Table 3 Correlation between percentage of IL-4-expressing Th2 cells, and demographic characteristics and key features of COPD

Age (years)^a

p = 0.57

p = 0.49

r = − 0.11

r = 0.14

Sex (male/female)^b

p = 0.42

p = 0.68

Smoking (pack years)^a

p = 0.95

r = 0.32

r = 0.01

r = 0.20

Smoking (ex-smokers vs current-smokers)^b

p = 0.70

p = 0.06

Chronic bronchitis (yes/no)^b

p = 0.25

p = 0.16

Dyspnea scale (mMRC)^a

p = 0.83

p = 0.18

r = 0.04

r = − 0.26

FEV₁ (%)^a

p = 0.66

p = 0.19

r = − 0.08

r = − 0.25

FVC (%)^a

p = 0.76

p = 0.34

r = 0.06

r = − 0.19

FEV₁/FVC (%)^a

p = 0.25

p = 0.51

r = − 0.21

r = − 0.13

RV (%)^a

p = 0.07

p = 0.71

r = 0.32

r = 0.07

TCL (%)^a

p = 0.11

p = 0.53

r = 0.30

r = 0.02

RV/TCL (%)^a

p = 0.56

p = 0.49

r = 0.11

r = 0.02

Emphysema (yes/no)^b

p = 0.44

p = 0.88

Emphysema score^a

p = 0.40

p = 0.48

r = 0.16

r = 0.14

Eosinophils (%)^a

p = 0.14

p = 0.17

r = − 0.28

r = 0.26

Eosinophils (total count)^a

p = 0.52

p = 0.71

r = − 0.12

r = 0.07

Exacerbations (n per year)^a

p = 0.82

p = 0.46

r = 0.04

r = − 0.15

ICS (yes/no)^b

p = 0.27

p = 0.50