Association between Neonatal Outcomes and Admission Hypothermia among Very Preterm Infants in Chinese Neonatal Intensive Care Units: A Multicenter Cohort Study

Objective We aimed to investigate the relationship between admission hypothermia and outcomes among very preterm infants (VPIs) in neonatal intensive care units (NICUs) in China. We also investigated the frequency of hypothermia in VPIs in China and the variation in hypothermia across Chinese Neonatal Network (CHNN) sites. Study Design This retrospective cohort study enrolled infants with 240/7 to 316/7 weeks of gestation with an admission body temperature ≤37.5 °C who were admitted to CHNN-participating NICUs between January 1 and December 31, 2019. Results A total of 5,913 VPIs were included in this study, of which 4,075 (68.9%) had hypothermia (<36.5 °C) at admission. The incidence of admission hypothermia varied widely across CHNN sites (9–100%). Lower gestational age (GA), lower birth weight, antenatal steroid administration, multiple births, small for GA, Apgar scores <7 at the 5th minute, and intensive resuscitation were significantly associated with admission hypothermia. Compared with infants with normothermia (36.5–37.5 °C), the adjusted odds ratios (ORs) for composite outcome among infants with admission hypothermia <35.5 °C increased to 1.47 (95% confidence interval CI, 1.15–1.88). The adjusted ORs for mortality among infants with admission hypothermia (36.0–36.4 and <35.5 °C) increased to 1.41 (95% CI, 1.09–1.83) and 1.93 (95% CI, 1.31–2.85), respectively. Admission hypothermia was associated with a higher likelihood of bronchopulmonary dysplasia, but was not associated with necrotizing enterocolitis ≥stage II, severe intraventricular hemorrhage, cystic periventricular leukomalacia, severe retinopathy of prematurity, or sepsis. Conclusion Admission hypothermia remains a common problem for VPIs in a large cohort in China and is associated with adverse outcomes. Continuous quality improvement of admission hypothermia in the future may result in a substantial improvement in the outcomes of VPIs in China. Key Points