Table 2. Factors affecting the length of stay of surviving preterm infants in neonatal intensive care units in Shenzhen, China.
Using generalized linear models (GLMs) with gamma distribution to determine the association between perinatal factors and neonatal complications with length of stay (LOS).
| Factors | Model 1 | Model 2 | Model 3 | Model 4 |
|---|---|---|---|---|
| RR (95% CI) | RR (95% CI) | RR (95% CI) | RR (95% CI) | |
| Maternal characteristics | ||||
| Maternal age | 1.00 (0.99, 1.01) | |||
| Primigravida | 1.07 (1.01, 1.14) | 1.01 (0.98, 1.04) | 1.00 (0.97, 1.04) | |
| Maternal hypertension | 1.47 (1.35, 1.59) | 1.12 (1.07, 1.17) | 1.12 (1.07, 1.17) | |
| Maternal diabetes | 1.01 (0.94, 1.08) | |||
| GBS infection | 0.94 (0.82, 1.09) | |||
| Antenatal corticosteroids | 1.91 (1.79, 2.02) | 1.12 (1.09, 1.16) | 1.13 (1.09, 1.17) | |
| cesarean section | 1.07 (0.99, 1.14) | |||
| PROM ≥ 18 h | 1.25 (1.14, 1.36) | 1.03 (0.99, 1.08) | 1.03 (0,98, 1.08) | |
| Infant characteristics | ||||
| GA(wk) | ||||
| <28 | Reference | Reference | Reference | |
| 28–31+6 | 0.59 (0.53, 0.67) | 0.79 (0.70, 0.90) | 0.83 (0.72, 0.95) | |
| 32–33+6 | 0.30 (0.26, 0.33) | 0.59 (0.51, 0.69) | 0.62 (0.53, 0.74) | |
| 34–36+6 | 0.11 (0.10, 0.13) | 0.31 (0.26, 0.36) | 0.32 (0.27, 0.38) | |
| Birth weight (g) | ||||
| <1,000 | Reference | Reference | Reference | |
| 1,000–1,249 | 0.73 (0.63, 0.84) | 0.93 (0.81,1.05) | 1.02 (0.89, 1.17) | |
| 1,250–1,499 | 0.54 (0.47, 0.62) | 0.80 (0.70, 0.92) | 0.91 (0.79, 1.05) | |
| 1,500–2,499 | 0.19 (0.17, 0.21) | 0.56 (0.49, 0.65) | 0.65 (0.56, 0.76) | |
| ≥ 2,500 | 0.09 (0.08, 0.10) | 0.38 (0.33, 0.45) | 0.46 (0.39, 0.54) | |
| SGA | 1.41 (1.28, 1.56) | 1.19 (1.12, 1.26) | 1.13 (1.07, 1.20) | |
| Male | 0.92 (0.86, 0.97) | 1.00 (0.97, 1.03) | 0.99 (0.97, 1.03) | |
| Multiple birth | 1.12 (1.05, 1.2) | 0.99 (0.96, 1.03) | 0.99 (0.96, 1.03) | |
| Apgar score ≤ 7 at 1 min | 2.90 (2.56, 3.28) | 1.1 (1.02, 1.19) | 1.08 (1.005, 1.17) | |
| Apgar score ≤ 7 at 5 min | 2.99 (2.26, 3.97) | 1.04 (0.89, 1.21) | 1.08 (0.92, 1.28) | |
| surfactant use | 3.52 (3.27, 3.79) | 1.23 (1.17, 1.30) | 1.22 (1.15, 1.29) | |
| Major infant morbidities | ||||
| Nosocomial infection | 2.32 (2.10, 2.57) | 1.36 (1.23, 1.49) | 0.99 (0.94, 1.06) | |
| IVH grade III and above or cPVL | 2.64 (1.95, 3.58) | 1.56 (1.19, 2.02) | 1.07 (0.91, 1.25) | |
| NEC ≥ stage II | 2.72 (1.87, 3.95) | 1.94 (1.41, 2.67) | 1.2 (0.99, 1.46) | |
| BPD | 4.90 (4.29, 5.59) | 3.78 (3.31, 4.32) | 1.13 (1.02, 1.26) | |
| Severe ROP | 4.82 (3.22, 7.22) | 1.47 (1.01, 2.12) | 1.26(1.00, 1.57) | |
| Sepsis | 3.23 (2.68, 3.90) | 1.88 (1.59, 2.23) | 1.28 (1.16, 1.42) | |
| EUGR | 1.47 (1.37, 1.57) | 1.38 (1.30, 1.47) | 1.09 (1.04, 1.14) |
Notes.
GBS, Group B Streptococcus; PROM, premature rupture of membranes; LOS, length of stay; GA gestational age; SGA, small for gestational age; IVH intraventricular hemorrhage, cPVL, cystic periventricular leukomalacia; NEC, necrotizing enterocolitis; BPD, bronchopulmonary dysplasia, ROP, retinopathy of prematurity; EUGR, extrauterine growth restriction; RR, relative risk. Model 1: Crude. Model 2: Adjust: primigravida, maternal hypertension, antenatal corticosteroids, gestational age, birth weight, small for gestational age, infant sex, multiple birth, surfactant use, Apgar score ≤ 7 at 1 min, Apgar score ≤ 7 at 5 min, and preterm rupture of membranes ≥ 18 h. Model 3: Adjust: nosocomial infections, IVH grade III and above or cPVL, NEC ≥ stage II, BPD, severe ROP, sepsis, and EUGR. Model 4: Adjust Model 2 plus Model 3. Significant results are in bold.