Resting metabolic rate (RMR) is an important parameter to guide nutritional therapy of class III obese patients. The objective of the present study was to compare indirect calorimetry (IC) with other predictive equations. This is a cross-sectional study on women with class III obesity (body mass index > 40 kg/m²). Weight, height, fat-free mass, fat mass and resting metabolic rate of all individuals were measured. Bland-Altman plot was used to analyze the agreement between IC and predictive equations` results. A total of 101 women with obesity class III, mean age of 36.3±10 years were evaluated. Harrys-Benedict and WHO equations showed similar bias and limits, (181.6 kcal, +2SD=765.5, -2SD=-402.2), (156.4 kcal, +2SD= 799.4, -2SD= -486.6, respectively). The Mifflin-St. Jeor and Owen equations showed large clinical bias (mean of 239.2 kcal and 463.9 kcal, respectively), and a tendency to overestimate RMR. The prediction equations tested in the study had low accuracy in estimating RMR of women with class III obesity.
Acknowledgements: Grant#2015/06624-1, São Paulo Research Foundation (FAPESP)