Table 3.

Multivariable analysis model for 28-day mortality in the development set

Characteristics	Multivariable analysis			Bootstrapping method
	HR	95% confidence interval	p value	Relative frequency*
Lung cancer	2.025	1.345–3.050	0.001	0.959
Vital signs at ED admission
Respiratory rate ≥ 22/min	2.517	1.713–3.698	< 0.001	0.858
Body temperature < 38.0 °C	2.918	1.903–4.475	< 0.001	0.994
Altered mentation	2.021	1.328–3.074	0.001	0.923
Laboratory values
Albumin < 2.8 g/dL	2.473	1.665–3.672	< 0.001	0.977
Lactic acid, mmol/L			< 0.001
4.0–7.9	1.597	1.032–2.473	0.04	0.997
≥ 8.0	3.767	2.343–6.054	< 0.001

HR hazard ratio

*A 50% relative frequency of selection in bootstrap resampling was the criterion for inclusion of predictors in the final multivariate model