Table 1 Baseline characteristics of fibrotic hypersensitivity pneumonitis patients as classified by cluster

Age, years

65.3 ± 10.9

68.0 ± 9.7

60.9 ± 12.5

63.5 ± 10.9

Male

160 (47.6)

73 (46.2)

21 (45.7)

66 (50.0)

Ever smoking

147 (43.8)

72 (45.6)

17 (37.0)

58 (43.9)

BMI, kg/m²

31.3 ± 6.6

31.6 ± 6.1

27.5 ± 5.8

32.1 ± 7.0

HRCT pattern

 - Typical HP

 - Compatible with HP

 - Indeterminate for HP

222 (66.0)

59 (17.6)

55 (16.4)

103 (65.2)

26 (16.5)

29 (18.4)

36 (78.3)

8 (17.4)

2 (4.4)

83 (62.9)

25 (18.9)

24 (18.2)

Histopathologic findings

 - No tissue biopsy

 - HP

 - Probable HP

 - Indeterminate for HP

107 (31.9)

134 (39.9)

39 (11.6)

56 (16.6)

60 (38.0)

59 (37.4)

16 (10.1)

23 (14.5)

18 (39.1)

19 (41.3)

3 (6.5)

6 (13.1)

29 (22.0)

56 (42.4)

20 (15.2)

27 (20.4)

Diagnostic confidence

 - Definite diagnosis

 - High confidence

 - Moderate confidence

 - Low confidence

133 (39.6)

31 (9.2)

101 (30.1)

71 (21.1)

57 (36.1)

13 (8.2)

51 (32.3)

37 (23.4)

22 (47.8)

0 (0.0)

17 (37.0)

7 (15.2)

54 (40.9)

18 (13.6)

33 (25.0)

27 (20.5)

Identifiable causative antigen

 - Any exposure

 - Bird proteins

 - Farm environment

 - Domestic antigens

 - Hot tub/sauna

 - Other specific environments

 - Multiple exposures

202 (60.1)

117 (34.8)

47 (14.0)

50 (14.9)

8 (2.4)

9 (2.7)

47 (14.0)

99 (62.7)

60 (38.0)

25 (15.8)

23 (15.6)

2 (1.3)

3 (1.9)

21 (13.3)

39 (84.8)

23 (50.0)

7 (15.2)

7 (15.2)

5 (10.9)

1 (2.2)

8 (17.4)

64 (48.5)

34 (25.8)

15 (11.4)

20 (15.2)

1 (0.8)

5 (3.8)

18 (13.6)

< 0.001

0.006

0.53

1.00

0.003

0.66

0.76

Positive serum specific IgG

 - Any specific IgG

 - IgG against bird proteins

 - IgG against mold

 - IgG against bacteria

148 (44.1)

101(30.1)

73 (21.7)

27 (8.0)

63 (39.9)

45 (28.5)

31 (19.6)

8 (5.1)

32 (69.6)

24 (52.2)

13 (28.3)

6 (13.0)

53 (40.2)

32 (24.2)

29 (22.0)

13 (9.9)

0.001

0.002

0.43

0.11

Identifiable nontuberculous mycobacterium

4 (1.2)

1 (0.6)

2(4.4)

1 (0.8)

Identifiable causative exposures confirmed by serum specific IgG

93 (27.7)

41 (26.0)

24 (52.2)

28 (21.2)

Mosaic attenuation on HRCT

280 (83.3)

129 (81.7)

43 (93.5)

108 (81.8)

Honeycombing cysts on HRCT

61 (18.2)

29 (18.4)

5 (10.9)

27 (20.5)

UIP pattern on HRCT

21 (6.3)

10 (6.3)

0 (0)

11 (8.33)

Baseline pulmonary function test, %predicted

 - FVC

 - FEV₁

 - FEV₁/FVC ratio*

 - FEF_{25 − 75%}

 - DL_CO

 - TLC

 - RV

 - RV/TLC ratio

65.6 ± 16.7

68.6 ± 17.5

0.81 ± 0.09

90.4 ± 43.6

50.0 ± 15.5

72.5 ± 15.8

82.9 ± 32.4

111.7 ± 27.0

78.2 ± 10.9

83.2 ± 10.5

0.82 ± 0.06

114.5 ± 43.2

55.8 ± 13.9

78.4 ± 10.7

78.2 ± 17.9

97.5 ± 14.8

63.8 ± 16.1

57.8 ± 14.6

0.69 ± 0.13

44.5 ± 25.1

57.2 ± 16.6

90.8 ± 16.3

139.9 ± 42.3

151.8 ± 30.5

51.1 ± 9.0

54.8 ± 9.2

0.83 ± 0.06

77.4 ± 28.3

40.5 ± 11.6

59.2 ± 8.6

68.6 ± 17.5

114.8 ± 21.6

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

< 0.001

Co-morbidities

 - Diabetes mellitus

 - Hypertension

 - COPD

 - Gastroesophageal reflux

 - Coronary arterial disease

 - OSA

 - Pulmonary hypertension

 - Anxiety/depression

44 (13.1)

114 (33.9)

46 (13.7)

76 (22.6)

71 (21.1)

94 (28.0)

63 (18.8)

32 (9.5)

21 (13.3)

57 (36.1)

24 (15.2)

44 (27.9)

41 (26.0)

56 (35.4)

17 (17.1)

18 (11.4)

4 (8.7)

12 (26.1)

7 (15.2)

7 (15.2)

7 (15.2)

5 (10.9)

5 (10.9)

2 (4.4)

19 (14.4)

45 (34.1)

15 (11.4)

25 (18.9)

23 (17.2)

33 (25.0)

31 (13.5)

12 (9.1)

0.68

0.46

0.59

0.09

0.13

0.002

0.14

0.40

Treatment (throughout the follow-up period)

 - No treatment

 - Corticosteroids

 - Steroid-sparing agent

 - Antigen avoidance

42 (12.5)

288 (85.7)

133 (39.6)

114 (33.9)

21 (13.3)

134 (84.8)

59 (37.3)

59 (37.3)

12 (26.1)

34 (73.9)

11 (23.9)

23 (50)

9 (6.8)

120 (90.9)

63 (47.7)

32 (24.2)

0.003

0.02

0.01

0.004