Table 2 Comparison of clinical characteristics between three AEP groups stratified by the BAL/blood eosinophil score (n = 244)

Number of patients

244

78

108

58

–

Sex (male) (n,%)

243 (99.6)

78 (100)

108 (100)

57 (98.3)

0.200

Mean age (SD)

20.4 ± 1.5

20.3 ± 1.1

20.5 ± 1.9

20.5 ± 1.2

0.488

Smoking history

0.077

 Ever smoker

243 (99.6)

78 (100)

108 (100)

57 (98.3)

 Never smoker

1 (0.4)

0 (0)

0 (0)

1 (1.7)

Cigarette smoking days

26.9 ± 26.9

29.4 ± 34.1

24.8 ± 24.4

27.4 ± 20.3

0.545

WBC

14,231 ± 3888

16,248 ± 5005

14,489 ± 5130

11,037 ± 3888

< 0.001

Peripheral eosinophil (%)

3.8 ± 4.8

1.5 ± 1.0

2.7 ± 2.2

9.0 ± 7.1

< 0.001

Peripheral eosinophil count

419 ± 419

213 ± 100

318 ± 199

885 ± 603

< 0.001

BAL eosinophil (%)

46.8 ± 17.8

23.3 ± 9.3

53.4 ± 14.2

59.3 ± 12.4

< 0.001

BAL eosinophil count

382 ± 500

154 ± 137

502 ± 577

469 ± 558

< 0.001

CRP (unit)

9.5 ± 5.5

11.2 ± 4.9

10.2 ± 5.7

5.8 ± 3.8

< 0.001

Hospital days

11.0 ± 4.7

12.4 ± 6.3

10.6 ± 3.6

10.1 ± 3.6

0.009

ICU admission

96 (39.8)

33 (42.3)

55 (50.9)

8 (13.8)

< 0.001

ICU admission days

2.0 ± 1.3

2.1 ± 1.4

1.9 ± 1.2

2.3 ± 1.0

0.731

PF ratio at admission

261.9 ± 73.4

249.7 ± 65.8

253.8 ± 79.0

300.9 ± 59.9

0.003

O2 supply

0.031

None

52 (21.3)

11 (14.1)

20 (18.5)

21 (36.2)

Nasal or mask only

184 (75.4)

63 (80.8)

86 (79.6)

35 (60.3)

Mechanical ventilation

3 (1.2)

2 (2.6)

1 (0.9)

0 (0.0)

HFNC

5 (2.0)

2 (2.6)

1 (0.9)

2 (3.4)

Oxygen supply days

2.9 ± 1.5

3.4 ± 1.6

2.8 ± 1.4

2.3 ± 1.5

0.002

Steroid treatment days

14.3 ± 5.2

15.5 ± 5.8

14.0 ± 4.7

12.6 ± 4.7

0.006