Albumin and Amino Acid Levels as Markers of Adequacy in Continuous Ambulatory Peritoneal Dialysis

Abstract

Similar to previous findings in HD patients, a markedly decreased serum albumin level has been found to be a strong predictor of morbidity and mortality in CAPD patients. However, a slight decrease in serum albumin levels (to about 30 g/L if measured with nephelometry or the bromcresol purple method) does not always seem to reflect impaired nutritional status or to be associated with an increased morbidity or mortality in CAPD patients. A low serum albumin level among CAPD patients is related to dialysate albumin loss, comorbidity, age, and a low dietary protein intake. The possible relation between the dialysis dose (as assessed by small solute clearances) and serum albumin levels among CAPD patients is much less established and needs further study, although serum albumin tends to increase in prospective studies of increased peritoneal dialysis dose. Although the plasma levels of amino acids seem to be lower in CAPD patients compared to HD patients, this does not reflect the intracellular amino acid pattern in muscle which is less abnormal in CAPD patients, possibly because of the sustained hyperinsulinemia during CAPD, resulting in an increased intracellular to extracellular gradient. It is at present not established to what extent the amino acid abnormalities are related to the dialysis dose. Malnourished and hypoalbuminemic CAPD patients should be recommended to increase the protein intake, and if this is not effective, the dialysis dose should be increased. Furthermore, the use of amino acid-based peritoneal dialysis solutions is a promising new tool for the treatment of malnourished CAPD patients and may become an important component of CAPD therapy in the future. On the other hand, if the nutritional status deteriorates in spite of these efforts, the patient should be transferred to hemodialysis if possible.