Table 2 Lung function values for the cohort with full data available shown as absolute values (litres (L)), z-scores and intra-pair differences

FEV1 (L) follow-up

3.0 ± 0.7*

2.2 ± 0.5

FVC (L) follow-up

4.1 ± 0.9*

2.9 ± 0.6

FEV1/FVC follow-up

0.80 ± 0.09

0.82 ± 0.07

FEV1-change (L)

− 0.45 ± 0.4*

− 0.34 ± 0.2

FVC-change (L)

− 0.21 ± 0.6

− 0.18 ± 0.4

FEV1/FVC-change

0

0

zFEV1 follow-up

− 0.46 ± 1.33

− 0.42 ± 1.18

zFVC follow-up

− 0.23 ± 1.23

− 0.15 ± 1.04

zFEV1/FVC follow-up

− 0.47 ± 1.19

− 0.53 ± 0.97

zFEV1-change

0.03 ± 0.79

0.14 ± 0.73

zFVC-change

0.45 ± 0.92

0.57 ± 0.82

zFEV1/FVC-change

− 0.87 ± 1.18

− 0.86 ± 1.12

Intra-pair (IP) differences (median (min-max))

(86 pairs)

(83 pairs)

 ΔzFEV1_IP follow-up

0.7 (0.01–5.3)

0.6 (0.002–2.8)

 ΔzFVC_IP follow-up

0.6 (0.03–4.8)

0.6 (0.02–2.9)

 ΔzFEV1/FVC_IP follow-up

0.7 (0.02–3.9)

0.5 (0.01–2.5)

 ΔzFEV1-change_IP

0.7 (0.005–5.2)

0.5 (0.02–2.9)

 ΔzFVC-change_IP

0.7 (0.005–4.7)

0.6 (0.04–3.0)

 ΔzFEV1/FVC_IP-change_IP

1.1 (0.005–5.7)

1.0 (0.02–4.3)