Dietary protein and energy requirements in ESRD patients

The published reports of dietary protein and energy intake and protein and energy requirements for maintenance hemodialysis (MHD) patients and chronic peritoneal dialysis (CPD) patients are reviewed. Evidence indicates that the dietary energy intake of patients undergoing MHD or continuous ambulatory peritoneal dialysis (CAPD) is less than normal. Dietary protein intake in various surveys averages approximately 1.0 g/kg/d. The energy expenditure of MHD patients appears to be normal or slightly increased during resting and normal during various other daily activities. Energy expenditure in CAPD patients appears normal. Nitrogen balance and anthropometric studies in MHD or CAPD patients ingesting controlled diets in a metabolic unit research ward also indicate that dietary energy requirements are normal and are approximately 35 to 38 kcal/kg/d in MHD patients. For CAPD patients, total energy requirements (from diet and dialysate) also appear to be 35 to 38 kcal/kg/d. These recommended energy intakes are for adult patients aged approximately 60 years or younger. Thus, the low dietary energy intakes of MHD and CPD patients are maladaptive. Nitrogen balance studies indicate that a safe dietary allowance for protein is approximately 1.2 g/kg/d for MHD patients and 1.2 to 1.3 g/kg/d for CAPD patients. Because the nutritional status of patients at the onset of chronic dialysis therapy is a strong predictor of both their nutritional status during the course of chronic dialysis treatment and their subsequent morbidity and mortality, it is important to maintain good nutritional status in patients with chronic renal failure before their development of end-stage renal disease (ESRD) and establishment on chronic dialysis. Evidence indicates that there is a reduction in dietary protein and energy intake and a gradual deterioration of nutritional status in patients with chronic renal insufficiency as the glomerular filtration rate (GFR) decreases progressively to less than 50 to 60 mL/min/1.73 m2. More studies are needed to assess dietary protein and energy requirements both for MHD and CPD patients who are clinically stable and for those who have sustained comorbid conditions that increase energy expenditure or protein nitrogen appearance.