New equation to estimate resting energy expenditure in non-critically ill patients

Abstract

Background: Correct measurement of resting energy expenditure (REE) is essential to offer a proper nutritional management during hospital stay. Dietitians are not able to perform an effective dietary treatment if predicted REE values are obtained from invalid equations.

Objective: The aim of this study was to develop a more valid method to estimate REE in non-critically ill Portuguese patients.

Design: In this cross-sectional study, REE was measured by indirect calorimetry (IC) in 180 non-critically patients during hospital stay (50 participants were allocated to the validation group by simple randomization and the remaining 130 were allocated to the derivation group). The best accurate equations were derived by multiple linear regression analysis (stepwise) based on anthropometric variables. The equations were tested on the validation group and compared with published predictive equations.

Results: Data was collected from 130 patients, 68 women (52.3%) and 62 men (47.7%), mean age was 58.9 ± 16.8 years and REE-IC was 1918 ± 721 kcal/day. The new best-fit equation REE (kcal/day) = 14.4 (Height) + 52.7 (MUAC) + 453.4 (1 if male, 0 if female) - 371.2 (if Obese) - 2138.3 showed strength of evidence decisive (BF₁₀ = 8008), when compared by Bayesian model, and r² = 0.315. Only estimated REE values obtained using new equations did not present significant difference when compared with measured REE values (kcal/kg).

Conclusions: In this study, new equations derived from a non-critically ill population showed higher validity in estimating REE than currently used equations. A better estimation of REE may lead to a better nutritional intervention and a decreased risk of undernutrition in hospitalized patients.

Keywords: Energy estimation equation; Hospitalized patients; Indirect calorimetry; Non-critical ill patients; Resting energy expenditure.