Increased resting energy expenditure compared to predictive theoretical equations in Amyotrophic Lateral Sclerosis

Abstract Introduction About 50-60% of Amyotrophic Lateral Sclerosis (ALS) is characterized by an increase of metabolic rate. Harris and Benedict's (HB) 1919 formula is the equation mainly used to calculate REE (cREE) compared to measured REE (mREE) by indirect calorimetry (IC), but others are also applied in current practice. The present study aimed i) to assess mREE in ALS patients compared to 12 cREE formulas and ii) to study the relevant threshold of REE variation to screen patients with the higher evolving risk. Method Nutritional assessments and body composition (by bioimpedance analysis) were performed in ALS patients. mREE was measured by IC and cREE was calculated using HB 1919 and 1984, World Schofield, De Lorenzo, Johnstone, Mifflin, WHO/FAO, Owen, Fleisch, Wang, Rosenbaum and Nelson formulas. Functional and Respiratory evolution and survival by Log-rank test according to two thresholds of REE variation 10% and 20% were studied. Results 315 ALS patients were included. Median mREE was 1503 kcal/24h (1290 – 1698) and was higher than all predictive equations (p Conclusion The increase of metabolic rate is present according to the different cREE formulas used compared to IC. In clinical practice REE formulas, such as HB 1919, HB 1984 or Mifflin, can be used as a reference value compared to IC to screen ALS patients with REE variation over 20% who have a higher evolving risk.