Resting energy expenditure in adults with nonalcoholic fatty liver disease and type 2 diabetes mellitus: comparison between measured and predicted values.

BACKGROUND: Indirect calorimetry (IC) is the gold standard for determining energy requirements. Resting energy expenditure (REE) equations could noninvasively estimate energy requirements in healthy individuals. Whether the published equations could accurately predict the REE of adults with nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) remains unclear. Here, we aimed to investigate the accuracy of predicted REE in patients with NAFLD and T2DM using different equations. METHODS: REE was measured using IC and compared with ten predictive equations in 88 adult patients aged 30-53 years. The agreement between the measured REE with IC and REE, as predicted by equations, was assessed using the Bland-Altman method. RESULTS: The analysis showed that the FAO/WHO/UNU (version using weight) equation had the smallest average bias (10.2 kcal/d; 95% confidence interval [CI], -57.4 to 78) and the highest accuracy (46.5%); meanwhile, the Thumb equation had the greatest average bias (-402.2 kcal/d; 95% CI, -477.3 to -327.1) and the lowest accuracy (20.4%). The highest values ​​of overestimating and underestimating were related to the Thumb and Owen equations, respectively. The 95% limits of agreement were found to be smaller in the equations by Muller (version using fat-free mass), compared to others. CONCLUSION: The FAO/WHO/UNU (weight) equation, thus, performed the best in predicting energy expenditure when applied to patients with NAFLD and T2DM. However, all the prediction equations provided REE estimates within 10% of the measured ones in less than 50% of the cases.