Table 1.
Statistical summary of the clinical variables in the respiratory distress syndrome group and non–respiratory distress syndrome group.
| Data | RDSa group (n=10,041) | Non-RDS group (n=3046) | P valueb | ||||||
| Basic infant information | |||||||||
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Gender, n | >.99 | |||||||
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Male | 5165 | 1395 |
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Female | 4876 | 1651 |
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Birth weight (g), mean (SD) | 1022.01 (284.26) | 1269.24 (198.43) | <.001 | |||||
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Birth height (cm), mean (SD) | 35.81 (3.64) | 38.55 (2.75) | .45 | |||||
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Birth head circumference (cm), mean (SD) | 25.37 (2.44) | 27.62 (1.74) | <.001 | |||||
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Birthplace, n | .84 | |||||||
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In hospital | 9871 | 3009 |
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Transferred from another hospital after birth | 161 | 34 |
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Not in hospital | 9 | 3 |
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| Maternity history, mean (SD) | |||||||||
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Body temperature at the initial admission (°C) | 36.14 (0.63) | 36.30 (0.48) | <.001 | |||||
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Maternal age (years) | 33.27 (4.29) | 33.20 (4.09) | .78 | |||||
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Diabetes, n | .005 | |||||||
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No diabetes | 9041 | 2761 |
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Gestational diabetes mellitus | 857 | 255 |
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Overdiabetes mellitus | 143 | 30 |
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Hypertension, n | <.001 | |||||||
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No hypertension | 8083 | 2090 |
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Pregnancy-induced hypertension | 1718 | 896 |
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Chronic hypertension | 240 | 60 |
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Gravida, mean (SD) | 1.98 (1.22) | 1.84 (1.14) | <.001 | |||||
| Pregnancy/birth process | |||||||||
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Gestational age (weeks), mean (SD) | 27.56 (2.53) | 31.54 (2.36) | <.001 | |||||
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Amount of amniotic fluid, n | .93 | |||||||
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Normal | 8415 | 2553 |
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Oligohydramnios | 1452 | 492 |
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Hydramnios | 174 | 30 |
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Premature rupture of membrane, n | 3713 | 789 | .38 | |||||
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Antenatal steroid, n | 8764 | 2567 | .77 | |||||
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Delivery type (caesarean section), n | 7950 | 2510 | <.001 | |||||
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In vitro fertilization, n | 2455 | 769 | .07 | |||||
| Family history | |||||||||
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Parity, mean (SD) | 0.49 (0.73) | 0.40 (0.67) | <.001 | |||||
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Marriage, n | .07 | |||||||
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Married | 9862 | 3006 |
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Divorced | 6 | 3 |
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Single | 62 | 21 |
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Unmarried cohabitation | 111 | 16 |
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Multiple gestation, n | <.001 | |||||||
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Singleton | 6534 | 1756 |
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Twin | 3168 | 1070 |
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Triplet | 332 | 207 |
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Quadruplet or more | 7 | 13 |
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Birth order of multiple gestation, n | <.001 | |||||||
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First order | 1585 | 505 |
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Second order | 3612 | 1406 |
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Third order | 366 | 231 |
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Fourth order or more | 4 | 20 |
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| Resuscitation procedure, n | |||||||||
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Resuscitation at birth | 9634 | 2029 | <.001 | |||||
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Oxygen usage | 8854 | 1897 | .42 | |||||
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Positive pressure ventilation usage | 8830 | 1323 | <.001 | |||||
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Tracheal intubation | 7384 | 391 | .02 | |||||
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Cardiac compression | 523 | 32 | .02 | |||||
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Medication usage | 386 | 23 | .32 | |||||
| Test results at birth, mean (SD) | |||||||||
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1-min Apgar score | 4.32 (1.97) | 6.14 (1.79) | <.001 | |||||
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5-min Apgar score | 6.56 (1.86) | 8.02 (1.38) | <.001 | |||||
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Blood gas analysis (pH) | 7.26 (0.12) | 7.27 (0.09) | <.001 | |||||
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Blood gas analysis base excess | –5.39 (4.40) | –4.30 (3.41) | <.001 | |||||
aRDS: respiratory distress syndrome.
bP values are based on the 2-sided t test for means and a chi-square test for categorical variables. A 2-sided P value <.05 was considered significant.