A comparison of two methods of dietary assessment in peritoneal dialysis patients

Abstract

Objective: To conduct a comparison of two methods of dietary assessment in patients on peritoneal dialysis. Design: Comparative, cross-sectional study of two methods of dietary assessment (3-day diet diary and 24-hour recall). Data was collected simultaneously by a single experienced dietitian. Each assessment was coded and analyzed blind. Setting: Regional speciality peritoneal dialysis training unit. Patients: In this study, 30 peritoneal dialysis patients recruited prospectively and consecutively as they attended for out-patient assessment of dialysis adequacy. Age range was 22 to 77 years. Patients were excluded if unwell, younger than 18 years, or had peritonitis. Outcome measures: Total energy and protein intakes from both methods were compared. Protein intakes from both methods were compared with the protein catabolic rate generated from urea kinetics. Data obtained from both methods were compared using paired t tests, linear regression, and Bland and Altman techniques. Results: There were no significant differences in the mean daily protein (72.4 g v 76.6 g) and total energy (1757 kcals (7.35 MJ) v. 1897 kcals (7.94 MJ)) intakes determined by the two methods. Positive correlations were seen between the measurements for protein intake ( r = .58, P = .0026) energy intake ( r = .78, P < .00001), with mean differences of .066 g/kg/d (SD .38) 2.04 kcal/kg/day (SD 6.67), respectively. For both methods there was a similar positive correlation between dietary protein intake and protein catabolic rate. A 24-hour recall was more likely to result in successful collection of data (29 of 30) than 3-day diet diaries (25 of 30) and was less time consuming. Conclusion: These two methods of determining dietary protein and energy intake do not differ significantly in the information they provide. The relative success in obtaining completed records of intake, the shorter time taken and the opportunity for patient education and assessment of other nutrition related factors has led to the adoption of the 24-hour recall method in our institution.