Divergent Causes of Death After Ischemic and Hemorrhagic Stroke in the Reperfusion Era: A Contemporary Cohort Study

Background: Contemporary data on long-term, cause-specific mortality among stroke survivors are sparse, and much of the existing evidence derives from studies performed before the modern reperfusion era. We sought to characterize long-term cause-specific mortality among stroke survivors to discharge (differentiated by stroke subtype) when compared to in-hospital stroke decedents treated under contemporary standards of care. Methods: Using a hybrid billing-code/imaging and large language model-assisted chart-review pipeline, we identified adults hospitalized for ischemic or hemorrhagic stroke in the Observational Study of Cardiac Arrest Risk (OSCAR) cohort (Cedars-Sinai Health System, Los Angeles) between 2017 and 2020, followed through June 30, 2025. Cause of death was determined and classified into 10 categories. Results: Among 1,344 stroke patients (mean age 74.0 ± 14.9 years; ischemic n=1,036 [77.1%], hemorrhagic n=308 [22.9%]), 203 (15.1%) did not survive the index stroke. Of the 1,141 discharged survivors, 625 (54.8%) died over a median follow-up of 5.2 years. Cerebrovascular causes predominated during index stroke hospitalization (36.0%) but accounted for only 15.5% of post-stroke discharge deaths. Among ischemic stroke survivors, cardiac disease was the leading cause of death (31.6%), with sudden cardiac arrest alone accounting for 10.9% of deaths. Among hemorrhagic stroke survivors, cancer (38.9%) was the leading cause of death. Despite these divergent cause-of-death profiles, overall survival did not differ significantly by subtype (median 5.5 vs 5.8 years; P=0.90). Conclusions: In this contemporary, reperfusion-era cohort, causes of death shifted from cerebrovascular predominance in the acute phase to heart disease/cardiac arrest after ischemic stroke, and malignancy after hemorrhagic stroke. These findings argue for development of subtype-specific post-stroke surveillance, including structured longitudinal cardiac and sudden-death risk assessment for ischemic stroke survivors.