TABLE 2

Characteristics of Infants Included in the Study

VariableEarly-Caffeine Group (N = 1545)Late-Caffeine Group (N = 563)P
Maternal characteristics
 Maternal ethnicity, n (%).49
  White895 (67.6)315 (68.9)
  African American110 (8.3)43 (9.4)
  Other319 (24.1)99 (21.7)
 Maternal education, n (%).89
  Less than high school164 (11.5)52 (10.5)
  Completed high school243 (17.0)81 (16.3)
  Some college254 (17.8)90 (18.1)
  College and above765 (53.7)274 (55.1)
 Antenatal steroids, n (%)1386 (91.0)477 (89.0).17
 Multiples, n (%)446 (28.9)150 (26.6).32
 Cesarean delivery, n (%)895 (58.0)328 (58.6).83
Neonatal characteristics
 GA, wk, median (IQR)27 (26–28)26 (25–27)<.01
  ≤24, n (%)117 (7.6)105 (18.7)<.01
  25–28, n (%)1428 (92.4)458 (81.3)
 Birth wt, g, median (IQR)950 (790–1110)850 (700–1040)<.01
 Female sex, n (%)718 (46.5)279 (49.6).20
 Apgar score at 5 min, median (IQR)7 (6–8)7 (5–8)<.01
 SNAP-II score, median (IQR)12 (7–18)16 (9–29)<.01
 Small for GA, n (%)101 (6.6)54 (9.6).02
 Intubation at birth, n (%)621 (41.9)236 (42.7).75
 Surfactant, n (%)1129 (89.3)441 (89.8).76
 Duration of caffeine, d, median (IQR)51 (38–65)49 (31–64).01
 Postnatal steroids, n (%)327 (21.2)242 (43.0)<.01
 Air leak syndrome, n (%)49 (3.2)38 (6.8)<.01
  • IQR, interquartile range.