266 - Risk Factors for Prematurity-Related Morbidity and Mortality in Neonates with Congenital Heart Disease

Publication Number: 4262.266

Giulia P. Lima, Boston Children's Hospital, Chestnut Hill, MA, United States; Philip T. Levy, Boston Children's Hospital, BROOKLINE, MA, United States; Isabella Zaniletti, IZ Statistics LLC, Tampa, FL, United States; Michael A.. Padula, Childrens Hospital of Philadelphia, Philadelphia, PA, United States; Theresa Grover, University of Colorado School of Medicine, Aurora, CO, United States; Jennifer A. Rumpel, University of Arkansas for Medical Sciences College of Medicine, Little Rock, AR, United States; Paulomi Chaudhry, Riley Hospital for Children at Indiana University Health, Indianapolis, IN, United States; Sharada H. Gowda, Riley Hospital for Children at Indiana University Health, Indianapolis, IN, United States; Karna Murthy, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, United States; Sarah Morton, Boston Children's Hospital, Boston, MA, United States

Background: Congenital heart disease (CHD) and prematurity are the leading causes of infant death in the United States during the first year of life. Although current evidence has quantified excess morbidity and mortality in preterm infants with CHD, we have a limited understanding of the key drivers.

Objective: To identify risk factors of in-hospital mortality and length of stay in preterm infants with CHD

Design/Methods: We performed a 15-year (2010-2024) retrospective cohort study of infants born < 35 weeks' gestational age (GA) with CHD using data from the Children's Hospitals Neonatal Consortium. The primary outcome was in-hospital mortality. The secondary outcome was postmenstrual age (PMA) at discharge, used as a proxy for length of stay (LOS), among survivors. CHD subtypes were congestive heart failure (CHF), compromised systemic output (CSO), or sustained cyanosis (SC). Univariable and multivariable generalized linear mixed models with hospital-level random intercepts were used, including a pre-specified GA-by-CHD subtype interaction. The Institutional Review Board at Boston Children's Hospital approved this study.

Results: Among 11,261 preterm infants with CHD, median GA was 30 weeks (IQR 27-33) and mortality was 13.7%. In multivariable analysis, the interaction between GA and CHD subtype was significant, with lower GA conferring decreased risk of mortality in the CHF subtype (27-29 vs 30-32 weeks GA, OR 0.69, p = 0.002). Mortality risk was highest in the CSO subtype (27%) compared to SC (15.5%) and CHF (11.2%). Referent to infants with CSO, those with SC or CHF had a nearly 4-fold decreased, independent odds of mortality, after adjusting for covariates (Table 1). Median PMA at discharge in this cohort was 42 weeks. Discharge occurred at earlier PMA for those born at 30-32 weeks' GA (OR 0.95, p < 0.001). Presence of a gastrostomy tube (OR 1.24, p< 0.001), urinary tract infection (OR 1.10, p < 0.001), and bloodstream infection (OR 1.09, p< 0.001) were each associated with increased duration of hospitalization by 10.2, 4.4, and 4 weeks, respectively (Table 2).

Conclusion(s): In this large multicenter cohort of contemporary preterm infants with CHD, largely non-modifiable risk factors were drivers of inpatient mortality. The identified determinants of LOS appear to have some modifiable components, even though PMA at discharge was largely driven by CHD subtype and extra-cardiac comorbidities. GA maturity was not associated with lower mortality in our cohort. Recognizing lesion-specific and comorbidity-related risks may enhance prenatal counseling and guide individualized postnatal care strategies.

Table 1. Multivariable Model of Risk Factors Associated with Mortality
GA, gestation age; NEC, necrotizing enterocolitis; CNS, central nervous system
Mortality rate of 13.7% (n=1542)

Table 2. Multivariable Model of Risk Factors Associated with PMA at Discharge in Survivors
GA, gestational age GU, genitourinary
N= 9,718