Table 3.

Sensitivity Analyses of Multivariable Logistic Regression of Factors Associated with Late Intensive Care Use

	Late intensive care use (47 cases)				Late intensive care use excluding cases without mechanical ventilation use (29 cases)
	Model 1*		Model 2†		Model 3
Variables	Odds ratio (95% CI)	P value	Odds ratio (95% CI)	P value	Odds ratio (95% CI)	P value
Age, months‡		0.06		0.08		<0.001
<6	2.05 (0.96–4.37)		2.03 (0.91–4.51)		5.64 (2.52–12.64)
≥6	Reference		Reference		Reference
Female	1.13 (0.70–1.83)	0.61	1.09 (0.66–1.80)	0.74	1.05 (0.49–2.24)	0.91
Birth weight, pounds
<5	2.33 (1.31–4.16)	0.004	2.22 (1.30–3.78)	0.003	2.46 (1.25–4.87)	0.009
≥5	Reference		Reference		Reference
Exposed to tobacco smoke	1.47 (0.83–2.60)	0.19	-	-	-	-
When difficulty breathing began prior to index visit
<24 hours or no difficulty breathing	-	-	Reference		-	-
1–3 days	-	-	0.88 (0.29–2.66)	0.82	-	-
≥4 days	-	-	0.41 (0.14–1.19)	0.10	-	-
Highest respiratory rate first day of admission
<70	Reference		Reference		Reference
≥70	4.67 (2.84–7.69)	<0.001	4.72 (2.88–7.74)	<0.001	3.19 (1.72–5.94)	<0.001
RSV/HRV status
RSV only	Reference	-	-	-	-
HRV only	0.52 (0.12–2.35)	0.40	-	-	-
Others§ or none	1.06 (0.62–1.83)	0.82	-	-	-

Abbreviations: CI, confidence interval; RSV, respiratory syncytial virus; HRV, human rhinovirus.

^*Adding exposure to tobacco smoke to the original model.

^†Adding duration of difficulty breathing and removing the virus pathogens from the original model.

^‡Variables were dichotomized in the multivariable model.

^§Others includes adenovirus, human metapneumovirus, and co-infections.