Therapeutic hypothermia and in-hospital mortality in 35-week infants with encephalopathy

Objectives Therapeutic hypothermia (TH) improves outcomes in infants ≥36 weeks with HIE, although safety at 35weeks remains uncertain. We compared TH utilization and associated outcomes in 35- versus 36-week infants with HIE. Study design Using the 2016–2022 National Inpatient Sample, we identified 35- and 36-week infants with HIE. The primary outcome was in-hospital mortality; secondary outcomes included coagulopathy and other complications. Logistic regression adjusted for covariates; Cochran–Armitage tested trends in TH use. Results Among 1,397,680 infants, HIE occurred in 2354 (0.48%) at 35 weeks and 3972 (0.44%) at 36 weeks; in-hospital mortality was similar (9.98% vs 9.99%). TH was less frequently used at 35 weeks (19.8% vs 22.4%) but increased over time ( p < 0.001). 35-week treated infants had higher unadjusted in-hospital mortality (10.3% vs 6.8%) and coagulopathy (28.7% vs 18.4%); adjusted in-hospital mortality did not differ. Conclusion TH use at 35 weeks is increasing that was not associated with differences in in-hospital mortality. Prospective studies are needed to define its role.