Abstract
It seems reasonable to postulate that an observed relationship between dialysis dose and protein intake reflects improved nutrition with correction of uremic symptoms. This article demonstrates a purely statistical association between the two parameters--protein intake, expressed as normalized protein catabolic rate (NPCR), and dialysis dose quantified as KT/V [the product of urea clearance (K) and treatment time (T) divided by the distribution volume of urea (V)] in peritoneal dialysis. The use of random samples from independent normal distributions of K, V, and urea generation rate (G) for the calculation of KT/V and NPCR reveals that a statistical association is introduced when both protein intake and dialysis dose are normalized proportional to a common distribution V. Not the normalizing parameter V per se, but rather the variability of V accounts for the introduction of this statistical artifact.