Adverse Influence of Pre-Stroke Dementia on Short-Term Functional Outcomes in Patients with Acute Ischemic Stroke: The Fukuoka Stroke Registry.

BACKGROUND Dementia and stroke are major causes of disability in the elderly. However, the association between pre-stroke dementia and functional outcome after stoke remains unresolved. We aimed to determine this association in patients with acute ischemic stroke. METHODS Among patients registered in the Fukuoka Stroke Registry from June 2007 to May 2015, 4,237 patients with ischemic stroke within 24 h of onset, who were functionally independent before the onset, were enrolled in this study. Pre-stroke dementia was defined as any type of dementia that was present prior to the index stroke. Primary and secondary study outcomes were poor functional outcome (modified Rankin Scale 3-6) at 3 months after the stroke onset and neurological deterioration (≥2-point increases on the National Institutes of Health Stroke Scale score during hospitalization), respectively. For propensity score (PS)-matched cohort study to control confounding variables for pre-stroke dementia, 318 pairs of patients with and without pre-stroke dementia were also selected on the basis of 1:1 matching. Multivariable logistic regression models and conditional logistic regression analysis were used to quantify associations between pre-stroke dementia and study outcomes. RESULTS Of all 4,237 participants, 347 (8.2%) had pre-stroke dementia. The frequencies of neurological deterioration and poor functional outcome were significantly higher in patients with pre-stroke dementia than in those without pre-stroke dementia (neurological deterioration, 16.1 vs. 7.1%, p < 0.01; poor functional outcome, 63.7 vs. 27.1%, p < 0.01). Multivariable analysis showed that pre-stroke dementia was significantly associated with neurological deterioration (OR 1.67; 95% CI 1.14-2.41; p < 0.01) and poor functional outcome (OR 2.91; 95% CI 2.17-3.91; p < 0.01). In the PS-matched cohort study, the same trends were observed between the pre-stroke dementia and neurological deterioration (OR 2.60; 95% CI 1.17-5.78; p < 0.01) and between the dementia and poor functional outcome (OR 3.62; 95% CI 1.89-6.95; p < 0.01). CONCLUSIONS Pre-stroke dementia was significantly associated with higher risks for poor functional outcome at 3 months after stroke onset as well as for neurological deterioration during hospitalization in patients with acute ischemic stroke.