Risk Factors for Mortality and Age at Discharge in Infants with Congenital Heart Disease Born Preterm

To evaluate risk factors for mortality and discharge timing in preterm infants born before 35 weeks of gestational age with congenital heart disease (CHD).

This was a retrospective cohort study in which we used Children's Hospitals Neonatal Consortium data collected from 2010 to 2024. Infants <35 weeks of gestational age with CHD were included. Primary and secondary outcomes were in-hospital mortality and postmenstrual age at discharge. CHD subtypes were categorized as compromised systemic output, sustained cyanosis, or congestive heart failure. Multivariable generalized linear mixed models were used.

Among 11 261 infants born preterm with CHD, mortality was 13.7%. Significant interactions between CHD subtype and gestational age were observed. Among infants with congestive heart failure, those 30-32 weeks of gestational age had greater mortality compared with <27 weeks of gestational age (aOR 1.46, 95% CI 1.06-2.02, P = .012), and those 27-29 weeks of gestational age had lower mortality odds compared with 30-32 weeks (aOR 0.69, 95% CI 0.52-0.90, P = .002). Surgical necrotizing enterocolitis, delivery room intubation, and trisomy 21 were the strongest mortality predictors (aOR 3.12, 2.69 and 2.27, respectively; all P < .001). Greater gestational age was associated with earlier postmenstrual age at discharge (-2.4 weeks for 30-32 weeks of gestational age vs <27 weeks of gestational age; P < .001).

Short-term outcomes vary by CHD subtype and comorbidities. Older gestational age was unrelated to inpatient mortality. Potentially modifiable factors such as necrotizing enterocolitis and infections could inform care. Future work incorporating prenatal decisions and surgical timing is needed.