Table 3 Comparison of lung function, impulse oscillometry, and radiographic measurements of subjects by fixed ratio-defined lung function categories

Lung Function

Before bronchodilator use

MMEF, L/s

2.01 ± 0.84

1.29 ± 0.54*^†

0.78 ± 0.40

MMEF% of predicted, %

80.6 ± 29.4

54.1 ± 19.0*^†

31.9 ± 15.1

FEF50, L/s

2.76 ± 1.04

1.84 ± 0.74*^†

1.07 ± 0.60

FEF50% of predicted, %

83.7 ± 27.6

57.8 ± 19.5*^†

32.7 ± 17.1

FEF75, L/s

0.66 ± 0.39

0.42 ± 0.23*^†

0.26 ± 0.14

FEF75% of predicted, %

70.9 ± 36.4

47.5 ± 21.4*^†

30.2 ± 15.2

After bronchodilator use

MMEF, L/s

2.32 ± 0.85

1.51 ± 0.60*^†

0.86 ± 0.41

MMEF% of predicted, %

93.3 ± 29.4

63.7 ± 23.7*^†

34.9 ± 15.0

FEF50, L/s

3.13 ± 1.03

2.07 ± 0.72*^†

1.19 ± 0.62

FEF50% of predicted, %

95.1 ± 27.1

65.5 ± 20.3*^†

36.3 ± 17.3

FEF75, L/s

0.80 ± 0.43

0.52 ± 0.32*^†

0.28 ± 0.14

FEF75% of predicted, %

85.6 ± 41.8

59.4 ± 33.9*^†

32.8 ± 15.1

Impulse oscillometry§

R5^¶, kPa/L/s

0.31 ± 0.09

0.36 ± 0.11*^†

0.37 ± 0.13

R20^¶, kPa/L/s

0.27 ± 0.07

0.29 ± 0.07*^†

0.28 ± 0.07

R5-R20^¶, kPa/L/s^‡

0.04 (0.02 to 0.06)

0.06 (0.03 to 0.10)*^†

0.07 (0.03 to 0.14)

AX, kPa/L^‡

0.24 (0.15 to 0.40)

0.44 (0.27 to 0.73)*^†

0.56 (0.23 to 1.51)

X5, kPa/L/s

-0.09 ± 0.04

-0.12 ± 0.04*^†

-0.15 ± 0.10

Fres, Hz

12.39 ± 3.45

15.24 ± 4.31*^†

17.81 ± 6.82

Radiographic measurements

LAA_− 950, %^‡

0.31 (0.11 to 0.78)

0.25 (0.09 to 0.66)*^†

2.00 (0.67 to 5.92)

Perc 15, HU

-905 ± 20

-895 ± 30*^†

-920 ± 24

LAA_− 856, %^‡

3.55 (1.11 to 8.42)

5.08 (1.87 to 11.6)^†

25.87 (11.66 to 45.19)

HAA_{− 600 to −250}, %^‡

3.55 (3.19 to 4.06)

3.80 (3.42 to 4.66)^*†

3.56 (3.16 to 4.09)

MLD_E/I

0.82 ± 0.06

0.86 ± 0.06*^†

0.91 ± 0.06

TLC_CT, L

4.78 ± 1.05

4.15 ± 0.98*^†

5.45 ± 1.13

TLC_CT % of predicted, %

87.7 ± 22.0

76.7 ± 22.2*^†

117.7 ± 35.4

RV_CT, L^‡

2.17 (1.82 to 2.59)

2.15 (1.81 to 2.52)^†

3.29 (2.68 to 4.06)

RV_CT % of predicted, %^‡

103.1 (85.2 to 123.4)

101.4 (83.0 to 120.7)^†

160.4 (123.9 to 201.1)

RV/TLC_CT^‡

0.46 (0.40 to 0.52)

0.52 (0.46 to 0.63)*^†

0.61 (0.51 to 0.74)