TABLE 4.

Prognostic factors associated with survival in multivariable Cox analysis.

	HR	95% CI	p-value
Age of onset, years	1.022	0.978–1.068	0.341
Sex
Female	1.000
Male	0.864	0.343–2.180	0.757
BMI, kg/m2	0.917	0.794–1.059	0.239
Site of onset
Bulbar	1.000
Spinal	0.263	0.091–0.763	0.014
VO2 peak, ml/kg/mina	0.839	0.757–0.930	0.001
HR peak, beats/minb	0.967	0.950–0.985	<0.001
VE/VCO2 slopeb	0.962	0.905–1.024	0.225
VE/VO2 peakb	1.137	1.014–1.274	0.028

The multivariable models included previously established prognostic indicators for ALS and CPET variables (a included the overall CPET parameter reflecting whole-body exercise capacity; b included the three system-specific CPET parameters reflecting cardiovascular, pulmonary, and breathing economy separately).

VO₂, oxygen consumption; HR, heart rate; VE, minute ventilation; VCO₂, carbon dioxide production; BMI, body mass index.