Table 1.
Demographic and Clinical Characteristics of Infants According to Study Site
| Characteristic | Study Sitea | P Valuesb | |||
|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | ||
| Subjects | 443 | 341 | 204 | 332 | .98 |
| Gestational age (mean [SD]) (wk) | 32 (5) | 32 (3) | 36 (3) | 31 (4) | <.01 |
| Birth weight (mean [SD]) (g)c | 1814 (996) | 1692 (658) | 2575 (779) | 1587 (728) | <.01 |
| Birth weight strata(n [row %])c | <.01 | ||||
| ≥2500 g | 129 (29.1) | 32 (9.4) | 116 (56.9) | 31 (9.3) | |
| 1500–2499 g | 94 (21.2) | 169 (49.6) | 67 (32.8) | 132 (39.8) | |
| 1000–1499 g | 104 (23.5) | 98 (28.7) | 15 (7.4) | 103 (31.0) | |
| <1000 g | 116 (26.2) | 42 (12.3) | 6 (2.9) | 66 (19.9) | |
| Sex | .06 | ||||
| Male | 253 (57.1) | 169 (49.6) | 98 (48.0) | 185 (55.7) | |
| Female | 190 (42.9) | 172 (50.4) | 106 (52.0) | 147 (44.3) | |
| Race | <.01 | ||||
| White | 210 (47.4) | 118 (34.6) | 106 (52.0) | 200 (60.3) | |
| Black | 41 (9.3) | 23 (6.7) | 16 (7.8) | 114 (34.3) | |
| Otherd | 182 (41.1) | 44 (12.9) | 81 (39.7) | 10 (3.0) | |
| Unknown | 10 (2.2) | 156 (45.8) | 1 (0.5) | 8 (2.4) | |
| Ethnicity | <.01 | ||||
| Hispanic | 105 (23.7) | 14 (4.1) | 11 (5.4) | 15 (4.5) | |
| Non-Hispanic | 166 (37.5) | 179 (52.5) | 130 (63.7) | 310 (93.4) | |
| Unknown | 172 (38.8) | 148 (43.4) | 63 (30.9) | 7 (2.1) | |
| Length of stay (mean [SD]) (days) | 47 (36) | 45 (38) | 51 (47) | 44 (30) | .50 |
| Patient-days | 20 695 | 15 229 | 10 505 | 14 644 | .98 |
Abbreviation: SD, standard deviation.
aData are numbers (column percent) unless otherwise indicated.
b P values are reported for differences according to site using the χ2 test for categorical variables and the Wilcoxon rank-sum test for continuous variables.
cBirth weight was unavailable for 1 infant.
dIncludes Asian, Native Hawaiian, other Pacific Islander, and other.