Comparison of the accuracy of resting energy expenditure assessment using bioimpedance analysis and indirect respiratory calorimetry in children with simple obesity

Background: Assessment of resting energy expenditure (REE) is necessary for the formation of a diet for obesity patients. The «gold standard» for assessment of resting energy expenditure (REE) is indirect respiratory calorimetry. Currently, bioimpedance analyzers are increasingly being used in clinical practice to assess energy consumption at rest, including in obese children. However, the accuracy of such an assessment remains unclear. Aims: To determine the accuracy of the assessment of resting energy expenditure using bioimpedance analysis in children with simple obesity compared with indirect respiratory calorimetry. Materials and methods: Resting energy expenditure was assessed by bioimpedance analysis, Harris-Benedict formula and indirect respiratory calorimetry in all obese children. Comparability of methods was assessed using the Bland-Altman analysis. Results: The study included 320 children aged 7 to 17 years with simple obesity.Resting energy expenditure assessed by bioimpedance analysis was on average 232 kcal lower than the actual. A significant CI (-448 to 912 kcal) was revealed, as well as a large LOA from -514 to 979 kcal. REE calculated by the Harris-Benedict formula on average corresponded to the actual one, and CI varied from -38 to 27 kcal. However, large LOA from -514 to 979 kcal, indicating a high individual variability of resting energy consumption. Conclusions: Bioimpedance analyzers underestimate REE in obese children compared to indirect respiratory calorimetry and the Harris-Benedict formula. Given the significant discrepancies in the accuracy of REE assessment, bioimpedance analysis cannot be considered as an alternative to indirect respiratory calorimetry to assess resting energy in children with simple obesity.