Hospital outcomes in survivors by gestational week
| Gestational age, weeks | 22–24 (n=143) | 22 (n=23) | 23 (n=56) | 24 (n=64) | P value |
| ROP treatment | 35 (25) | 10 (45)* | 17 (30) | 8 (13)† | ns‡ <0.01§ <0.05¶ |
| NEC surgery | 15 (11) | 2 (9) | 5 (9)* | 8 (13)** | ns |
| PDA surgery | 51 (36) | 11 (48) | 21 (38)* | 19 (31)†† | ns |
| IVH III-IV | 9 (6) | 2 (9) | 3 (5) | 4 (6) | ns |
| PVL | 14 (10) | 5 (22) | 5 (9) | 4 (7)† | ns |
| Severe BPD | 65 (49) | 17 (77)* | 23 (43)†† | 25 (43)‡‡ | ns¶ <0.01‡ § |
| Length of stay, days | 125 (110–150) | 144 (131–208)†† | 131 (111–151)†† | 118 (104–32)§§ | <0.01§ <0.05‡ ¶ |
| Mechanical ventilation, days | 45 (27–57) | 53 (49–72)* | 45 (28–58)** | 34 (15–53)¶¶ | <0.01‡§ <0.05¶ |
Data presented as n (%) or median (IQR).
*Data missing, n:1.
†Data missing, n:4.
‡Week 22 vs 23.
§Week 22 vs 24.
¶Week 23 vs 24.
**Data missing, n:3.
††Data missing, n:2.
‡‡Data missing, n:6.
§§Data missing, n:11.
¶¶Data missing, n:7.
BPD, bronchopulmonary dysplasia; IVH, intraventricular haemorrhage; NEC, necrotising enterocolitis; PDA, patent ductus arteriosus; PVL, periventricular leukomalacia; ROP, retinopathy of prematurity.