Weight loss is one of the strongest predictors of shorter survival in ALS. High calorie diet increases fat mass, and might have survival benefit. Longitudinal study following changes in fat mass is lacking.

A total of 6 ALS patients had 14 DXA scans. Mean age was 57 at enrollment and 5 (83%) were males. The rate of decline in the ALSFRS-R score from disease onset to the second DXA scan was used to group patients. Three patients with fast progression (decline rate of ALSFRS-R score by >1 point/month) died with a mean survival from symptom onset of 21 months (Fast group). All patients used positive pressure ventilation and two had gastrostomy. The other 3 patients had slow progression (decline rate <1 point /month) and survived with a mean disease duration time of 36 months (Slow group). Compared to the Slow group, the Fast group had more weight loss (12.5kg vs 1.2kg, p=0.053), lean mass loss (4.6kg vs 0.7kg, p=0.2) and fat mass loss (7.9kg vs -1.8 kg, p=0.03). One patient in the Fast group had 9.8 kg (42%) fat mass loss while lean mass increased by 0.7kg.

Fat mass change in addition to weight change might serve as a biomarker for disease progression. Additional patient data are being acquired to further evaluate this possibility.