Nutritional aspects on peritoneal dialysis

Peritoneal dialysis is associated with metabolic and nutritional abnormalities due to the combined effects of uremia per se, glucose absorption from the dialysate and a variety of catabolic factors, such as protein and amino acid losses into the dialysate, poor appetite possibly reflecting insufficient removal of small solutes, and recurrent episodes of peritonitis. Signs of protein-energy malnutrition are common, especially in patients with minimal or no residual renal function. Variables that best correlate with the degree of malnutrition include serum albumin, midarm muscle circumference, clinical signs of muscle wasting and loss of subcutaneous fat, and a history of anorexia. The incidence of malnutrition is higher in females than in males and in diabetics than in non-diabetics. CAPD patients generally have a lower protein intake than HD patients, but may have a lower average protein requirement than HD patients. Progression of malnutrition may occur in CAPD patients due to the synergistic effects of loss of residual renal function, underdialysis, anorexia and inadequate dietary intake. In underdialyzed CAPD patients, the amount of dialysis should be increased and measures should be taken to increase the supply of energy and protein. The use of amino acid-based dialysis fluid may provide new opportunities for compensation of dialytic losses of protein and amino acids, normalization of essential amino acids, supplementation of inadequate dietary protein intake, and improvement of the nutritional status in CAPD patients.