Establishment of a Risk Prediction Model for Thrombotic Events in Chinese Patients with Hypertrophic Cardiomyopathy

Background Thrombotic events are a major complication of hypertrophic cardiomyopathy (HCM). There are only two available risk prediction models for thrombotic events, HCM Risk-CVA score and French HCM score developed by foreign scholars, yet the former one has been found to have limited predictive value in Chinese HCM patients. Objective To develop a risk prediction model for thrombotic events in Chinese patients with HCM. Methods A retrospective cohort study design was used. Five hundred and thirty-seven HCM patients who admitted to West China Hospital of Sichuan University from 2010 to 2018 were recruited. Post-discharge health status was collected by use of telephone follow-up or checking the treatment status recorded in the electronic medical record system once every 6 to 12 months until a composite thrombotic event (defined as the endpoint event) or death occurred or the determined thrombotic risk assessment day of this study (2019-12-31). Univariate and multvariate Cox regression analyses were applied to build a thrombotic risk prediction model, and its internal validation was tested in a resample using the bootstrapping technique. Results Due to data missing, 24 cases were excluded, and the other 513 cases were finally included. During a median follow-up of 4.2 years (IQR: 1.3-6.2 years), thrombotic events occurred in 42 cases (8.18%), with an annual morbidity rate of 2.10%〔95%CI (1.47%, 2.73%) 〕. By multivariate Cox regression analysis, age, prior thrombotic event and left ventricular ejection fraction (LVEF) were identified (P