Assessment and Monitoring of Nutrition Status in Pediatric Peritoneal Dialysis Patients

Abnormalities of nutrition status are a common problem in children on peritoneal dialysis (PD) and a source of significant morbidity and mortality. The state of decreased body protein mass and fuel reserves (body protein and fat mass) common in PD patients is now better known as protein–energy wasting (PEW). Protein–energy wasting is a slow, progressive process in chronic kidney disease. The correct approach to this problem includes measurement of early, intermediate, and late markers of PEW, and consideration of the risk factors specific to the patient and to PD. The earliest markers of PEW are associated with some symptoms observed clinically: a decrease in dietary intake and an increase in inflammatory markers. The second stage in the development of PEW (patients with established PEW) is characterized by abnormalities in numerous markers: bioimpedance analysis (BIA) and anthropometric indices, other indices of body mass and composition, biochemical parameters, and indices of protein, glucose, and lipid metabolism. When PEW is established, clear clinical signs become evident: patients in this stage are characterized by high rates of hospitalization and an increased risk for morbidity and mortality as compared with patients without cachexia. Risk factors for PEW can already be present in an apparently well-nourished child who initiates PD: glucose absorption from PD fluid, abdominal distension from PD volume, gastroesophageal reflux, and even more importantly, inadequate dialysis dose in relation to decline in residual renal function. Given the complexity of the pathogenesis and clinical picture of PEW, no single measure, but rather panels of nutritional measures are necessary to diagnose the condition. Combined nutrition scores such as the anthropometry–BIA nutrition score may add value to the monitoring of nutrition status in children on PD.