Table 1 Baseline characteristics in the original cohort

Age

66.81 ± 16.05

65.01 ± 15.69

68.54 ± 16.20

t=-15.59

< 0.001

Gender, n(%)

χ²=118.68

< 0.001

 F

8204 (41.44)

3652 (37.56)

4552 (45.19)

 M

11,592 (58.56)

6071 (62.44)

5521 (54.81)

Race, n(%)

χ²=36.34

< 0.001

Black

1485 (8.56)

638 (7.74)

847 (9.31)

Other

2471 (14.25)

1294 (15.70)

1177 (12.94)

White

13,384 (77.19)

6312 (76.56)

7072 (77.75)

Weigh

83.69 ± 23.94

85.61 ± 23.69

81.82 ± 24.03

t = 11.12

< 0.001

Laboratory Tests

 WBC (× 10⁹/L)

13.33 ± 10.24

13.60 ± 10.78

13.06 ± 9.68

t = 3.67

< 0.001

 Platelet (× 10¹²/L)

196.37 ± 104.20

188.55 ± 95.76

203.96 ± 111.27

t=-10.42

< 0.001

 Hemoglobin (× 10⁹/L)

10.52 ± 1.89

10.57 ± 1.82

10.48 ± 1.95

t = 3.19

0.001

 PH

7.37 ± 0.07

7.36 ± 0.07

7.37 ± 0.07

t=-8.60

< 0.001

 pCO2 (mmHg)

41.74 ± 9.34

41.56 ± 8.35

41.98 ± 10.50

t=-2.71

0.007

 pO2 (mmHg)

151.20 ± 83.55

174.63 ± 81.31

120.14 ± 76.02

t = 43.99

< 0.001

 PO₂/FiO₂

363.79 ± 256.12

411.82 ± 259.32

275.31 ± 224.70

t = 33.24

< 0.001

 Lactate l (mmol/L)

2.32 ± 1.78

2.48 ± 2.01

2.14 ± 1.44

t = 12.52

< 0.001

 Ureanitrogen (mg/dL)

27.45 ± 21.37

25.06 ± 19.80

29.76 ± 22.55

t=-15.55

< 0.001

 Creatinine(mg/dL)

1.46 ± 1.42

1.34 ± 1.22

1.58 ± 1.57

t=-11.85

< 0.001

 eGFR

74.47 ± 46.04

79.33 ± 47.10

69.77 ± 44.49

t = 14.65

< 0.001

Vital Signs

 MAP (mmHg)

80.47 ± 612.21

85.31 ± 908.87

76.47 ± 51.70

t = 0.95

0.344

 Respiratory rate (bpm)

24.19 ± 644.61

28.30 ± 919.90

20.21 ± 4.29

t = 0.88

0.378

 Spo2(%)

99.82 ± 301.94

99.26 ± 164.73

100.35 ± 391.12

t=-0.25

0.799

 Temperature (°C)

36.84 ± 1.89

36.83 ± 2.59

36.85 ± 1.04

t=-0.87

0.386

Disease Severity Score

 GCS

15.00 (13.00, 15.00)

15.00 (14.00, 15.00)

14.00 (13.00, 15.00)

Z=-14.84

< 0.001

 SAPS II score

38.00 (31.00, 48.00)

40.00 (32.00, 51.00)

37.00 (29.00, 46.00)

Z=-20.32

< 0.001

 SOFA score

5.00 (3.00, 8.00)

6.00 (4.00, 9.00)

5.00 (3.00, 7.00)

Z=-24.01

< 0.001

Comorbidities

 HF

χ²=162.54

< 0.001

  No

14,127 (71.36)

7344 (75.53)

6783 (67.34)

  Yes

5669 (28.64)

2379 (24.47)

3290 (32.66)

 MT

χ²=68.55

< 0.001

  No

16,601 (83.86)

8368 (86.06)

8233 (81.73)

  Yes

3195 (16.14)

1355 (13.94)

1840 (18.27)

 CKD

χ²=104.12

< 0.001

  No

16,277 (82.22)

8269 (85.05)

8008 (79.50)

  Yes

3519 (17.78)

1454 (14.95)

2065 (20.50)

 AKF

χ²=230.45

< 0.001

  No

12,331 (62.29)

6574 (67.61)

5757 (57.15)

  Yes

7465 (37.71)

3149 (32.39)

4316 (42.85)

 Stroke

χ²=3.33

0.068

  No

17,994 (90.90)

8801 (90.52)

9193 (91.26)

  Yes

1802 (9.10)

922 (9.48)

880 (8.74)

 COPD

χ²=43.60

< 0.001

  No

18,289 (92.39)

9106 (93.65)

9183 (91.16)

  Yes

1507 (7.61)

617 (6.35)

890 (8.84)

 Respiratory failure, n (%)

χ²=144.99

< 0.001

  No

12,325 (62.26)

5643 (58.04)

6682 (66.34)

  Yes

7471 (37.74)

4080 (41.96)

3391 (33.66)

 Hypoxemia, n (%)

χ²=18.38

< 0.001

  No

17,458 (88.19)

8672 (89.19)

8786 (87.22)

  Yes

2338 (11.81)

1051 (10.81)

1287 (12.78)

 Hypercapnia, n (%)

χ²=0.87

0.352

  No

19,280 (97.39)

9480 (97.50)

9800 (97.29)

  Yes

516 (2.61)

243 (2.50)

273 (2.71)

 Lactic acidosis, n (%)

χ²=0.83

0.361

  No

15,986 (80.75)

7877 (81.01)

8109 (80.50)

  Yes

3810 (19.25)

1846 (18.99)

1964 (19.50)