Table 2 mMRC Dyspnea Scale, the 6-min walking test, and prebronchodilator spirometry among the three groups

mMRC dyspnea Scale

3 (1–4)

0 (0–1)

0 (0–0)

< 0.001*

P1< 0.001*

P2< 0.001*

P3= 0.088

Six-min walking test (m)

136.66 (116.24–184.96)

450 (144.15–632.5)

700 (660–755)

< 0.001*

P1< 0.001*

P2< 0.001*

P3= 0.006*

FEV1%

48.76± 19.42

78.51± 21.77

94.68± 4.42

< 0.001*

P1< 0.001*

P2< 0.001*

P3= 0.103

FVC %

72.33± 20.49

84.17± 23.22

99.9± 7.81

< 0.001*

P1< 0.001*

P2< 0.001*

P3= 0.158

FEV1/FVC ratio

52.41± 10.89

73.84± 18.3

96.8± 17.17

< 0.001*

P1< 0.001*

P2< 0.001*

P3< 0.001*