Table 4.

Multivariate logistic regression analysis for the primary outcome of 28-day mortality

Variables	Odds ratio	95% CI	P value
Age (decade effect)	1.51	1.17–1.93	0.001
Female	1.08	0.58–2.01	0.81
Charlson Comorbidity Index	1.09	0.99–1.21	0.09
SpO2/FiO2 ≤ 214	8.19	1.02–65.7	0.05
SpO2/FiO2 > 214<357	2.11	0.27–16.9	0.48
<7.7 mL/kg PBW	2.05	0.85–4.97	0.11
≥7.7–9.2 mL/kg PBW	1.45	0.57–3.67	0.43
≥9.2–11.0 mL/kg PBW	0.83	0.31–2.27	0.72

CI indicates confidence interval; FiO₂, fraction of inspired oxygen; PBW, predicted body weight; SpO₂, oxygen saturation by pulse oximetry.