[Comparison of Harris Benedict and Mifflin-St Jeor equations and indirect calorimetry for assessing resting energy expenditure]

ABSTRACT

An understanding of resting energy expenditure [REE] in hospitalized patients is essential for determining their daily energy needs, which can be measured or estimated by equations. Estimation is by far the more common method. This cross-sectional study investigated the degree of agreement between the resting energy expenditure as measured by indirect calorimetry and that predicted by the Harris Benedict and Mifflin-St Jeor equations. In 60 randomly selected patients, aged 18 and 83 years; REE was measured by fitmate indirect calorimetry [Cosmed Company, Rome, Italy] and compared with values predicted using Harris Benedict and Mifflin-St Jeor equations. Statistical analysis was done using the method of Bland-Altman, one-sample t-test and Pearson's correlation. There were no significant differences between mean REEs measured by indirect calorimetry [1311.66 +/- 373.98 kcal/day] and mean REE values predicted by Mifflin-St Jeor [1303.11 +/- 230.94 kcal/day] or Harris Benedict [1339.36 +/- 223.48 kcal/day] equations. However, at an individual level the limits of agreements between the measured values and those predicted by both equations were quite wide [Mifflin-St Jeor 792.83 to 775.73 kilocalorie/day, Harris Benedict 714.58 to 769.98 kilocalorie/day]. At a group level, Harris-Benedict and Mifflin-St Jeor equations are suitable for predicting REE of hospitalized patients. However, the results suggest that for an individual the limits of agreement are very wide in both equations and clinically important differences in REE would be obtained