Zacharias Mandalenakis

Background Increasing survival among patients with congenital heart disease (CHD) has recently been reported. However, the impact of Down syndrome (DS) in patients with CHD is still debated. We aimed to estimate survival in patients with CHD with versus without DS compared with matched controls from the general population without CHD or DS. Methods and Results We linked data from Swedish health registries to identify patients with CHD born between 1970 and 2017. Data from the Total Population Register were used to match each patient with CHD by sex and birth year with 8 controls without CHD or DS. A Cox proportional regression model was used to estimate mortality risk, and Kaplan–Meier curves were analyzed for the survival analysis. We identified 3285 patients with CHD‐DS, 64 529 patients with CHD without DS, and 26 128 matched controls. The mortality risk was 25.1 times higher (95% CI, 21.3–29.5) in patients with CHD‐DS versus controls. The mortality rate was 2 times higher (95% CI, 1.94–2.31) for patients with CHD with versus without DS. Lower mortality was found during the second versus first birth periods in patients with CHD‐DS compared with controls; hazard ratio: 46.8 (95% CI, 29.5–74.0) and 17.7 (95% CI, 12.8–24.42) in those born between 1970 and 1989 versus 1990 and 2017, respectively. Conclusions In this retrospective cohort study, the mortality risk among patients with CHD‐DS was 25 times higher compared with matched controls and 2 times higher compared with patients with CHD without DS. Survival was higher in patients with CHD‐DS born after versus before 1990, coinciding with the modern era of congenital heart care.