Social inequities impact infant mortality due to congenital heart disease.

Objectives: To evaluate how educational, economic, and racial residential segregation may impact congenital heart disease infant mortality (CHD-IM).

Study Design: This is a population-based US ecological study.

Methods: This study evaluated linked live birth-infant death files from the National Center for Health Statistics for live births from 2006 to 2018 with cause of death attributed to CHD. Maternal race and education data were obtained from the live birth-infant death files, and income data were obtained from the American Community Survey. A spatial social polarization measure termed the Index of Concentration at the Extremes (ICE) was calculated and split by quintiles for maternal education, household income, and race for all US counties (n = 3142). The lowest quintile represents counties with highest concentration of disadvantaged groups (income < $25K, non-Hispanic Black, no high school degree). Proximity to a pediatric cardiac center (PCC) was also analyzed in a categorical manner based on whether each county was in a metropolitan area with a US News and World Report top 50 ranked PCC, a lower ranked PCC, or not proximal to any PCC.

Results: Between 2006 and 2018, 17,489 infant deaths were due to CHD, an unadjusted CHD-IM of 0.33 deaths per 1000 live births. The risk of CHD-IM was 1.5 times greater among those in the lowest ICE-education quintile (0.41 [0.39-0.44] vs 0.28 deaths/1000 live births [0.27-0.29], P < 0.0001) and the lowest ICE-income quintile (0.44 [0.41-0.47] vs 0.29 [0.28-0.30], P < 0.0001) in comparison to those in the highest quintiles. CHD-IM increases with higher ICE-race value (counties with a higher concentration of non-Hispanic White mothers). However, after adjusting for proximity to a US News and World Report top 50 ranked PCC in the multivariable models, CHD-IM decreases with higher ICE-race value.

Conclusions: Counties with the highest concentration of lower-educated mothers and the highest concentration of low-income households were associated with higher rates of CHD-IM. Mortality as a function of race is more complicated and requires further investigation.