Neighborhood deprivation is associated with NICU mortality for extremely premature infants: A 4-NICU study

Abstract

Importance: Socioeconomic status impacts pregnancy outcomes and child development after NICU discharge for infants born prematurely, but has not been well studied for outcomes during the NICU stay. The Area Deprivation Index (ADI) is a validated measure of neighborhood disadvantage that uses Census data on income, education, employment, and housing quality. Objective: In NICUs in different US regions, determine if ADI predicts NICU mortality and morbidity in extremely premature infants. Design: We conducted a retrospective cohort study. Setting: Four level IV neonatal intensive care units (NICU) in different US geographic regions: Northeast, Mid-Atlantic, Midwest, and South. Participants: Non-Hispanic White and Black extremely premature infants (gestational age <29 weeks) and admitted to a study NICU from 2012-2020. Exposures: ADI, race, BW, sex, and outborn status (admitted after transfer from an outside birth hospital). Main Outcomes and Measures: We converted addresses to census blocks, identified by 12-digit Federal Information Processing Series (FIPS) codes, to link residences to the national ADI percentile of study participants. We analyzed the relationship between ADI and NICU mortality using Bayesian logistic regression adjusted for race, BW, outborn status, and sex. Predictors were considered significant if the 95% Credible Intervals excluded zero. We also analyzed the effect of ADI on NICU morbidities of late-onset sepsis, necrotizing enterocolitis, and severe intraventricular hemorrhage. Results: We studied 2,765 infants. In univariate analysis, infants with higher ADI were more likely to be Black, suffer from short-term morbidities, and die before NICU discharge. ADI did not correlate with BW (r = -0.05) or sex. Black infants also had higher mortality and lower BW. In a multivariable model, lower BW, higher ADI, and male sex were statistically significant risk factors, while Black race and outborn status were not. Using these methods, ADI was also identified as a risk factor for NICU morbidities. Conclusions and Relevance: Among extremely preterm infants admitted to four NICUs in different US geographic regions, ADI was a risk factor for mortality and morbidity after adjusting for multiple covariates. These findings have implications for public health measures to improve prenatal and NICU care for patients from disadvantaged areas.