The Impact of Antiplatelet Use on the Risk of Intracerebral Hemorrhage in Patients with Alzheimer's Disease: A Nationwide Cohort Study

Background: Antiplatelet use on the risk of intracerebral hemorrhage (ICH) in patients with Alzheimer's disease (AD) has not yet been completely elucidated. Objective: This large epidemiologic study aims to estimate the risk of ICH in AD patients treated with antiplatelet therapy (APT). Methods: Using data from Taiwan's National Health Insurance Research Database, ICH risk in APT-treated AD patients with a validated diagnosis (N = 824) was determined. AD without APT and non-AD with and without APT comparison cohorts were selected. To adjust for confounders and competing risk of death, inverse probability of treatment weighting using propensity scores and competing risks regression (CRR) were applied. Cox proportional hazards regression analysis estimated ICH risk in all cohorts comparing with non-AD without APT. Results: Among the 824 AD patients with APT, 79.6% were prescribed aspirin. ICH incidence rates in the AD (with/without APT) and non-AD (with/without APT) cohorts were 2.88/2.70 and 2.24/1.20 per 1,000 person-years, respectively. Overall, AD with (adjusted hazards ratio (aHR), 2.29; 95% CI, 1.19-4.38) and without (aHR, 1.97; 95% CI, 1.08-3.61) APT and non-AD with APT (aHR, 1.80; 95% CI, 1.34-2.42) were at a higher risk and had elevated subdistribution HR obtained from CRR than non-AD without APT controls. However, the risk was comparable between the AD cohorts with and without APT (HR, 1.16; 95% CI, 0.51-2.66). Conclusions: Our study indicated both the APT and non-APT users in AD population yielded higher ICH risks. However, whether APT use potentiate the risk of ICH in AD patients may warrant further evaluation.