Survival of Children With Critical Congenital Heart Defects in the National Birth Defects Prevention Study

Background

Critical congenital heart defects (CCHDs) are associated with considerable morbidity and mortality. This study estimated survival of children with nonsyndromic CCHDs and evaluated relationships between exposures of interest and survival by CCHD severity (univentricular or biventricular function).

Methods

This analysis included 4380 infants with CCHDs (cases) born during 1999–2011 and enrolled in the National Birth Defects Prevention Study, a multisite, population-based case–control study of major birth defects. Cases were linked to state death files. Nonparametric Kaplan–Meier survival functions were used to estimate 1- and 5-year survival probabilities overall and by severity group (univentricular/biventricular) stratified by demographic and clinical exposure variables of interest. The log-rank test was used to determine whether stratified survival curves were equivalent. Survival and 95% confidence intervals (CIs) were also estimated using Cox proportional hazards modeling adjusted for maternal age, education, race/ethnicity, study site, and birth year.

Results

One- and five-year survival rates were 85.8% (CI 84.7–86.8) and 83.7% (CI 82.5–84.9), respectively. Univentricular 5-year survival was lower than biventricular case survival [65.3% (CI 61.7–68.5) vs. 89.0% (CI 87.8–90.1; p < 0.001)]. Clinical factors (e.g. preterm birth, low birthweight, and complex/multiple defects) were associated with lower survival in each severity group. Sociodemographic factors (non-Hispanic Black race/ethnicity, <high school education, smoking, and lower household income) were only associated with survival among biventricular cases.

Conclusions

Mortality among children with CCHDs occurred primarily in the first year of life. Survival was lower for those with univentricular defects, and social determinants of health were most important in predicting survival for those with biventricular defects.