The effect of dietary supplements on the nPCR in stable hemodialysis patients

Abstract

Objective: To investigate whether (1) dietary supplements raise the normalized protein catabolic rate (nPCR) and/or further improve the nutritional status of stable hemodialysis patients who have both a low nPCR and a low dietary protein intake, <1.2 g/kg body weight/day; and if (2) protein intake measured by nPCR reflects protein intake measured by estimated food diaries in stable patients. Design: Prospective experimental study with a single intervention group. Setting: Hospital outpatient hemodialysis unit. Subjects: Seventeen stable chronic hemodialysis patients (10 men, 7 women) were studied over 8 months. Intervention: Subjects with both a low nPCR and dietary protein intake <1.2 g/kg body weight/day received dietary supplements for the first 2 months. Measurements to assess protein intake and nutritional status were taken at baseline and repeated at the end of 2 months, and at 6 months postintervention. Main outcome measure: nPCR, dietary protein intake using 7-day estimated food diaries, serum urea, serum albumin, serum creatinine, serum bicarbonate, dialysis adequacy ( Kt V ), and body mass index (BMI). Results: Dietary supplements significantly increased both the nPCR and the total protein intake at 2 months (1.21 ± 0.26, 1.10 ± 0.12, respectively) compared with baseline (0.95 ± 0.18, 0.75 ± 0.19, respectively) and 8 months (0.99 ± 0.12, 0.78 ± 0.21, respectively), P < .0001, respectively. There was no change in the nutritional status of the subjects. There was a significant difference between the nPCR and the dietary protein intake at baseline, P < .004; at 2 months, P < .047; and at 8 months, P < .001. Conclusion: Dietary supplements can significantly increase the nPCR and dietary protein intake in stable hemodialysis patients with a low nPCR and dietary protein intake. Because a low nPCR is associated with a high morbidity and mortality rate, it may be prudent to supplement such patients. The use of the nPCR to quantify dietary protein intake in stable hemodialysis patients should be used with caution.