Activity-related energy expenditure of patients undergoing hemodialysis

Objectives: The aim of this study was to evaluate the activity-related energy expenditure (AEE) of patients undergoing hemodialysis (HD) and to compare it with that of healthy controls.

Design: This was a cross-sectional study.

Setting: This was an in-center study conducted at the Dialysis Unit, Nephrology Division, Federal University of São Paulo-Oswaldo Ramos Foundation, Brazil.

Patients and methods: AEE was evaluated in 32 patients undergoing HD (20 men, aged: 46.3 ± 12.2 years). A subgroup consisting of 22 patients was pair-matched by gender and age with 22 sedentary, healthy individuals. AEE was measured over a period of 5 days using a portable physical activity monitor. Body fat and lean body mass were assessed by dual energy X-ray absorptiometry and body cell mass by bioelectrical impedance analysis.

Results: AEE correlated positively with lean body mass and body cell mass, and negatively with age, body fat, and body mass index. From the multiple regression analysis, it was found that age and lean body mass (r(2) = 0.32) or body cell mass (r(2) = 0.30) were the best among the variables that explained variations in AEE. AEE of HD patients in comparison with healthy controls was found to be lower on dialysis days (234 [9.5 to 1,145] kcal/day vs. 565 [214 to 1,319] kcal/day, median [range]; P < .01) as well as on nondialysis days (369 [89.5 to 1,242] kcal/day vs. 565 [214 to 1,319] kcal/day; P = .02). Total energy expenditure of the HD patients on dialysis days (2,051 ± 289 kcal/day) as well as nondialysis days (2,202 ± 283 kcal/day) was also found to be lower in comparison with controls (2,514 ± 307 kcal/day; P < .01). The average contribution of the AEE toward total energy expenditure in HD patients was 15%, whereas in controls it was 24% (P = .03).

Conclusion: As compared with sedentary, healthy individuals, AEE was reported to be considerably lower in HD patients.