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

## TL;DR

This study examines how treatment and outcomes for neonatal brain injury in California changed between 2010 and 2019.

## Contribution

The study provides new insights into the use and effectiveness of therapeutic hypothermia for mild HIE over time.

## Key findings

- The incidence of HIE in California increased from 0.5 to 1.5 per 1,000 births between 2010 and 2018.
- Use of therapeutic hypothermia for mild HIE increased after 2015, but outcomes did not improve significantly.

## Abstract

Evaluate the changes in management and outcomes of Californian infants with hypoxic ischemic encephalopathy (HIE).

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.

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.

Significantly more infants with mild HIE received TH since 2015 in California, but no difference in outcomes was found for these patients.