Mortality and Morbidity in Infants <34 Weeks' Gestation in 25 NICUs in China: A Prospective Cohort Study

Abstract

Objectives: To describe the rates and variability of mortality and morbidity of preterm infants born in China. Methods: This prospective cohort study included infants born at <34 weeks' gestation and admitted to 25 NICUs within 7 days of birth between May 1st, 2015 and April 30th, 2016. Infants were followed until death or NICU discharge. The primary outcome was a composite of mortality or any major morbidity (sepsis, necrotizing enterocolitis, intraventricular/periventricular leukomalacia, retinopathy of prematurity, and bronchopulmonary dysplasia) in infants who received complete care following medical advice. Secondary outcomes included rate of discharge against medical advice, mortality and individual morbidities. Results: Of the 8,065 infants, 6,852 (85%) received complete care and 1,213 (15%) were discharged against medical advice. Among infants who received complete care, the rate of the composite outcome was 27% (1,827/6,852), mortality 4% (248/6,852), sepsis 14% (990/6,852), necrotizing enterocolitis 3% (191/6,550), intraventricular hemorrhage/periventricular leukomalacia 7% (422/6,307), retinopathy of prematurity 2% (67/3,349), and bronchopulmonary dysplasia 9% (616/6,852). There were significant variations between NICUs for all outcomes. Conclusions: Discharged against medical advice, mortality, and morbidity rates for preterm infants <34 weeks' gestation are high in China with significant variations between NICUs.

Keywords: China; morbidity; mortality; outcome; preterm infants.

Figure 1

Locations of participating hospitals.

Figure 2

Variation by NICU of composite outcome of infants born at <34 weeks' gestation who received complete care. NICU Q (open diamond) was the reference center in all regression models. To calculate the adjusted odds ratio (aOR), the adjusted covariates were sex, gestational age, small for gestational age, Apgar score <3 at 5 min, TRIPS score on admission, inborn, cesarean, maternal hypertension, maternal diabetes, and antenatal steroids. Error bars indicate 95% confidence intervals (CI).

Figure 3

Variation by NICU of mortality and morbidity of infants born at <34 weeks' gestation who received complete care. The NICU with the median outcome rate was used as the reference site for the multi-regression model (open diamond). The adjusted covariates were sex, gestational age, small for gestational age, Apgar score <3 at 5 min, TRIPS score on admission, inborn, cesarean, maternal hypertension, maternal diabetes and antenatal steroids. Error bars indicate 95% confidence intervals. NICUs, neonatal intensive care units; aOR, adjusted odds ratios; NEC, necrotizing enterocolitis; IVH, intraventricular hemorrhage; PVL, periventricular leukomalacia; ROP, retinopathy of prematurity; BPD, bronchopulmonary dysplasia. ^aSepsis included both culture-proven sepsis and clinical sepsis. ^bIncluded all infants who survived 72 h. NEC was defined as NEC ≥ stage 2 according to Bell's criteria. ^cIncluded all infants with neuroimaging results. IVH was defined as IVH ≥ grade 3 according to Papile et al. or PVL. ^dIncluded all infants with eye examinations. ROP was defined as ≥ stage 3 according to international classification of ROP. ^eBPD was defined as requiring mechanical ventilation or oxygen dependency at 36 weeks' postmenstrual age or discharge.