Table 2 Main clinical characteristics of the study population

Mean age, years (IQR)

69.5 (66–75)

63.6 (56–70)

66.7 (60.3–74)

Male sex, n (%)

27 (52)

9 (24.3)

35 (39.3)

Current smokers, n (%)

5 (9.6)

12 (32.4)

17 (19.1)

BMI (kg/m²)

29.3 (9.4)

28.6 (9.6)

29.0 (9.4)

 1

7 (13.5)

N/A

N/A

 2

16 (30.7)

N/A

N/A

 3

12 (23.1)

N/A

N/A

 4

16 (30.7)

N/A

N/A

 N/A

1 (1.9)

N/A

N/A

FEV₁, liters (SD)

1.47 (0.77)

2.60 (0.77)

1.95 (0.95)

FEV₁, % of predicted (SD)

58.4 (74.4)

92.5 (16.4)

83.1 (47.6)

FVC, liters (SD)

2.71 (1.06)

3.25 (0.90)

2.94 (1.02)

FVC, % of predicted (SD)

77.5 (60.0)

89.9 (19.2)

83.1 (48.6)

FEV₁/FVC ratio

0.49 (0.13)

0.80 (0.05)

0.62 (0.19)

6 MWD, meters (SD)

340 (134)

455 (110)

391 (137)

SF36 PCS (SD)

36.3 (10.6)

50.8 (8.2)

42.4 (12.0)

SF36 MCS (SD)

53.4 (9.1)

52.6 (11.4)

53.1 (10.1)