Supplementary file 1_Co-recorded conditions in ischemic and hemorrhagic stroke: a 20-year national analysis of 598,186 natural deaths with machine learning.docx

For hemorrhagic stroke, 12 association rules were identified; the strongest involved co-occurrence of infectious and respiratory diseases (e.g., {hypertension = Yes, infectious_disease = Yes} → {respiratory_disease = Yes}, lift = 2.57) and of endocrine/metabolic conditions with hypertension (lift = 1.67), whereas the rule {mental_disorders = Yes} → {hypertension = Yes} (lift = 1.27, confidence = 53.9%) was the weakest of the 12 rules.

In contrast, ischemic stroke yielded 8 rules reflecting associations among infectious, respiratory, genitourinary, and endocrine/metabolic conditions. The logistic regression model achieved an AUC of 0.768 for predicting stroke subtype, with consistent performance across sensitivity analyses. Age-standardized analyses showed that ischemic stroke proportion increased from 48.8 to 51.5% over 20 years, with approximately half of the crude increase attributable to population aging (crude ischemic proportion reached 54.7%).

Co-recorded condition burden increased substantially in both subtypes (≥3 co-recorded conditions in ischemic stroke: 24.8–33.3%). We observed that hemorrhagic and ischemic stroke have different co-occurrence patterns of co-recorded conditions: hemorrhagic stroke exhibited simpler co-occurrence patterns centered on hypertension together with infectious, respiratory, and endocrine/metabolic conditions, while ischemic stroke was characterized by clustered cardiovascular and metabolic multimorbidity.

These findings warrant further investigation in prospective studies.</p>