Patterns, survival, and mortality predictors in children with down syndrome and congenital heart disease in resource-limited settings: a follow-up study

Abstract

Down syndrome (DS) is the most common chromosomal disorder associated with congenital heart disease (CHD). However, data on CHD patterns, survival, and mortality predictors among individuals with DS in developing countries remain limited. This study aimed to evaluate these features in children with DS. This hospital-based retrospective follow-up study included 460 children (≤ 18 years) with DS and CHD, followed at the Cardiac Center of Ethiopia between January 2014 and January 2025. Data were collected from April 1 to June 1, 2025. CHD patterns were described using frequencies and percentages, survival was analyzed with Kaplan–Meier curves, and mortality predictors were assessed using Cox proportional hazards models and Fisher’s exact test. The median age was 24 months (Interquartile Range (IQR) 6–48), with a female-to-male ratio of 1.45. Most children (70.4%) had a single CHD; atrioventricular septal defect (AVSD) was most common (33.3%), followed by ventricular septal defect (VSD, 21.9%) and patent ductus arteriosus (PDA, 18.8%). Overall survival was 95.5% at 5 years and 70.3% at 10 years. Survival differed by CHD complexity: complex CHDs had 5- and 10-year survival of 90.6% and 56.2%, respectively, versus 100% and 88.8% for non-complex CHDs (p < 0.001). Mortality was significantly higher in children without surgery (p = 0.04). Independent predictors of mortality included weight-for-age below the 5th percentile (AHR 3.01; 95% CI 1.8–6.4; p = 0.02), hypothyroidism (AHR 1.2; 95% CI 1.02–5.1; p = 0.001), complex CHDs (AHR 3.2; 95% CI 1.1–4.2; p < 0.001), and pulmonary hypertension (AHR 1.1; 95% CI 1.1–3.8; p = 0.03). Most children and adolescents with DS and CHD had simple, isolated defects such as AVSD and VSD. Survival differed significantly between simple and complex CHDs and between children who underwent surgery and not. Independent mortality predictors included underweight status, pulmonary hypertension, hypothyroidism, and complex CHDs, emphasizing the need for comprehensive management, including nutritional support, risk stratification, and timely surgical intervention.