Incident Heart Disease and Subsequent Stroke Risk in Chinese Adults: A Prospective Analysis of the CHARLS Cohort

<title>Abstract</title> <p> <bold>Background</bold> : China accounts for one-third of the global stroke burden, with stroke incidence more than twice that of Western countries. Heart disease (HD) is a well-established precursor of stroke, but most evidence comes from Western cohorts using static baseline exposure classifications that combine incident and prevalent disease. Whether incident HD, modeled as a time-varying exposure, independently predicts stroke in a nationally representative Chinese cohort remains unclear, as do the modifying role of kidney function and the mediating effect of insulin resistance, indexed by the triglyceride-glucose (TyG) index. <bold>Methods</bold> : Data were obtained from the China Health and Retirement Longitudinal Study cohort (2011–2020). Among 17,708 participants at Wave 1, those aged &lt;45 years, with missing age, baseline HD or stroke, or concurrent HD and stroke in the same survey wave were excluded, leaving 14,492 participants. Time-varying Cox models with cluster-robust standard errors estimated hazard ratios (HRs) for stroke associated with incident HD, with sequential adjustment for demographics, lifestyle factors, comorbidities, systolic blood pressure, and TyG index. Subgroup analyses by estimated glomerular filtration rate (eGFR) and four prespecified sensitivity analyses—landmark analysis, exclusion of early stroke events, reverse causation assessment, and inclusion of same-wave events—were conducted. <bold>Results</bold> : During a maximum 9-year follow-up, 2,363 participants developed incident HD and 943 experienced stroke. In the fully adjusted model, incident HD nearly doubled stroke risk (HR 1.96, 95% confidence interval (CI) 1.55–2.48). This association remained consistent across eGFR strata and sensitivity analyses (HR 2.02, 95% CI 1.64–2.48). Traditional cardiovascular risk factors and insulin resistance explained only approximately 37% of the excess stroke risk. <bold>Conclusions</bold> : Incident HD independently doubled stroke risk in Chinese community-dwelling adults. The limited attenuation after comprehensive adjustment suggests that cardiac thromboembolic pathways are the primary drivers. Clinicians should implement systematic atrial fibrillation screening and intensified stroke prevention immediately after HD diagnosis to help reduce China’s stroke burden. </p>