Table 3. Cox proportional hazard regression analysis for 30-day mortality.

Characteristics	Univariate		Multivariate
	HR (95% C.I.)	P value	HR (95% C.I.)	P value
Age, per 1 year increment	1.011 (0.994–1.029)	0.22	1.011 (0.989–1.035)	0.32
Sex
Female	1 [Reference]		1 [Reference]
Male	1.071 (0.614–1.868)	0.81	0.900 (0.496–1.635)	0.73
Cerebrovascular disease
No	1 [Reference]		1 [Reference]
Yes	2.29 (1.12–4.679)	0.02	2.115 (0.916–4.885)	0.08
APACHE II, per 1 increment	1.064 (1.031–1.099)	<0.01	1.029 (0.990–1.071)	0.15
P/F ratio, per 1 increment	0.996 (0.992–0.999)	0.03	0.996 (0.992–1.000)	0.07
Hemodialysis
No	1 [Reference]		1 [Reference]
Yes	2.224 (1.255–3.941)	<0.01	1.519 (0.721–2.670)	0.24
Use of vasopressors
No	1 [Reference]		1 [Reference]
Yes	2.247 (1.268–3.981)	0.01	1.388 (0.721–2.670)	0.33
Cumulative day 1–4 fluid balance, per 1 liter increment	1.169 (1.088–1.256)	<0.01	1.095 (1.012–1.186)	0.03

HR: hazard ratio; C.I.: confidence interval; APACHE: acute physiology and chronic health evaluation; P/F ratio: PaO2/FiO2 ratio.