Table 2.

Comparison of outcomes according to the three criteria.

	Berlin Definition (253 cases)				Altitude-P/F-corrected criteria (229 cases)				Zhang criteria (204 cases)
	Mild	Moderate	Severe	P values	Mild	Moderate	Severe	P values	ALI	ARDS	P values
No(%)	49(19.37)	148(58.50)	56(22.13)		107(46.72)	84(36.68)	38(16.59)		87(42.65)	117(57.35)
ICU mortality, No(%)	3(6.12)	28(18.92)	24(42.86)	<0.001	19(17.76)	18(21.43)	18(47.37)	0.001	16(18.39)	36(30.77)	0.045
28-day mortality, No(%)	3(6.12)	49(33.11)	34(60.71)	<0.001	25(23.36)	37(44.05)	24(63.16)	<0.001	23(26.44)	60(51.28)	<0.001
No of ventilator-free days over a 28-day period, d, median (IQR)	26.17	18.73	0	<0.001	21.42	16.53	5.6	<0.01	19.5	4.21	0.03
	(20.00–27.21)	(0.00–25.30)	(0.00–18.26)		(3.75–26.50)	(0.00–24.28)	(0.00–16.02)		(0.00–26.04)	(0.00–23.31)
ICU length of stay, d, median (IQR)	6	8.71	6.69	0.024	7.67	8.23	7.69	0.929	8.08	7.79	0.246
	(2.23–12.32)	(4.63–18.10)	(3.53–14.18)		(3.67–14.92)	(3.71–16.96)	(4.30–14.77)		(4.63–16.42)	(3.63–15.17)
Duration of invasive ventilation, d, median (IQR)	1.79	4.75	4.23	0.003	3.88	4.46	5.11	0.132	5.08	4.67	0.945
	(0.73–4.98)	(1.50–10.62)	(2.16–9.92)		(1.04–9.13)	(1.40–9.45)	(2.73–11.85)		(1.46–9.83)	(2.15–10.63)
Hospital length of stay, d, median (IQR)	24	22	16	0.001	23	18.5	18	0.036	23	18	0.059
	(19.00–38.00)	(13.25–35.75)	(6.00–25.75)		(14.00–37.00)	(9.25–30.00)	(8.00–26.00)		(14.00–38.00)	(9.00–29.50)

IQR, Inter Quartile Range.