Underreporting of energy intake in peritoneal dialysis patients

This study aimed to assess the prevalence of underreporting among patients treated by peritoneal dialysis (PD), and to investigate whether the reported energy intake is influenced by overweight status in this population.

This was a prospective, observational study.

This study took place at the Dialysis Unit of the Nephrology Division, Federal University of São Paulo-Oswaldo Ramos Foundation, São Paulo, Brazil.

Forty adult patients were recruited: 24 men and 16 women; age, 53.4+/-16.5 years; body mass index (BMI), 25.1+/-3.8 kg/m(2) (x+/-SD); median duration of dialysis, 19 months (range, 3 to 101 months). Only patients on PD >3 months, free of peritonitis for at least 3 months, without catabolic conditions and with normal thyroid function, were included.

Energy intake was evaluated using a 3-day food record. Resting energy expenditure (REE) was measured by indirect calorimetry. Body composition was assessed using dual-energy x-ray absorptiometry. The total energy (TE) offered was considered the sum of energy intake plus energy provided by glucose absorption. All measurements were collected at baseline and after 6 months. Underreporting of energy intake was considered to have occurred when the TE/REE ratio was <1.40.

The TE/REE ratio was 1.35+/-0.31. Twenty-one patients (52.5%) had a TE/REE ratio <1.40. The TE/REE ratio correlated negatively with BMI (r=-0.52, P < .01), and positively with duration of dialysis (r=0.44, P < .01). No correlation was found between TE/REE ratio and any other variables. Patients were divided into two groups according to BMI <25 kg/m(2) and BMI > or =25 kg/m(2). The majority of patients (83.3%) in the higher BMI group had a TE/REE ratio <1.40. In a logistic regression analysis, using TE/REE ratio <1.40 or > or =1.40 as the dependent variable, BMI> or =25 kg/m2 was the only determinant of energy underreporting. After 6 months of follow-up, no change in either body weight or BMI was evident.

This study showed that a significant number of PD patients underreported the energy intake evaluated by 3-day food diaries. This finding was evidenced particularly in overweight patients.