. 2019 May 24;20:102. doi: 10.1186/s12931-019-1075-1

Table 3.

Lung function in each study group

	BPD n = 26	Preterm n = 23	Asthma n = 23	Healthy controls n = 24
FEV₁ z-scores^a	−0.94*** (− 1.57; −0.08)	0.28 (−0.27; 1.18)	0.14 (−0.52; 0.77)	0.78 (−0.03; 1.26)
FEV₁% pred.^a	88.9*** (81.4; 99.1)	103.3 (96.9; 113.3)	101.7 (94.1; 109.0)	108.9 (99.7; 114.1)
FVC z-scores^a	−0.32* (− 1.24; 0.14)	− 0.26 (− 0.64; 0.60)	0.13 (− 0.48; 0.85)	0.37 (− 0.18; 0.85)
FVC % pred.^a	96* (85.6; 101.7)	96.9 (92.2; 107.5)	101.6 (94.5; 110.4)	104.6 (97.9; 109.8)
FEV₁/FVC^b	0.82*** (0.79; 0.85)	0.91 (0.87; 0.94)	0.86 (0.83; 0.89)	0.90 (0.87; 0.93)
FEV₁/FVC z-scores ^a	−0.67*** (−1.86; 0.18)	0.82 (0.13; 1.33)	−0.20* (− 0.43; 0.33)	0.42 (− 0.26; 0.89)
Reversibility %	6.9 (3.3; 10.9)	3.7 (1.4; 7.6)	5.9 (3.7; 8.3)	4.3 (1.9; 6.2)
Methacholine challenge pos.	19 (73)	13 (56)	23 (100)	0
TLC % pred.^a	95* (87.5; 101.5)	97 (92; 114)	99 (95; 106)	104 (95.5; 108)
RV % pred.^a	88 (60.5; 99.5)	79 (65; 132)	72.5 (52; 96)	84.5 (68.5; 105.5)
VC % pred.^a	96.5** (88; 106)	103 (96; 110)	106 (99; 113)	107 (100.5; 115.5)
RV/TLC	20 (17; 24.5)	20.5 (17.5; 22.5)	18.5 (14; 23)	19 (17; 22.5)
D_{LCO adj} % pred.^a	67*** (64; 73)	73*** (65; 83)	81.5 (75; 91)	86.5 (80; 96)
LCI^a	6.97*** (6.84; 7.72)	6.73 (6.29; 7.12)	6.75 (6.37; 7.08)	6.50 (6.31; 6.72)
R_5–20 (kPa/L/sec)^b	0.014 (−0.002; 0.030)	0.021 (0.003; 0.039)	0.015 (−0.003; 0.033)	0.007 (− 0.010; 0.024)
AX^0.5 (kPa/L)^b	0.156 (0.120; 0.192)	0.163 (0.123; 0.202)	0.140 (0.099; 0.181)	0.125 (0.086; 0.164)

BPD
n = 26

Preterm
n = 23

Asthma
n = 23

Healthy controls
n = 24

FEV₁ z-scores^a

−0.94***

(− 1.57; −0.08)

0.28

(−0.27; 1.18)

0.14

(−0.52; 0.77)

0.78

(−0.03; 1.26)

FEV₁% pred.^a

88.9***

(81.4; 99.1)

103.3

(96.9; 113.3)

101.7

(94.1; 109.0)

108.9

(99.7; 114.1)

FVC z-scores^a

−0.32*

(− 1.24; 0.14)

− 0.26

(− 0.64; 0.60)

0.13

(− 0.48; 0.85)

0.37

(− 0.18; 0.85)

FVC % pred.^a

96*

(85.6; 101.7)

96.9

(92.2; 107.5)

101.6

(94.5; 110.4)

104.6

(97.9; 109.8)

FEV₁/FVC^b

0.82***

(0.79; 0.85)

0.91

(0.87; 0.94)

0.86

(0.83; 0.89)

0.90

(0.87; 0.93)

FEV₁/FVC

z-scores ^a

−0.67***

(−1.86; 0.18)

0.82

(0.13; 1.33)

−0.20*

(− 0.43; 0.33)

0.42

(− 0.26; 0.89)

Reversibility %

6.9

(3.3; 10.9)

3.7

(1.4; 7.6)

5.9

(3.7; 8.3)

4.3

(1.9; 6.2)

Methacholine challenge pos.

19 (73)

13 (56)

23 (100)

TLC % pred.^a

95*

(87.5; 101.5)

(92; 114)

(95; 106)

104

(95.5; 108)

RV % pred.^a

(60.5; 99.5)

(65; 132)

72.5

(52; 96)

84.5

(68.5; 105.5)

VC % pred.^a

96.5**

(88; 106)

103

(96; 110)

106

(99; 113)

107

(100.5; 115.5)

RV/TLC

(17; 24.5)

20.5

(17.5; 22.5)

18.5

(14; 23)

(17; 22.5)

D_{LCO adj} % pred.^a

67***

(64; 73)

73***

(65; 83)

81.5

(75; 91)

86.5

(80; 96)

LCI^a

6.97***

(6.84; 7.72)

6.73

(6.29; 7.12)

6.75

(6.37; 7.08)

6.50

(6.31; 6.72)

R_5–20

(kPa/L/sec)^b

0.014

(−0.002; 0.030)

0.021

(0.003; 0.039)

0.015

(−0.003; 0.033)

0.007

(− 0.010; 0.024)

AX^0.5

(kPa/L)^b

0.156

(0.120; 0.192)

0.163

(0.123; 0.202)

0.140

(0.099; 0.181)

0.125

(0.086; 0.164)

BPD-, Preterm- and asthma- groups were compared to healthy controls. Data are presented as median (IQR) numbers (%). All dynamic spirometry measures (FEV₁, FVC, FEV₁/FVC) and the impulse oscillometry data (R_5–20, AX) are post bronchodilator (four doses of salbutamol 0.1 mg/dose) measures

^aAnalysis with quantile regression on median

^bAnalysis with quantile regression on median adjusting for age, sex and height

*p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001, comparing BPD-, preterm- and asthma-groups to healthy controls

Abbreviations: BPD bronchopulmonary dysplasia, FEV₁ forced expiratory volume in 1 s, FVC forced vital capacity, TLC total lung capacity, RV residual volume, VC vital capacity, D_{LCO adj} diffusing capacity of the lung for Carbon monoxide adjusted for blood haemoglobin, LCI lung clearance index, R_5–20 resistance at 5–20 Hz, AX^0.5 square root of the area of reactance, IQR Inter quartile range