Perinatal data for 83 subjects born extremely preterm (EP) with and without neonatal BPD and 81 control subjects born at term
| 1991–1992 Cohort | 1982–1985 Cohort | |
|---|---|---|
| Subjects, n (%) | ||
| Control | 35 | 46 |
| All EP | 35 | 48† |
| EP non-BPD | 9 (26) | 11 (23) |
| EP mild BPD | 14 (40) | 24 (50) |
| EP m/s BPD | 12 (34) | 13 (27) |
| Female gender, n (%) | ||
| Control | 22 (63) | 21 (46) |
| All EP | 22 (63) | 21 (44) |
| EP non-BPD | 7 (78) | 5 (45) |
| EP mild BPD | 10 (71) | 11 (46) |
| EP m/s BPD | 5 (42) | 5 (38) |
| Birth weight (g), mean (range) | ||
| Control | 3564 (3010–4000) | 3441 (3000–4000) |
| All EP | 933 (570–1400) | 1012 (580–1480) |
| EP non-BPD | 1053 (930–1400) | 1151 (960–1480) |
| EP mild BPD | 927 (620–1370) | 1013 (580–1340) |
| EP m/s BPD | 851 (570–1200) | 892 (670–1080)** |
| Gestational age (weeks), mean (range) | ||
| All EP | 26.9 (23–31) | 27.3 (23–32) |
| EP non-BPD | 28.3 (26–31) | 28.5 (27–32) |
| EP mild BPD | 26.5 (24–28) | 27.0 (23–28) |
| EP m/s BPD* | 25.8 (23–28)* | 27.2 (26–30) |
| Gestational age at room air (weeks), median (range) | ||
| All EP | 34.0 (28–50) | 34.0 (28–63) |
| EP non-BPD | 29.0 (28–31) | 30.0 (28–34) |
| EP mild BPD | 33.5 (30–35) | 33.0 (31–35) |
| EP m/s BPD | 37.5 (36–50)*** | 37.0 (36–63)*** |
| Postnatal days with oxygen treatment, median (range) | ||
| All EP | 49.0 (2–180) | 42.0 (1–257) |
| EP non-BPD | 2.0 (2–26) | 11.0 (1–25) |
| EP mild BPD | 45.5 (28–70) | 41.0 (28–71) |
| EP m/s BPD | 91.5 (61–180)*** | 70.0 (44–257)*** |
| Ventilator days, median (range) | ||
| All EP | 4.0 (0–54.5) | 8.0 (0–54.0) |
| EP non-BPD | 0.5 (0–1.7) | 0.3 (0–4.8) |
| EP mild BPD* | 3.0 (0–40.0) | 8.6 (0.8–35) |
| EP m/s BPD | 12.7 (1.7–54.5)** | 25.2 (0.7–54.0)** |
| Antenatal steroids, n (%) | ||
| All EP | 15/34 (44) | 16/47 (34) |
| EP non-BPD | 3 (33) | 5 (45) |
| EP mild BPD* | 8 (57) | 5/23 (22) |
| EP m/s BPD | 4/11 (36) | 6 (46) |
| Surfactant, n (%) | ||
| All EP | 17 (49) | – |
| EP non-BPD | 1 (11) | – |
| EP mild BPD | 6 (43) | – |
| EP m/s BPD | 10 (83)** | – |
| Postnatal steroids, n (%) | ||
| All EP | 10 (29) | 4/47 (9) |
| EP non-BPD | 0 (0) | 0 (0) |
| EP mild BPD | 2 (14) | 1/23 (4) |
| EP m/s BPD* | 8 (67)** | 3 (23) |
†Complete neonatal data available for 47/48 preterm-born subjects in the older cohort.
Group comparisons were performed with the Student t test (normal distribution), Mann–Whitney U test (asymmetrical continuous distribution) or Pearson exact χ2 test (categorical data) and results expressed as *p<0.05, **p<0.01, ***p<0.001 (column 1 regarding cohort differences and columns 2 and 3 regarding within-cohort subgroup differences in BPD).
BPD, bronchopulmonary dysplasia; EP, subjects born extreme preterm (ie, gestational age ≤28 weeks or birth weight ≤1000 g); m/s BPD, moderate/severe BPD (ie, oxygen supplement at gestational age 36 weeks); mild BPD, oxygen supplement at 28 postnatal days.