Table 1 Patients’ baseline characteristics

Age

76 (70–80)

75.5 (64–79)

76 (71–81.5)

0.65

Male sex

66 (78)

32 (84)

34 (72)

0.3

IPF diagnosis

Honeycombing and/or surgical lung biopsy

78 (92)

35 (92)

43 (91)

1

Possible UIP with traction bronchiectasis

7 (8)

3 (8)

4 (9)

Surgical lung biopsy

16 (19)

5 (13)

11 (23)

0.274

HRCT pattern of AE

Diffuse

77 (91)

32 (84)

45 (96)

0.132

Multifocal

8 (9)

6 (16)

2 (4)

Corticosteroid use before admission

39 (46)

17 (45)

22 (47)

1

Immunosuppressant before admission

19 (22)

7 (18)

12 (26)

0.6

Antifibrotic drug before admission

15 (18)

10 (26)

5 (11)

0.086

Anticoagulant drug before admission

6 (7)

2 (5)

4 (9)

0.69

APACHE II score

16 (13–18)

15.5 (13–18)

16 (13–18)

0.546

PaO₂/FiO₂

165 (99–243)

159 (109–241)

167 (97–236)

0.933

Lactate dehydrogenase (IU/L)

340 (291–408)

323 (281–385)

355 (308–442)

0.079

C-reactive protein (mg/dl)

6.4 (3.0–11.1)

6.0 (2.9–9.0)

7.7 (3.2–12.6)

0.482

KL-6 (U/ml)

1280 (860–2110)

1085 (760–1703)

1380 (887–2430)

0.088

Surfactant protein D (ng/ml), n = 75

336 (222–515)

336 (248.5–567.5)

333 (211–494)

0.527