Predicting resting energy expenditure (REE): Misapplying equations can lead to clinically significant errors

Abstract

Summary Background & Aims Predicted REE is often the largest component of a nutritional prescription. While inaccuracy due to individual variability is well-known, prediction errors due to mis-applying equations have been largely ignored. Methods Size of error was determined for: A. Mis-quotation of the Harris-Benedict (HB) equation; B. Substitution of the Department of Health (DOH) basal metabolic rate (BMR) equation into REE equations developed from the Harris-Benedict (HB) equation; C. Using the HB equation in children; D. Using ‘general’ rather than disease-specific stress factors; and E. Double-inclusion of dietary-induced thermogenesis (DIT). Dietitians were surveyed to determine whether they could detect large errors. Results Errors were up to: A. 87%; B. 30%; C. 298%; D. 33%; E. 10%. Errors A–D were highly variable and dietitians could not accurately define error size. Conclusions Errors from misapplying equations can pass undetected by dietitians and are large enough to result in major complications if applied to nutritional support. Such errors will apply to new as well as current equations. Avoiding these errors when predicting REE for a range of individuals necessitates a complex array of equations; this may only be practical by using bedside software.