Changes in the Treatment and Outcomes of Different Severities of Neonatal Hypoxic Ischemic Encephalopathy in California: A Retrospective Cohort Study

Abstract Objective: Evaluate the changes in management and outcomes of Californian infants with hypoxic ischemic encephalopathy (HIE). Study Design: Infants with HIE were identified from a California administrative birth cohort using ICD codes and divided into two epochs, Epoch 1 (2010–2015) and Epoch 2 (2016–2019). Risk ratios (RR) for therapeutic hypothermia (TH) in each epoch and their outcomes were calculated using log-linear regression. Results: In this cohort, 4779 infants with HIE were identified. Incidence of HIE in California increased yearly from 0.5/1,000 California births to a peak of 1.5/1,000 births in 2018. The use of TH in infants with mild HIE increased in Epoch 2 compared to Epoch 1. There was no significant difference in outcomes between epochs for infants with mild HIE that received TH. Conclusion: Significantly more infants with mild HIE received TH since 2015 in California, but no difference in outcomes was found for these patients.