Intracerebral hemorrhage risk in Alzheimer's disease patients on anticoagulants: A nationwide cohort study

Background: The risk of intracerebral hemorrhage (ICH) in Alzheimer's disease (AD) patients undergoing anticoagulation (AC) remains unclear. Objective: This nationwide cohort study assessed ICH risk in AC-treated AD patients. Methods: Using Taiwan's National Health Insurance Research Database, we identified 1638 AC-treated AD patients and established four matched cohorts: AD with AC, AD without AC, non-AD with AC, and non-AD without AC. We applied inverse probability of treatment weighting (IPTW) and competing risks regression (CRR) to adjust for confounders and mortality risk. Cox proportional hazards regression estimated ICH risk. Results: The ICH incidence per 100 person-years was 2.21 in AD patients with AC, 1.03 without AC, 1.71 in non-AD with AC, and 0.28 in non-AD without AC. After IPTW adjustment, compared to non-AD without AC, AD patients with AC had the highest ICH risk (aHR 1.94, 95% CI: 1.44–2.61), followed by non-AD with AC (aHR 1.84, 95% CI: 1.51–2.23) and AD without AC (aHR 1.74, 95% CI: 1.42–2.11). ICH risk in AC-treated AD patients was comparable to non-AD with AC. Subgroup analysis showed higher ICH risk in females and those with hyperlipidemia, diabetes, heart failure, chronic kidney disease, or cancer. Conclusions: AD is associated with increased ICH risk, which is further elevated by AC use. These findings highlight the need for individualized risk-benefit evaluation, particularly in high-risk populations.