Factors of post‐stroke dementia: A nationwide cohort study in Taiwan

Aim We investigated the long‐term risk of dementia for up to 10 years in patients with stroke and broadened the correlates. Methods We carried out a case–control study using the Taiwan National Health Insurance Research database in 2000 with a sampled population of 1 million. The study cohort comprised 8236 patients with stroke and no dementia history. We carried out a 1:1 case–control matched analysis on estimated propensity scores. Cox proportional hazards regressions were carried out to estimate the risk of dementia during the 5‐ and 10‐year follow‐up periods. The risk factors were also investigated. Results The stroke cohort was significantly at more risk of dementia during the 5‐ and 10‐year follow‐up periods, with adjusted hazard ratios 1.87 and 1.53, respectively. The patients with ischemic stroke, transient ischemic attack and intracerebral hemorrhage had a significantly higher risk of dementia after 5 and 10 years, with adjusted hazard ratios of 1.81 and 1.49, 1.92 and 1.61, and 2.14 and 1.61, respectively. The significant risk factors of dementia were age ≥60 years, resident in southern and eastern regions, having low insurance range, and antiplatelet use. Conclusions Stroke and the subtypes, including ischemic stroke, transient ischemic attack and intracerebral hemorrhage, increase the long‐term risk of dementia. The incidence of post‐stroke dementia increases yearly, but the relative risk decreases gradually. Older adults, residents in southern and eastern regions, having low insurance range and antiplatelet use were prominent risk factors of post‐stroke dementia in Taiwan. Careful management of stroke and risk factors of post‐stroke dementia with long‐term follow up of cognition should be reinforced. Geriatr Gerontol Int 2019; 19: 815–822.