Perinatal characteristics and at gestational corrected age (GCA) of 1 year
| Non-BPD group (n=28) | BPD group (n=36) | Missing (BPD/non-BPD) | p-value | |
| Male | 18/28 (64%) | 24/36 (67%) | 0 | 0.84 |
| Weeks of pregnancy | 31.0±2.6 | 28.2±2.3 | 0 | <0.0001 |
| Birth weight g | 1484±440 | 1059±334 | 0 | <0.0001 |
| Birth weight percentiles | 52.5±29.6 | 51.6±31.3 | 0 | 0.91 |
| Surfactant therapy | 11/28 (39%) | 21/36 (58%) | 0 | 0.13 |
| Prenatal dexamethasone# | 7/28 (25%) | 16/36 (44%) | 0 | 0.11 |
| Postnatal dexamethasone | 0/28 (0%) | 20/36 (56%) | 0 | <0.0001 |
| HMD | 14/28 (50%) | 27/36 (75%) | 0 | 0.036 |
| PIPmax | 8.2±10.9 | 24.7±7.5 | 5/5 | <0.0001 |
| FIO2 at 36 weeks | 0.21 | 0.29±0.08 | 6/0 | <0.0001 |
| GCA at lung function testing months | 9.7±3.8 | 10.4±3.0 | 1/1 | 0.47 |
| CHL at lung function testing cm | 71±9 | 71±7 | 2/1 | 0.73 |
| FRC z-score for CHL | 0.05±1.03) | 0.37±1.31 | 2/1 | 0.30 |
| Compliance z-score for CHL | 0.32±1.03 | −0.56±0.82 | 3/1 | 0.0005 |
| Mixing efficiency % | 56±10 | 43±17 | 2/2 | 0.0012 |
Data are presented as mean±sd or n/N (%), unless otherwise stated. Mean weeks of pregnancy and mean birth weight were significantly different between groups. GCA in months for some patients was less than 12 months because they could not be tested at GCA 12 months. Mean PIPmax: mean maximum positive inspiratory pressure during mechanical ventilation in cmH2O; mean FIO2 at 36 weeks: fractional inspired oxygen concentration in ambient air at post-conceptional age of 36 weeks; GCA: gestational corrected age; BPD: bronchopulmonary dysplasia; CHL: crown–heel length; HMD: hyaline membrane disease; PIPmax: maximum positive inspiratory pressure; FIO2: inspiratory oxygen fraction. #: Prenatal dexamethasone was administered ante partum to mothers if admitted on time before delivery to the hospital.