Table 2.
Univariable Analysis of Risk factors for BPD (n=598)
| Factor | BPD (n=240) |
No BPD (n=358) |
Relative Risk (95%) CI |
Relative risk per |
|---|---|---|---|---|
| Supplemental enteral iron, median mg (IQR) | 70 (24-194) | 59 (11-172) | 1.02 (0.98, 1.06) | 50 mg increase |
| Age at first enteral iron dose, median d (IQR)a | 24 (15, 42) | 14 (11, 25) | 1.16 (1.12, 1.19) | Per 7 day increase |
| Volume of RBC transfused, median ml (IQR) | 56 (24-105) | 0 (0-22) | 1.14 (1.11, 1.18) | 20 ml increase |
| Gestational age at birth, median weeks (IQR) | 26 (25, 27) | 29 (28, 30) | 0.73 (0.71, 0.76) | 1 week increase |
| Small for gestational age, n (%) | 44 (18%) | 94 (26%) | 0.74 (0.57, 0.98) | yes vs. no |
| Birth weight, median g (IQR) | 800 (682-979) | 1158 (983-1325) | 0.78 (0.75, 0.81) | 100 g increase |
| Received ≥ 1 dose of antenatal steroids, n (%) | 200 (83%) | 301 (84%) | 0.98 (0.75, 1.27) | yes vs. no |
| Score for Neonatal Acute Physiology, median (IQR) | 12 (10-15) | 9 (4-13) | 1.07 (1.05, 1.08) | 1 unit increase |
| Positive airway pressure on DOB, n (%) | 222 (93%) | 310 (87%) | 1.53 (1.02, 2.30) | yes vs. no |
| Surfactant on DOB, n (%) | 151 (63%) | 97 (27%) | 2.39 (1.95, 2.94) | yes vs. no |
| Caffeine on DOB, n (%) | 136 (57%) | 177 (49%) | 1.19 (0.98, 1.45) | yes vs. no |
| Mechanical ventilation at 1 week of age, n (%) | 194 (81%) | 120 (34%) | 3.81 (2.89, 5.04) | yes vs. no |
| Days until birth weight regained, median (IQR)c | 8 (5-11) | 7 (5-10) | 1.15 (1.05, 1.25) | Per 7 day increase |
| Mean weight gain, g/day (SE)b | 21.4 (0.4) | 27.3 (0.4) | 0.90 (0.88, 0.91) | 1 g/d increase |
| Ever fed breast milk, n (%) | 215 (90%) | 309 (86%) | 1.21 (0.87, 1.70) | yes vs. no |
Abbreviations: BPD, bronchopulmonary dysplasia; IQR, interquartile range; DOB, day of birth; SE, standard error.
a
Among the 495 infants receiving enteral iron supplementation.
b
Results from mixed-effects linear model, with random intercept and slope for each infant.
c
N=594. Four infants died before birth weight regained.