Prognostic factors for cardiovascular-related mortality in pediatric hypertrophic cardiomyopathy: a retrospective cohort study with survival analysis and X-tile stratification

Objective: To identify prognostic factors associated with cardiovascular-related mortality in children with hypertrophic cardiomyopathy (HCM) and to explore outcome-oriented risk stratification using optimal cut-off values for continuous variables. Methods: This retrospective cohort study included 41 children diagnosed with HCM at The First Affiliated Hospital of Guangxi Medical University between January 1, 2013, and October 1, 2024. Baseline demographic characteristics, clinical manifestations, chest radiographic findings, electrocardiographic features, echocardiographic parameters, and serum biochemical indices were collected. Cardiovascular-related mortality was defined as the primary endpoint, with follow-up censored at the last clinical contact for patients lost to follow-up. Univariate Cox proportional hazards regression was performed to screen variables associated with mortality. Optimal cut-off values for continuous variables were determined using X-tile software, followed by Kaplan-Meier survival analysis and log-rank testing to compare survival differences between risk strata. Conclusion: This single-center real-world cohort suggests that cardiovascular-related mortality in pediatric HCM is more consistently associated with echocardiographic indicators reflecting left ventricular remodeling, hypertrophic burden, and systolic function, as well as biochemical markers of myocardial injury and metabolic stress. X-tile-based stratification of continuous variables provides intuitive and potentially actionable risk thresholds for intra-cohort follow-up and early risk warning. However, the generalizability of these thresholds requires validation in larger, multicenter cohorts.