Bayesian Bivariate Survival Analysis of Oxygen Saturation and Pulse Rate as Predictors of Survival Risk in Pediatric Cardiac Patients

Pediatric heart disease is a major contributor to illness and death worldwide, with a disproportionately high burden in low-resource settings such as Ethiopia. To investigate the clinical and demographic factors associated with survival in children diagnosed with cardiac disease. A retrospective cohort study was used among children (<18 years) at the Children's Heart Fund of Ethiopia. Longitudinal SpO₂ and pulse rate were modeled with survival time using joint modeling. The two-year survival probability was 90.28%, with a 9.28% mortality rate. Pulmonary hypertension, type of cardiac disease, atrial fibrillation, BMI, and ejection fraction were significant predictors of mortality. Pulmonary hypertension and chamber enlargement reduced survival and lowered SpO₂, while congenital heart disease showed better longitudinal improvement. Anemia was associated with declining SpO₂ and shorter survival, whereas higher BMI improved survival. Joint modeling revealed that both longitudinal measures and baseline clinical factors significantly affect survival. These findings support early monitoring, and timely interventions to improve outcomes in resource-limited pediatric cardiac populations.