[Analysis on prediction and mediating effects of triglyceride-glucose body mass index on stroke incidence based on cohort study].

内容摘要

Objective: To investigate the prediction and mediating effects of triglyceride-glucose body mass index (TyG-BMI) on the incidence of stroke. Methods: A total of 18 062 residents free of stroke at baseline surveys of chronic disease cohort study in Pudong New District of Shanghai during 2013-2020 were followed until December 2024. Data were collected through questionnaires, physical examinations, and laboratory tests. Missing data were handled using multiple imputation. A Cox proportional hazards regression model was constructed to predict stroke risk and model performance was evaluated by using the concordance index (C-index), time-dependent receiver operating characteristic (ROC) curves, and the Brier score. Subsequently, the prediction and mediating effects of TyG-BMI were analyzed. Results: In the prediction model, the TyG-BMI index showed a HR of 1.00 (95%CI: 1.00-1.01), with a P=0.017. The model demonstrated a C-index of 0.71. Time-dependent area under ROC values were 0.770 (5-year), 0.717 (8-year), and 0.716 (10-year), while Brier scores were 0.005 3 (5-year), 0.043 7 (8-year), and 0.065 2 (10-year). Mediation analysis revealed hypertension mediated 51.9% of total effect of TyG-BMI on stroke (indirect effect: 0.028; total effect: 0.054), diabetes mediated 28.6% of total effect of TyG-BMI on stroke (indirect effect: 0.012; total effect: 0.042). Conclusions: The prediction model demonstrated reasonable accuracy and robustness, indicating that it could serve as a practical tool for screening the populations at high risk. TyG-BMI has both direct and indirect effects, mediated through hypertension or diabetes, on stroke incidence. 目的： 基于浦东新区慢性病危险因素研究队列，探讨甘油三酯葡萄糖体重指数（TyG-BMI）对脑卒中发病的预测效能及中介效应。 方法： 纳入2013-2020年上海市浦东新区18 062名基线无脑卒中居民，随访至2024年12月。通过问卷调查、体格检查和实验室检测收集数据，采用多重填补处理缺失值。使用Cox比例风险回归构建预测模型，通过C指数、时间依赖性受试者工作特征曲线、Brier分数评估模型性能，分析TyG-BMI的预测效能及中介效应。 结果： 预测模型中TyG-BMI的HR值（95%CI）为1.00（1.00~1.01）（P=0.017）。模型的一致性指数为0.71，5、8、10年受试者工作特征曲线下面积分别为0.770、0.717、0.716，Brier分数分别为0.005 3、0.043 7、0.065 2。中介分析结果显示，高血压介导的间接效应（0.028）占TyG-BMI对脑卒中发病总效应（0.054）的51.9%，糖尿病介导的间接效应（0.012）占TyG-BMI对脑卒中发病总效应（0.042）的28.6%。 结论： 本研究构建的脑卒中预测模型具有一定的准确性和稳健性，可为脑卒中高危人群筛查提供实用工具，TyG-BMI对脑卒中的发病存在直接和间接（通过高血压/糖尿病）的影响。.