Table 1 Baseline characteristics of patients in study 1 and study 2

Age, years

61.7 ± 10.8

64.0 ± 9.8

0.543

67.9 ± 11.6

Male

5 (55.6)

22 (78.6)

0.215

137 (62.8)

Ethnicity

0.665

 Caucasian

9 (100)

24 (85.7)

173 (79.4)

 First nations

0 (0)

3 (10.7)

24 (11.1)

 African

0 (0)

1 (3.6)

1 (0.5)

 Others

0 (0)

0 (0)

20 (9.2)

Smoking status

0.462

 Former

3 (33.3)

14 (50)

84 (38.5)

 Current

6 (66.7)

14 (50)

122 (56.0)

 Pack-year smoked

28.2 ± 22.3 (n = 5)

33.7 ± 39.3 (n = 16)

0.771

12 (5.5)

 FEV₁/FVC, %

60.2 ± 9.7 (n = 6)

52.1 ± 15.1 (n = 21)

0.227

56.2 ± 15.7 (n = 78)

 FEV₁, % predicted

78.4 ± 12.1 (n = 7)

53.3 ± 21.8 (n = 23)

0.007

55.0 ± 21.3 (n = 102)

 FVC, % predicted

104 ± 18 (n = 7)

83.7 ± 18.5 (n = 21)

0.020

76.3 ± 22.3 (n = 78)

GOLD grades

n = 7

n = 23

0.096

n = 102

 1 or 2

4 (57.1)/3 (42.9)

3 (13.0)/11 (47.8)

15 (14.7)/47 (46.1)

 3 or 4

0 (0)/0 (0)

5 (21.7)/4 (17.4)

24 (23.5)/16 (15.7)

Asthma

3 (33.3)

9 (32.1)

1.000

52 (24.1) (n = 216)

White blood cells (×  10³/μL)

6.48 ± 1.11

7.21 ± 1.95

0.296

9.58 ± 4.76 (n = 121)

 Neutrophil, %

63.5 ± 5.0

62.5 ± 10.3

0.620

79.2 ± 14.1 (n = 120)

 Monocyte, %

5.99 ± 1.21

5.90 ± 1.44

0.790

6.09 ± 3.82 (n = 120)

 Eosinophil, %

2.94 ± 1.34

4.13 ± 4.48

0.832

0.87 ± 1.36 (n = 120)

 Basophil, %

0.56 ± 0.26

0.61 ± 0.25

0.484

1.74 ± 7.29 (n = 120)

 Lymphocyte, %

24.5 ± 5.0

24.6 ± 8.2

0.818

11.9 ± 8.8 (n = 120)

 Bronchodilator

8 (88.9)

24 (85.7)

1.000

216 (99.1)

 Inhaled corticosteroid

4 (44.4)

23 (82.1)

0.041

163 (74.8)