Table 1 Comparison of clinical information of premature infants in the two groups
|  | Non-PNAC (n = 384) | PNAC (n = 81) | Z/T/χ 2 | P |
|---|---|---|---|---|
Mean gestational age at birth (weeks, \(\bar {x} \pm s\)) | 30.1 ± 1.8 | 29.1 ± 2.2 | 4.007 | <0.001 |
Mean birth weight (grams, \(\bar {x} \pm s\)) | 1273.6 ± 248.2 | 1074.7 ± 279.7 | 6.406 | <0.001 |
Male (n, %) | 198(51.6) | 47(58.0) | 1.121 | 0.290 |
Cesarean section (n, %) | 279(72.7) | 57(70.4) | 0.174 | 0.676 |
SGA (n, %) | 53(13.8) | 17(21.0) | 2.701 | 0.100 |
Five-minute Apgar scores ≤ 7 (n, %) | 37(9.6) | 9(11.1) | 0.163 | 0.686 |
Premature rupture of membranes > 18 h (n, %) | 59(15.4) | 11(13.6) | 0.167 | 0.683 |
Invasive mechanical ventilation (days)(mean, IQR) | 0.0(0.0,3.0) | 3.0(0.0,10.0) | -4.263 | <0.001 |
Non-invasive mechanical ventilation (days)(mean, IQR) | 18.0(8.0,31.0) | 33.0(15.0,49.8) | -4.220 | <0.001 |
Total duration of oxygen support (days)(mean, IQR) | 34.0(18.0,51.0) | 52.5(34.8,68.0) | -5.186 | <0.001 |
Maternal gestational diabetes (n, %) | 99(25.8) | 22(27.2) | 0.066 | 0.797 |
Maternal hypertension in pregnancy (n, %) | 117(30.5) | 27(33.3) | 0.257 | 0.612 |
Total hospital stay (days)(mean, IQR) | 47.0(38.0,60.0) | 67.0(53.0,82.0) | -6.573 | <0.001 |