Peritoneal Transport Properties and Dialysis Dose Affect Growth and Nutritional Status in Children on Chronic Peritoneal Dialysis FRANZ SCHAEFER,* GÜNTER KLAUS, OTTO MEHLS,* and THE MID-EUROPEAN PEDIATRIC PERITONEAL DIALYSIS STUDY GROUP

To evaluate a possible effect of peritoneal transport properties and dialysis dose on the physical development of children on chronic peritoneal dialysis, a cohort of 51 children was prospectively followed for 18 mo. Peritoneal transport characteristics were assessed by serial peritoneal equilibration tests (PET), dialysis efficacy by dialysate and residual renal clearance measurements, and growth and nutritional status by the longitudinal changes (D) of height SD score (SDS), body mass index (BMI) SDS, and serum albumin. D height SDS was negatively correlated with the creatinine equilibration rate observed in the initial PET (r 5 20.31, P , 0.05). Multiple regression analysis confirmed the negative effect of the high transporter state (partial r 5 0.07), and disclosed an additional positive effect of dialytic CCr (partial r 2 5 0.11) and a weak negative effect of daily dialysate volume (partial r 5 0.04) on D height SDS. D BMI SDS was strongly age-dependent (r 5 20.48, P , 0.001); while relative body mass gradually increased below 4 yr of age, it remained stable in older children. Positive changes in BMI SDS were associated with rapid PET creatinine equilibration rates (univariate r 5 0.35, P , 0.05) and/or large dialysate volumes (multivariate partial r 5 0.11), suggesting a role of dialytic glucose uptake in the development of obesity. The change in serum albumin concentrations was positively correlated with dialysate volume (partial r 5 0.14), and negatively affected by dialytic protein losses (partial r 5 0.06). In conclusion, the peritoneal transporter state is a weak but significant determinant of growth and body mass gain in children on chronic peritoneal dialysis. Rapid small solute equilibration contributes to impaired growth but enhanced acquisition of body mass. Dialytic small solute clearance has a weak positive effect on statural growth independent of the transporter state, but does not affect body mass gain. In adult patients on chronic peritoneal dialysis (CPD), evidence is increasing that treatment outcome is strongly associated with the efficacy of blood purification (1–7). The daily clearances of creatinine and urea are inversely related to morbidity and mortality rates, and evidence-based guidelines for target clearances of these markers in CPD patients have recently been outlined (8). Moreover, the peritoneal membrane transport properties independently affect outcome in adult CPD patients (9–11). PD prescriptions in children are still largely empirical, and mainly aimed at optimizing daily ultrafiltration and limiting blood urea nitrogen levels to a range that precludes overt signs of uremic toxicity. Peritoneal transport capacity assessments and regular clearance measurements are performed only in a small minority of pediatric dialysis centers. Reasons for the limited interest in efficacy questions in pediatric PD are the generally low morbidity and mortality rates and the relatively short average dialysis periods of children. These factors, together with the small patient numbers in each pediatric dialysis center, render an assessment of PD adequacy in children difficult. Nonetheless, we believe that important possible end points of treatment outcome can be examined in children, which include statural growth, nutritional parameters, and physical and cognitive performance. In an attempt to evaluate possible effects of individual peritoneal transport properties and delivered PD clearances on the course of growth and nutritional indices, we prospectively followed, in a multicenter effort, 51 children who remained on CPD treatment for 18 mo. The patients were continuously monitored with respect to their anthropometric development, peritoneal transport characteristics, delivered dialysis clearances, and residual renal function. Materials and Methods Patients Between June 1993 and January 1997, 213 children and adolescents with end-stage renal failure on CPD in 16 Mid-European pediatric dialysis centers were enrolled in a prospective study designed to evaluate possible relationships between peritoneal transport characteristics, residual and dialysis clearances, and treatment outcome as judged by the evolution of growth and nutritional parameters. Of the 213 original patients, 42 late pubertal adolescents were excluded from Received September 21, 1998. Accepted February 16, 1999. See Appendix for participating investigators and affiliated organizations. Correspondence to Dr. Franz Schaefer, Division of Pediatric Nephrology, University Children’s Hospital, Im Neuenheimer Feld 150, 69120 Heidelberg, Germany. Phone: 149 6221 56 2396; Fax: 149 6221 56 4203; E-mail: [email protected]