Study of the resting energy expenditure in amyotrophic lateral sclerosis (ALS) patients versus a control population.
Résumé
Introduction: Hypermetabolism (HM) is defined as a variation (Δ) > +10% between the resting energy expenditure (REE) measured and the calculated value. The main objective of the study was to confirm the existence of HM during ALS and to determine its level. Secondary objectives were to specify (i) if REE was increased in patients without HM, and (ii) what was the level of ΔREE compared to healthy subjects.
Methods: A cohort of ALS patients was compared to a control population. The evaluation included anthropometric criteria measurements, REE by indirect calorimetry and body composition by impedancemetry (fat-free mass [FFM], fat mass). Statistical analysis used the Student t, Mann-Withney and Chi2 tests. Multivariate analysis included logistic regression (main objective), and generalized linear models (secondary objectives). The significance threshold was set at <0.05.
Results: 315 patients and 80 controls were compared. 55.2% of patients had HM versus 13.7% of controls (p <0.0001). HM was strongly and positively associated with the presence of ALS (Adjusted Odds Ratio = 9.50 [4.49 -20.10], p <0.0001). The metabolic level was higher in patients (1503 kcal/day [1290-1696] versus 1220 kcal/day [938-1450], p <0.0001), even in the absence of HM (1339 kcal/day [1154-1543] versus 1200 kcal/day [1005-1461], p <0.0001). The ΔREE and the REE/FFM ratio were higher in patients with or without HM. In the absence of HM, the group-effect on ΔREE only concerned subjects older than 67 years old (βadjusted> 0 and p <0.05) and the increase in the REE/FFM ratio only applied to male individuals (Difference in mean REE/FFM ratio between ALS and controls at 1.99 kcal/kg/day [0.22-3.75], p=0.0273).
Conclusion: HM affects more than half of the patients and is associated with ALS. This work confirms a very frequent metabolic deterioration during this disease, even in the absence of HM. The identification of the mechanisms involved could improve patient management.