Nutritional requirements and actual dietary intake of continuous ambulatory peritoneal dialysis patients.

OBJECTIVE: Nutritional status is related to morbidity and mortality in the continuous ambulatory peritoneal dialysis (CAPD) population. In the present study, we compared the dietary intake of CAPD patients with their requirements for calorie and protein nutrition and with the recommended intakes of potassium and phosphate. DESIGN: Patients were recruited from the CAPD clinic. Desirable body weight was derived from the height of the individual patients and the desirable body mass index (BMI) for adult Asians. The calorie requirement was calculated by multiplying desirable body weight by 30 kcal. The protein requirement was calculated by multiplying desirable body weight by 1.2 - 1.5, according to serum albumin level. The K requirement was set at 3500 mg daily, and the PO(4) requirement, at 1000 mg daily. The actual dietary intake of individual patients was estimated from dietary history by a computer software program. RESULTS: The study included 57 patients who had been on CAPD for 22.1 +/- 23.5 months. Of the 57 patients, 8 patients (14.0%) were below the desirable BMI range, 20 (35.1%) were within the range, and 29 (50.9%) were above the range. By subjective global assessment (SGA), 45 patients (78.9%) were mildly-to-moderately malnourished, and 12 (21.1%) well nourished. Serum albumin was 32.1 +/- 4.7 g/L. Patients met 98% +/- 35.7% (range: 33% - 224%) of their nutritional requirement for calories and 92.1% +/- 37.7% (range: 22% - 202%) of their nutritional requirement for protein. Only 23 patients (40.4%) reached the target for calorie intake, and only 22 (38.6%) reached the target for protein intake. Excess K intake was seen in 1 patient (1.8%), and excess PO(4) intake, in 6 patients (10.5%). Actual dietary intake was not related to BMI or SGA score. CONCLUSION: Most CAPD patients had inadequate calorie and protein intakes. Calorie and protein intakes were not related to BMI and SGA scores. Compliance with recommended K and PO(4) intakes was good.

Nutritional assessment of continuous ambulatory peritoneal dialysis patients by bioelectrical impedance.

OBJECTIVE: The Dialysis Outcomes Quality Initiative (DOQI) guidelines suggest that anthropometric measurements are useful in assessment of nutrition. However, the technique is operator-dependent and time consuming. To estimate fat-free mass and fat mass, bioelectrical impedance analysis (BIA) measures the impedance of an electrical current passing through the body. Our aim in the present study was to validate the use of BIA in continuous ambulatory peritoneal dialysis (CAPD) patients. DESIGN: We recruited patients from the CAPD clinic. The biceps, triceps, subscapular, and suprailiac skinfold thickness were measured by Harpenden skinfold calipers (British Indicators, Burgess Hill, West Sussex, U.K.). Using a linear regression equation (Durin and Womersley) and the Siri equation, we calculated percentage body fat composition from the anthropometric measurements. For BIA assessment, fat composition was measured using the Body Composition Analyzer (TBF-300GS: Tanita Corporation of America, Arlington Heights, IL, U.S.A.). RESULTS: We recruited a total of 60 patients who had been on CAPD for 21.8 +/- 23 months. The percentage of body fat in the study group as estimated by anthropometry was 27.5% +/- 8.6% (range: 5.78% - 40.4%). By BIA, the percentage of body fat was 17.6% +/- 8.9% (range: 2.4% - 42.3%). The results by the two methods were highly correlated (r = 0.712, p < 0.001). By paired t-test, the mean difference in body fat composition using the two different methods was 9.9% +/- 6.6% (p < 0.001). CONCLUSIONS: Measurement of body fat composition in CAPD patients by BIA and by anthropometry were highly correlated. The body fat composition measured by BIA was lower than that measured by anthropometry. The BIA method is simple and noninvasive. It may play a role in monitoring trend of body composition in CAPD patients in an outpatient setting.