The Long-Term Mortality Predictors in Hypertrophic Cardiomyopathy Patients with Low Risk of Sudden Cardiac Death

OBJECTIVE
Hypertrophic cardiomyopathy (HCM) is a common hereditary cardiac disorder. Clinical presentations in the Turkish population may differ from those observed in other countries. This study aimed to evaluate the relationship between the sudden cardiac death (SCD) risk score and long-term mortality in low-risk HCM patients and to identify predictors of long-term mortality. Additionally, it investigated the clinical characteristics and outcomes of HCM patients at a tertiary cardiology center.


METHOD
Between 2004 and 2021, a total of 340 HCM patients without implantable cardioverter defibrillators were followed at a single tertiary cardiology center in Türkiye. This was a retrospective study. The HCM Risk-SCD score was used to integrate demographic and clinical variables to estimate the predicted five-year risk of death. Patients with an HCM Risk-SCD score of less than 4% were divided into three equal tertiles, ranging from low to high SCD scores. These tertiles were then compared.


RESULTS
Our study identified older age [hazard ratio (HR) 95% confidence interval (CI): 1.048 (1.018-1.080)], a history of cerebrovascular accident [HR 95% CI: 3.675 (1.158-11.656)], and elevated neutrophil count [HR 95% CI: 1.450 (1.250-1.681)] as independent risk factors for long-term mortality in the cohort with HCM Risk-SCD < 4%. The receiver operating characteristic (ROC) curve demonstrated that the optimal HCM Risk-SCD threshold for predicting long-mortality in the overall study cohort was > 1.79, with 55% sensitivity and 55% specificity (area under the curve (AUC): 0.60, 95% CI: 0.52-0.69, P < 0.001). No statistically significant difference in long-term mortality was observed among the tertiles in the Kaplan-Meier analysis (P = 0.296).


CONCLUSION
Advanced age, cerebrovascular accident, and elevated neutrophil count are independent predictors of long-term mortality in patients with an HCM Risk-SCD score < 4%. Patients classified as low risk should undergo further evaluation using complementary tools to help prevent SCD.