Background: Stroke is a major cause of disability in the elderly and considerably increases the risk of dementia, which is another important source of disability. This population-based study aimed to examine the risk of dementia in patients with stroke compared with non-stroke cases with similar comorbidities.
Methods: Using the Taiwan National Health Insurance databank covering the period 2001-2007, this retrospective cohort study evaluated the risk of dementia in 10,884 patients with first stroke who had no history of dementia. In this study, we performed a 1:5 case-control matched analysis, in which cases were matched to controls based on their estimated propensity scores, which were estimated with demographics and associated risk factors. This approach reduced selection bias. Cox proportional hazards regression analysis was then used to estimate the risk of dementia in stroke patients.
Results: During the 5-year follow-up period, 1,487 (13.74%) stroke and 1,402 (2.59%) non-stroke patients suffered dementia. Stroke was independently associated with a 6.09 (95% confidence interval [CI], 5.66 to 6.55) times greater risk of dementia 5 years after stroke. Older age was associated with a higher incidence of dementia after stroke. Each stroke type had different impacts on the occurrence of dementia. The hazard ratio of dementia among hemorrhagic stroke patients was much higher than those of ischemic stroke and controls.
Conclusion: The findings of this study suggest that stroke confers an increased risk of dementia, especially in the elderly and in patients with hemorrhagic stroke. We advocate the need for close observation and enhanced health education programs to benefit patients with stroke.