ABSTRACT
Decline in residual renal function in CAPD patients often leads to reduced overall solute clearances. Inadequate dialysis has been linked to malnutrition and increased morbidity and mortality rates. Achieving dialysis adequacy targets is often difficult by the conventional method of increasing CAPD exchange volumes. In comparison, substantial increases in solute clearances can be achieved with the use of automated peritoneal dialysis with large fill volumes and an extra daytime exchange.
Subject(s)
Kidney Failure, Chronic/therapy , Peritoneal Dialysis, Continuous Ambulatory/methods , Peritoneal Dialysis/methods , Adult , Aged , Blood Urea Nitrogen , Creatinine/blood , Dialysis Solutions/administration & dosage , Female , Humans , Kidney Failure, Chronic/metabolism , Kidney Failure, Chronic/psychology , Male , Middle Aged , Nutritional Status , Peritoneal Dialysis/adverse effects , Peritoneal Dialysis/psychology , Peritoneal Dialysis, Continuous Ambulatory/adverse effects , Peritoneal Dialysis, Continuous Ambulatory/psychology , Quality of Life , Treatment OutcomeABSTRACT
Abnormalities of energy metabolism may exacerbate the high prevalence of protein-calorie malnutrition and inadequate calorie intake in continuous ambulatory peritoneal dialysis (CAPD) patients, leading to further nutritional depletion. In a controlled study, using indirect calorimetry, we evaluated oxygen consumption (VO2), CO2 production, resting energy expenditure, and respiratory exchange ratio (RER) in 12 CAPD patients at rest and during a standard CAPD exchange and in 11 healthy nonuremic control patients. In addition, we investigated the influence of nutritional status and dialysis adequacy on energy metabolism in the CAPD group. There was no significant difference in resting energy parameters between the two groups. Unlike the control group, blood glucose and RER were maintained during prolonged fasting in the CAPD patients. This observation indicates that all the absorbed glucose was used as a metabolic fuel preventing fat oxidation. There was no significant relationship between energy expenditure and dialysis adequacy. There was no significant relationship between nutritional state (including energy intake) and energy expenditure despite evidence of malnutrition in 41% of the patients. If maintenance of "normal levels" of energy expenditure occurs in dialysis patients with suboptimal calorie intake (especially with evidence of protein-calorie malnutrition), this inability to conserve energy may act as an additional risk factor for ongoing malnutrition.
Subject(s)
Energy Metabolism , Peritoneal Dialysis, Continuous Ambulatory , Aged , Anthropometry , Basal Metabolism , Blood Glucose/analysis , Body Composition , Calorimetry, Indirect , Energy Intake , Female , Humans , Male , Middle Aged , Nutritional Status , Oxygen Consumption , RespirationABSTRACT
For both hemodialysis and CAPD patients nutrition has been linked to mortality. Protein calorie malnutrition is present in 20 to 40% of CAPD patients. The normalized protein catabolic rate (NPCR), has been proposed as a useful measure of dietary protein intake and ultimately nutrition. However, the NPCR value has not been consistently predictive of outcome in CAPD patients. We have performed a cross sectional study on 147 clinically stable CAPD patients, who had a mean dialysis duration 22 months, to evaluate the relationship between the NPCR and conventional markers of nutrition. The NPCR was significantly correlated with normalized models of dialysis adequacy including KT/V (urea), total weekly creatinine clearance and the dialysis index. A significant negative correlation was found between individual anthropometric measures and the NPCR. Using a composite nutritional index to nutritionally categorize our population we found a significantly higher NPCR value in the severely malnourished group. The unadjusted protein catabolic rate (PCR) was significantly correlated with individual nutritional measures and was significantly greater in the well-nourished group. The NPCR, obtained by dividing the PCR by body weight (itself a nutritional measure), is lowest in well-nourished or obese patients, and thus as a marker of nutrition may be flawed. The PCR has nutritional relevance, however, adjusting its value to take into account patient size will require prospective evaluation of the influence of small solute removal on body composition.
