Patterns of cardiac diseases and risk factors forin-hospital mortality among children admitted to Mulago National Referral Hospital

Abstract

Background: Paediatric cardiac diseases, including congenital and acquired heart conditions, are a major cause of morbidity and mortality in low-resource settings such as Uganda. Despite the dual burden of congenital heart disease (CHD) and preventable acquired conditions like rheumatic heart disease, local evidence on disease patterns and determinants of in-hospital mortality remains limited. Objective: To describe the patterns of cardiac diseases, estimate the in-hospital mortality, and identify risk factors for mortality among children admitted to Mulago National Referral Hospital. Methods: A retrospective cohort study was conducted using medical records of children aged 0–17 years admitted to the cardiopulmonary ward (Firm C) with confirmed cardiac disease from January 2015 to January 2025. Demographic, clinical, laboratory, and echocardiographic data were extracted. Disease patterns were summarized descriptively. In-hospital mortality was expressed as a proportion and incidence density with 95% confidence intervals (CI). Cox proportional hazards regression and Kaplan-Meier curves were used for survival analysis. Results: A total of 521 children were included, with a mean age was 3.0 ± 4.2 years; 41.8% were infants aged 1-12 months and 50.3% were male. Congenital heart disease accounted for 81.6% of admissions, predominantly ventricular septal defect (32.2%), tetralogy of Fallot (17.1%), and atrial septal defect (11.9%). Acquired heart disease comprised 18.4% of admissions, mainly rheumatic heart disease (8.8%) and dilated cardiomyopathy (5.4%). The overall in-hospital mortality was 21.1% (110/521; 95% CI: 17.6–24.9). The incidence density of mortality was 25.2 deaths per 1000 persondays (95% CI 20.7-30.4), with median hospital stay of 6.0 days (IQR: 3.0–11.0). Independent predictors of mortality were malnutrition (aHR 2.38, 95% CI: 1.28-4.42), heart failure (aHR 2.61, 95% CI: 1.41-4.83), severe pneumonia (aHR 2.89, 95% CI: 1.48-5.64), and lower platelet count (aHR 0.75 per 100×10⁹/L increase, 95% CI: 0.60-0.94). Cardiac diagnosis was not independently associated with mortality. Conclusion: Children admitted with cardiac disease at Mulago National Referral Hospital experience substantial in-hospital mortality. Mortality was primarily associated with potentially modifiable clinical conditions including malnutrition, heart failure and severe pneumonia rather than the underlying cardiac diagnosis itself. Strengthening early recognition and integrated management of these comorbidities offers an immediate opportunity to improve inpatient survival even within current resource constraints. Keywords: congenital heart disease, acquired heart disease, rheumatic heart disease, paediatric cardiology, mortality, heart failure, Uganda.