Table 1.
Background characteristics of 5296 preterm infants born before 32 weeks gestation by four Norwegian health regions
| South-East n = 2919 |
West n = 1217 |
Mid n = 730 |
North n = 430 |
P value | |
|---|---|---|---|---|---|
| Background | |||||
| GA (weeks), median (IQR) | 29 + 3 (27 + 1–31 + 0) | 29 + 3 (27 + 3–30 + 6) | 29 + 4 (27 + 3–31 + 0) | 29 + 4 (27 + 2–31 + 4) | 0.963 |
| BW (g), median (IQR) | 1199 (875–1505) | 1225 (903–1516) | 1225 (899–1510) | 1200 (895–1730) | 0.447 |
| SGA (%) | 27.2 | 24.9 | 25.2 | 29.1 | 0.520 |
| Apgar 5 min, median (IQR) | 8 (7–9) | 8 (6–9) | 8 (7–9) | 8 (7–9) | 0.272 |
| CRIB 2 score, median (IQR) | 7 (4–10) | 6 (4–9) | 6 (3–9) | 6 (4–10) | 0.234 |
| Caesarean delivery (%) | 41.9 | 60.1 | 71.8 | 45.6 | <0.001a |
| Antenatal steroids (%) | 85.2 | 86.2 | 87.9 | 81.4 | 0.021b |
| Female (%) | 44.2 | 46.1 | 44.4 | 47.9 | 0.402 |
| Exposures | |||||
| Days of mechanical ventilation per 1000 PD | 113 | 62 | 136 | 92 | 0.104 |
| Days of central lines per 1000 PD | 273 | 100 | 182 | 149 | <0.001c |
| Days of hospitalization, median (IQR) | 49 (33–74) | 50 (34–73) | 50 (34–75) | 56 (41–79) | <0.001d |
| Outcomes | |||||
| Severe BPD (%) | 13.9 | 9.8 | 14.1 | 17.7 | <0.001c |
| Severe ROP (%) | 2.4 | 4.3 | 2.2 | 3.0 | 0.006c |
| Surgically treated NEC (%) | 1.7 | 1.8 | 1.4 | 2.3 | 0.646 |
| In-hospital mortality (%) | 8.5 | 9.0 | 9.5 | 8.4 | 0.828 |
| Age at death (days), median (IQR) | 7 (2–21) | 6 (1–16) | 3 (1–20) | 4 (2–20) | 0.162 |
Severe BPD: need for any respiratory support, other than O2 only, at 36 weeks + 0–6 days PMA; one value was missing. Severe ROP (receiving therapy with laser or anti-vascular endothelial growth factor): nine values were missing. Central lines (include any of the following: umbilical artery and/or vein, peripherally inserted central catheter and central venous catheter): four values were missing. CRIB 2: 290 values were missing
aSignificant differences between all regions except between South-East and North.
bSignificant differences between Mid and North.
cSignificant differences between West and all other regions.
dSignificant differences between North and all other regions.