between Kt/V and NUGR was 0.58 (all), 0.55 (adults), and 0.62 (children). Since the determination of Kt/V and NUGR are not interdependent, we conclude that the correlation between Kt/V and protein catabolism is not artifactual.