Table 2:

Infant and maternal characteristics and process measures

CharacteristicStudy year; no. (%) of infants*p value
Baseline
n = 1422
Year 1
n = 1611
Year 2
n = 1508
Year 3
n = 1485
OverallBaseline v. yr 3
Sex, male778 (55)897 (56)799 (53)841 (57)0.20.3
Gestational age (GA)< 0.001< 0.001
 220 to 256 wk§403 (28)519 (32)477 (32)534 (36)
 260 to 286 wk§1019 (72)1092 (68)1031 (68)951 (64)
 Mean ± SD, wk26.3 ± 1.526.2 ± 1.526.2 ± 1.526.1 ± 1.5< 0.001< 0.001
Birth weight, g, mean ± SD947 ± 274920 ± 238919 ± 246919 ± 2560.0040.004
Small for GA130 (9)133 (8)121 (8)19 (8)0.60.3
Outborn304 (21)304 (19)284 (19)283 (19)0.20.1
Apgar score < 7 at 5 min543 (38)618 (38)628 (42)675 (45)< 0.001< 0.001
SNAP-II score > 20393 (28)475 (29)457 (30)476 (32)0.050.006
Singleton1012 (71)1153 (72)1090 (72)1089 (73)0.60.2
Cesarean birth801 (56)910 (56)842 (56)833 (56)0.90.6
Maternal hypertension**203/1391 (15)245/1560 (16)238/1483 (16)211/1436 (15)0.60.9
Maternal diabetes mellitus**96/1389 (7)106/1531 (7)116/1454 (8)108/1415 (8)0.60.5
Antenatal steroids**1151/1374 (84)1358/1562 (87)1264/1465 (86)1258/1458 (86)0.080.06
Intrapartum magnesium sulphate**NA194/1133 (17)320/1437 (22)582/1419 (41)< 0.001NA
Surfactant use1115 (78)1271 (79)1182 (78)1126 (76)0.20.1
Age at first surfactant, median (IQR), min31 (15–93)39 (17–161)44 (19–201)46 (20–212)< 0.0010.02
Mechanical ventilation, any time1260 (89)1391 (86)1268 (84)1228 (83)< 0.001< 0.001
  • Note: EPIQ = Evidence-based Practice for Improving Quality, IQR = interquartile range, NA = not available, SD = standard deviation, SNAP-II = Score for Neonatal Acute Physiology, version II (a measure of severity of illness on admission to neonatal intensive care unit; scores range from 0 to 115, with higher scores indicating increasing sickness).21

  • * Except where indicated otherwise.

  • Calculated using χ2 test for categorical variables and F test or Wilcoxon rank-sum test, as appropriate, for continuous variables.

  • Based on comparison between baseline and year 3.

  • § Superscript 0 and 6 denote number of days in addition to weeks of gestation.

  • Born at a hospital other than the institution that housed the admitting neonatal intensive care unit.

  • ** Data missing for some infants; denominators used to calculate percentages (shown in these rows) reflect available data.