Table 1 Clinical characteristics of the study subjects

Number

1328

126

–

Age (years)

46.27 ± 0.43

51.2 ± 1.16

1.05E−04

Sex (male %)

38.10%

41.30%

0.503

Number of exacerbation in the first year

0.25 ± 0.02

2.03 ± 0.11

1.21E−32

Smoking status (non-smokers/ex-smokers/smokers, %)

66.3/18.5/15.1%

58.7%/22.2%/19.1%

0.086

Smoking amount (pack-year)

5.86 ± 0.36

8.47 ± 1.46

0.084

Atopy (%)

48.80%

39.70%

0.05

Duration of asthma (years)

3.06 ± 0.2

5.95 ± 0.94

0.003

Duration of follow-up (years)

6.17 ± 0.12

7.29 ± 0.37

0.007

Serum total IgE (IU/ml)

356.3 ± 18.87

453.17 ± 62.05

0.131

Body mass index (kg/m²)

23.87 ± 0.12

23.96 ± 0.47

0.859

Baseline FVC%, predicted

83.02 ± 0.48

67.65 ± 1.4

1.45E−20

Baseline FEV1%, predicted

82.58 ± 0.6

58.4 ± 1.59

3.06E−30

Baseline FEV1/FVC

75.64 ± 0.34

64.81 ± 1.15

6.96E−20

PC20, methacholine (mg/ml) (No. of study subjects)

7.6 ± 0.29 (1,218)

5.52 ± 0.83 (109)

0.037

Total ICS dosage used in the 1st year (Fluticasone eqv./day)

211.36 ± 7.25

571.34 ± 43.82

3.16E−13

Systemic prednisolone dose in the 1st year (mg/year)

80.31 ± 9.55

564.14 ± 95.39

1.51E−06