title: Models to assess nitrogen losses in pediatric patients on chronic peritoneal dialysis.
abstract: To develop models to estimate nitrogen (N) losses of children on chronic peritoneal dialysis (CPD) from easily measurable indexes and laboratory tests, we measured the N content and all nitrogenous compounds in dialysate (D), urine (U), and feces over 3 days in 19 pediatric patients on CPD. Total measured N losses (TNm) were 5.56+/-2.26 g/day (69.9+/-11.1% in dialysate, 16.3+/-10.6% in urine, and 13.6+/-4.6% in feces). Correlation coefficients between measured dialysate and urinary N losses and the single nitrogenous compounds indicated values of over 0.9 only for urea in dialysate and urine; fecal N losses correlated well with body surface area (BSA). Taking into account these correlations, we developed a univariate additive model and three multivariate models to predict total estimated N losses (TNe). The best prediction of TNm was obtained with model 3, which considered not only urea output in dialysate and urine but also dialysate protein loss and BSA: TNe (g/day)=0.03+/-1.138 UN urea+0.99 DN urea+1.18 BSA+0.965 DN protein. A confirmatory analysis performed on a second group of 23 pediatric patients on CPD, using all four models, showed a higher percentage of studies with a relative difference between TNm and TNe less than 10% for model 3 than for the other models. Thus, N losses of pediatric patients on CPD can be estimated from measured urea and protein losses in dialysate and urea loss in urine, together with BSA.
authors.affiliation: Clinica Pediatrica De Marchi, Milan, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Edefonti
authors.forename: M
authors.initials: M
authors.lastname: Picca
authors.forename: B
authors.initials: B
authors.lastname: Damiani
authors.forename: S
authors.initials: S
authors.lastname: Loi
authors.forename: G
authors.initials: G
authors.lastname: Consalvo
authors.forename: M
authors.initials: M
authors.lastname: Giani
authors.forename: L
authors.initials: L
authors.lastname: Ghio
authors.forename: G
authors.initials: G
authors.lastname: Origgi
authors.forename: M
authors.initials: M
authors.lastname: Ferrario
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001830:Body Surface Area; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000378:metabolism; D005243:Feces / Q000737:chemistry; D006801:Humans; D008954:Models, Biological; D009584:Nitrogen / Q000378:metabolism* / Q000652:urine; D010530:Peritoneal Dialysis / Q000009:adverse effects*; D010531:Peritoneal Dialysis, Continuous Ambulatory; D015203:Reproducibility of Results
chemical_list: D003404:Creatinine; D009584:Nitrogen