Comparison of measurement by indirect calorimetry of resting energy expenditure, estimation by predictive equations and caloric requirements evaluated by dietetic approach in a cohort of obese patients

Objective. - When the target of loss of weight is difficult to reach, resting energy expenditure (REE) can be used for fixing the proposed level of energy intake. The aim of the study was to prospectively compare in adult obese patients REE measured by indirect calorimetry (REEic) (considered as reference) with REE determined by predictive equations and caloric requirements evaluated by dieticians. Methods. - For each patient, REE was measured by indirect calorimetry and estimated by Harris and Benedict's, WHO's, Mifflin-St Jeor's, Lazzer's and Black's equations and by bioelectrical impedance analysis. The level of caloric requirements was obtained by a dietetic evaluation. REEic was faced with the results of other techniques using Spearman's rank correlation, Wilcoxon's test, and Bland and Altman's method. Results. - Twenty-one patients were included. BMI was 43.9 +/- 6.4 kg/m(2). REEic was significantly correlated with REE obtained by equations (0,65 < R-2 < 0.75 P < 0.0001) or dieticians (R-2 = 0.46, P = 0.0008). There was no significant difference between these methods, except between calorimetry and Black's equation (P = 0.04). Nevertheless, a large dispersion of results was noted (limits of agreement +/- 22.5% to +/- 32.6%), especially when comparing calorimetry and dietetic approach. Conclusions. - In the population explored, predictive equations and dietetic approach are at risk of under-or overestimation not acceptable in clinical practice, underlining the importance of indirect calorimetry for assessing caloric requirements of obese patients. (C) 2011 Societe francaise de nutrition. Published by Elsevier Masson SAS. All rights reserved.