Table 1 Demographics of extremely preterm (EP) infants and the mothers in outcome categories
Characteristics | Survivors (N = 1076) | Non-survivors (N = 975) | Total (N = 2051) | p-value | OR (95% CI) |
|---|---|---|---|---|---|
Characteristics of infants | |||||
GA (weeks), mean ± SD | 26.92 ± 0.86 | 26.41 ± 1.07 | 26.68 ± 1.00 | <0.001 | / |
BW (grams), mean ± SD | 976 ± 167 | 889 ± 180 | 935 ± 179 | <0.001 | / |
Gender (male), n (%) | 669 (62.2) | 586 (60.1) | 1255 (61.2) | >0.05 | 1.091 (0.913–1.303) |
Apgar score, n (%) | |||||
≤ 3 at 1 min | 95 (8.8) | 168 (17.2) | 263 (12.8) | <0.001 | 0.465 (0.356–0.608) |
4~7 at 1 min | 369 (34.3) | 391 (40.1) | 760 (37.1) | <0.01 | 0.780 (0.651–0.933) |
≤ 3 at 5 min | 9 (0.8) | 43 (4.4) | 52 (2.5) | <0.001 | 0.183 (0.089–0.377) |
4~7 at 5 min | 130 (12.1) | 214 (21.9) | 344 (16.8) | <0.001 | 0.489 (0.385–0.620) |
Surfactant therapy, n (%) | 900 (83.6) | 718 (73.6) | 1618 (78.9) | <0.001 | 1.830 (1.476–2.270) |
Surfactant therapy twice or more, n (%) | 155 (14.4) | 155 (15.9) | 310 (15.1) | >0.05 | 0.890 (0.699–1.134) |
Mechanical ventilation, n (%) | 816 (75.8) | 787 (80.7) | 1603 (78.2) | <0.01 | 0.750 (0.607–0.926) |
Days of mechanical ventilation (days), median (P25, P75) | 8.0 (2.0,22.0) | 2.3 (1.0,7.3) | 4.2 (1.0,15.0) | <0.001 | / |
Non-invasive ventilation, n (%) | 880 (81.8) | 240 (24.6) | 1120 (54.6) | <0.001 | 13.750 (11.117–17.007) |
Days of non-invasive ventilation (days), median (P25, P75) | 15.4 (6.0,26.0) | 3.1 (1.0,8.0) | 12.0 (4.0,23.0) | <0.001 | / |
Total days of oxygen therapy (days), median (P25, P75) | 42.7 (25.0,60.6) | 3.0 (1.0,9.8) | 19.5 (2.8,47.0) | <0.001 | / |
Length of hospital stay (days), median (P25, P75) | 71.0 (55.5,87.0) | 3.0 (1.0,10.0) | 35.0 (3.0,73.0) | <0.001 | / |
Characteristics of mothers | |||||
History of pregnancy problemsa, n (%) | 412 (38.3) | 349 (35.8) | 761 (37.1) | >0.05 | 1.113 (0.930–1.332) |
Age ≥ 35 years, n (%) | 238 (22.1) | 177 (18.2) | 415 (20.2) | <0.05 | 1.280 (1.030–1.591) |
Cesarean section, n (%) | 221 (20.5) | 172 (17.6) | 393 (19.2) | >0.05 | 1.207 (0.967–1.506) |
Twin/multiple pregnancy, n (%) | 392 (36.4) | 404 (41.4) | 796 (38.8) | <0.05 | 0.810 (0.678–0.968) |
Antenatal steroids, n (%) | 609 (56.6) | 367 (37.6) | 976 (47.6) | <0.001 | 2.160 (1.810–2.579) |
Dexamethasone ≥ 4 doses | 390 (36.2) | 204 (20.9) | 594 (29.0) | <0.001 | 2.149 (1.762–2.620) |
Dexamethasone 1~3 dose(s) | 219 (20.4) | 163 (16.7) | 382 (18.6) | <0.05 | 1.273 (1.017–1.593) |
Premature rupture of membranes, n (%) | 305 (28.3) | 194 (19.9) | 499 (24.3) | <0.001 | 1.593 (1.297–1.956) |
Infection in the middle trimester of pregnancy, n (%) | 82 (7.6) | 66 (6.8) | 148 (7.2) | >0.05 | 1.136 (0.812–1.590) |
Gestational diabetes mellitus, n (%) | 99 (9.2) | 88 (9.0) | 187 (9.1) | >0.05 | 1.021 (0.756–1.380) |
Pregnancy induced hypertension syndrome, n (%) | 71 (6.6) | 80 (8.2) | 151 (7.4) | >0.05 | 0.790 (0.567–1.102) |
Placental abruption/Placenta previa, n (%) | 72 (6.7) | 81 (8.3) | 153 (7.5) | >0.05 | 0.792 (0.569–1.101) |
Thyroid dysfunction, n (%) | 31 (2.9) | 22 (2.3) | 53 (2.6) | >0.05 | 1.285 (0.739–2.235) |
Cervical incompetence, n (%) | 28 (2.6) | 48 (4.9) | 76 (3.7) | <0.01 | 0.516 (0.321–0.829) |