Resting energy expenditure and its determinants in hemodialysis patients

Objective: Chronic kidney disease is associated with several metabolic disturbances that can affect energy metabolism. As resting energy expenditure (REE) is scarcely investigated in patients on hemodialysis (HD) therapy, we aimed to evaluate the REE and its determinants in HD patients. Design: Cross-sectional study. Setting: Dialysis Unit of the Nephrology Division, Federal University of Sao Paulo, Brazil. Subjects: The study included 55 patients ( 28 male, 41.4 +/- 12.6 years old) undergoing HD therapy thrice weekly for at least 2 months, and 55 healthy individuals pair matched for age and gender. Subjects underwent fasting blood tests, as well as nutritional assessment, and the REE was assessed by indirect calorimetry. Results: REE of HD patients was similar to that of pair-matched controls (1379 +/- 7272 and 1440 +/- 7259 kcal/day, respectively), even when adjusted for fat-free mass (P = 0.24). REE of HD patients correlated positively with fat-free mass (r = 0.74; P < 0.001) and body mass index (r = 0.37; P < 0.01), and negatively with dialysis adequacy (r = -0.46; P < 0.001). No significant univariate correlation was found between REE and age, dialysis vintage, serum creatinine, urea, albumin, bicarbonate, parathyroid hormone (PTH) or high-sensitivity C-reactive protein (CRP). In the multiple linear regression analysis, using REE as dependent variable, the final model showed that besides the well-recognized determinants of REE such as fat-free mass and age, PTH and CRP were the independent determinants of REE in HD patients (R-2 = 0.64). Conclusions: In this study, the REE of HD patients was similar to that of healthy individuals, even with the positive effect of secondary hyperparathyroidism and inflammation on REE of these patients.