Abstract 9959: Narrowing the Survival Gap: Trends in Survival in Individuals with Down Syndrome with and without Congenital Heart Defects Born 1979 - 2018

Abstract

Introduction: Congenital heart defects (CHD) affect nearly 50% of children born with Down syndrome (DS) and have been shown to affect both early (<1 year) and late mortality. In the non-DS population, survival with CHD has improved greatly over the last 40 years. We aim to evaluate if these changes have narrowed the survival gap between those with DS + CHD and those with DS alone over recent decades. Methods: Individuals with DS born in metropolitan Atlanta between 1979 and 2018 were identified through the Metropolitan Atlanta Congenital Defects Program, a population-based surveillance system maintained by the Centers for Disease Control and Prevention. Survival analysis was performed to evaluate predictors of mortality for those with DS + CHD and DS alone. Results: Cohort included 1,668 individuals with DS, 764 individuals of whom had a CHD. There were 150 deaths at a median age of 0.4 years (interquartile range (IQR) 0.1 - 4.5 years). In a multivariable model evaluating survival through 10 years, CHD, birthweight <2500g, birth before 2000, and maternal Black race were associated with mortality. Ten-year survival in DS + CHD improved steadily from the 1980s to 2010s (82% to 93%, p=0.01) but remained stable (96% to 95%, p=0.97) in those with DS alone; presence of CHD was not significantly associated with mortality for those born in the most recent decade (HR 1.65 [95% CI 0.60 - 4.51], Figure). In multivariable analysis conditioning on surviving to 1 year, presence of CHD (HR 3.04 [95% CI 1.79-5.18]) remained significantly associated with long-term mortality. Conclusions: Early survival among children with DS + CHD has significantly improved over the last 4 decades, such that the survival gap between those with DS + CHD and those with DS alone has disappeared in the most recent decade. It remains to be seen whether these improvements will translate into improved long-term survival; CHD continues to be a risk factor for late mortality for those born in earlier decades.