Table 1 Patient demographics and baseline characteristics, based on CID using D1 and D2

Demographics

Age, years

69.6 ± 7.8

69.8 ± 7.5

69.4 ± 8.2

70.1 ± 7.2

69.4 ± 8.1

Female, N (%)

15 (5.8%)

7 (4.6%)

8 (7.5%)

4 (4.1%)

11 (6.8%)

Body mass index, kg/m²

22.2 ± 3.2

22.1 ± 3.3

22.5 ± 3.2

22.0 ± 3.2

22.4 ± 3.3

Current smoker, N (%)

73 (28.2%)

39 (25.7%)

34 (31.8%)

21 (21.7%)

52 (32.1%)

Pack-years

56.0 (43.0–78.0)

56.0 (43.0–75.8)

57.0 (43.0–79.5)

55.0 (42.0–73.5)

56.6 (43.5–82.0)

Pulmonary function test

Post-BD FEV_1, L

1.7 ± 0.7

1.7 ± 0.7

1.8 ± 0.7

1.6 ± 0.6

1.8 ± 0.7

Post-BD FEV₁, % predicted

64.5 ± 21.9

62.3 ± 21.8

67.8 ± 21.6

59.2 ± 20.9

67.8 ± 21.9

Post-BD FEV₁/FVC, %

51.1 ± 12.5

49.6 ± 12.6

53.2 ± 12.1

48.2 ± 12.7

52.8 ± 12.2

DLco, % predicted

78.1 ± 25.0

76.2 ± 24.8

80.7 ± 25.2

77.3 ± 24.8

78.5 ± 25.2

Kco, % predicted

63.8 ± 24.3

62.6 ± 24.7

65.4 ± 23.7

63.3 ± 24.6

64.0 ± 24.2

Patient-reported outcomes

Chronic bronchitis, N (%)

29 (11.2%)

16 (10.5%)

13 (12.2%)

13 (13.4%)

16 (9.9%)

mMRC dyspnea scale ≥ 2, N (%)

137 (52.9%)

84 (55.3%)

53 (49.5%)

55 (56.7%)

82 (50.6%)

SGRQ total score

31.8 ± 17.4

32.4 ± 17.4

31.1 ± 17.4

33.8 ± 17.3

30.7 ± 17.3

CT emphysema score

1.2 (0.7–2.0)

1.2 (0.8–2.2)

1.1 (0.6–2.0)

1.2 (0.7–2.0)

1.2 (0.7–2.2)

Comorbidities

Any cardiovascular disease

58 (22.4%)

33 (21.7%)

25 (23.4%)

23 (23.7%)

35 (21.6%)

Ischemic heart disease

18 (7.0%)

10 (6.6%)

8 (7.5%)

6 (6.2%)

12 (7.4%)

Diabetes

12 (4.6%)

4 (2.6%)

8 (7.5%)

3 (3.1%)

9 (5.6%)