Table 1.
Characteristics of the 2,040 premature infants included in the study.
| Characteristic (N = 2,040) | No. of infants at risk | Incidence rate of ROP (Yes vs. No)a | P-value |
|---|---|---|---|
| Gestational age, wkb | |||
| ≤ 28 | 70 (3.4) | 75.7% | <0.001 |
| 28–30 | 224 (11.0) | 43.3% | |
| 30–32 | 380 (18.6) | 15.3% | |
| >32 | 1,366 (67.0) | 2.4% | |
| Birth weight, gc | |||
| <1,000 | 74 (3.6) | 71.6% | <0.001 |
| 1,000–1,500 | 527 (25.8) | 27.9% | |
| ≥1,500 | 1,439 (70.5) | 2.8% | |
| NT-proBNP ≥ 25,000 ng/L | 293 (14.4) | 34.6 vs. 7.5% | <0.001 |
| NT-proBNP ≥ 20,000 ng/L | 342 (16.8) | 32.5 vs. 7.7% | <0.001 |
| NT-proBNP ≥ 15,000 ng/L | 434 (21.3) | 28.8 vs. 7.2% | <0.001 |
| NT-proBNP ≥ 10,000 ng/L | 601 (29.5) | 25.0 vs. 6.3% | <0.001 |
| Male | 1,123 (55.0) | 11.8 vs. 11.9% | 0.927 |
| Intrauterine asphyxia | 28 (1.4) | 28.6 vs. 11.6% | 0.013 |
| FGR | 148 (7.3) | 20.3 vs. 11.2% | 0.001 |
| PROM | 492 (24.1) | 13.6 vs. 11.2% | 0.155 |
| Cesarean section | 1,740 (85.3) | 10.2 vs. 21.0% | <0.001 |
| Multiple births | 515 (25.2) | 11.1 vs. 12.1% | 0.544 |
| Placenta previa | 440 (21.6) | 11.1 vs. 12.0% | 0.619 |
| Nuchal cord | 493 (24.2) | 11.8 vs. 11.8% | 0.969 |
| Amniotic fluid pollution | 349 (17.1) | 18. vs. 10.3% | <0.001 |
| Apgar 1 min, score | |||
| 1–3 | 49 (2.4) | 30.6% | <0.001 |
| 4–7 | 381 (18.7) | 24.9% | |
| 8–10 | 1,610 (78.9) | 8.1% | |
| Apgar 5 min, score | |||
| 1–3 | 10 (0.5) | 20.0% | <0.001 |
| 4–7 | 111 (5.4) | 38.7% | |
| 8–10 | 1,919 (94.1) | 10.2% | |
| Gestational hypertension | 698 (34.2) | 13.6 vs. 10.9% | 0.070 |
| GDM | 371 (18.2) | 11.9 vs. 11.8% | 0.976 |
| Embryo transfer | 363 (17.8) | 14.0 vs. 11.3% | 0.145 |
| Bad pregnancy or reproduction history | 283 (13.9) | 16.3 vs. 11.1% | 0.013 |
| Prenatal steroid | 568 (27.8) | 13.2 vs. 11.3% | 0.227 |
| Pulmonary surfactant therapy | 668 (32.7) | 28.1 vs. 3.9% | <0.001 |
| Invasive mechanical ventilation | 240 (11.8) | 45.8 vs. 7.3% | <0.001 |
| Non-invasive mechanical ventilation | 1,036 (50.8) | 11.2 vs. 12.5% | 0.381 |
| Nasal catheter oxygen inhalation | 35 (1.7) | 0.0 vs. 12.0% | 0.055 |
| Blood transfusion | 1,018 (49.9) | 21.7 vs. 2.0% | <0.001 |
| Weight gain rate, g/d | |||
| ≤ 12 | 138 (6.8) | 29.0% | <0.001 |
| 12–18 | 190 (9.3) | 31.6% | |
| >18 | 1,712 (83.9) | 8.2% | |
| Asphyxia | 369 (18.1) | 28.2 vs. 8.2% | <0.001 |
| Apnea | 92 (4.5) | 31.5 vs. 10.9% | <0.001 |
| RDS | 1,044 (51.2) | 20.6 vs. 2.6% | <0.001 |
| Cerebral hemorrhage | 1,256 (61.6) | 14.1 vs. 8.2% | <0.001 |
| Coagulation dysfunction | 1,060 (52.0) | 16.4 vs. 6.8% | <0.001 |
| BPD | 229 (11.2) | 27.1 vs. 7.1% | <0.001 |
| SGA | 420 (20.6) | 16.7 vs. 10.6% | 0.001 |
GDM, gestational diabetes mellitus; FGR, fetal growth restriction; PROM, premature rupture of membranes; SGA, small for gestational age; BPD, bronchopulmonary dysplasia; RDS, respiratory distress syndrome.
a
Incidence rate of ROP among infants when the risk factor is present (yes) vs. not present (no).
b
Median, Mean (SD; range), 33,33 (2; 25–37).
c
Median, Mean (SD; range), 1,800, 1,855 (575; 600–4,800).