Standard Equations Are Not Accurate in Assessing Resting Energy Expenditure in Patients With Amyotrophic Lateral Sclerosis

Objective: To assess the utility of standard equations for calculating caloric requirements in patients with amyotrophic lateral sclerosis (ALS). Background: Malnutrition substantially increases the risk of death in ALS. Weight loss can be stabilized and survival prolonged with early gastrostomy feeding. However the use of standard nutrition equations has not been validated in this population. We therefore compared measured caloric expenditure to 2 predictive equations in patients with varying stages of ALS. Methods: Thirty-four patients were studied. Caloric expenditure and respiratory quotient (R) were measured using indirect calorimetry. Results were compared with the Harris-Benedict equation. Results: The prediction error for the Harris-Benedict equation was 18.6 + 14.9%. Limits of agreement showed this equation could overestimate caloric expenditure by 591 kcal/d and underestimate requirements by 677 kcal/d. R was >0.86 in 11 patients, suggesting overfeeding, and