Table 3.

Quartiles of baseline angiopoietin-2 and von Willebrand factor and ventilator-free days in patients with acute lung injury

Baseline Biomarker Level	Mean Change in Ventilator-Free Days (95% Confidence Interval)	p
Angiopoietin-2 (infection-related acute lung injury)
First quartile	Referent	N/A
Second quartile	−2.2 (−4.6 to 0.16)	.07
Third quartile	−2.5 (−4.8 to −0.1)	.04
Fourth quartile	−4.1 (−6.3 to −1.8)	<.001
Test for trend across quartiles	—	.006
Angiopoietin-2 (noninfection-related acute lung injury)
First quartile	Referent	N/A
Second quartile	−2.4 (−5.4 to 0.7)	.13
Third quartile	−7.1 (−10.3 to −3.9)	<.001
Fourth quartile	−5.7 (−9.6 to −1.8)	.004
Test for trend across quartiles	—	.0001
von Willebrand factor
First quartile	Referent	N/A
Second quartile	−0.5 (−2.4 to 1.4)	.59
Third quartile	−1.9 (−3.8 to −0.03)	.046
Fourth quartile	−4.6 (−6.5 to −2.7)	<.001
Test for trend across quartiles	—	<.0001

N/A, not applicable.