Abstract
BACKGROUND: To compare stroke severity, as well as usage and outcomes of mechanical thrombectomy (MT) for acute ischemic stroke (AIS) in patients with and without dementia. METHODS: Study of the US hospitalizations with AIS and documented National Institutes of Health Stroke Scale scores from October 1, 2016, to December 31, 2017. AIS hospitalizations with documented dementia were compared with AIS hospitalizations without dementia for stroke severity at onset, use of MT, and outcomes at discharge. Outcomes included favorable discharge disposition (home without assistance), in-hospital mortality, and radiographic intracranial hemorrhage. RESULTS: Among 179 665 AIS admissions with recorded National Institutes of Health Stroke Scale score during the 15-month study period, 18 255 (10.2%) had preexisting dementia (62.5% women). The median age at stroke was 84 (interquartile range, 78-89) versus 69 (interquartile range, 59-79) years; and median presenting National Institutes of Health Stroke Scale score was 7 (interquartile range, 3-15) versus 4 (interquartile range, 2-10) in hospitalizations with versus without dementia. There was a stepwise association between increasing severity of the index stroke and the prevalence of dementia. In multivariable analysis, dementia was associated with significantly lower (odds ratio [OR], 0.43 [95% CI, 0.35-0.53]; P<0.001) odds of receiving MT, but not with the use of intravenous thrombolysis (OR, 0.95 [95% CI, 0.86-1.06]; P=0.4). In-hospital mortality occurred in 21.3% versus 11.2% following MT in hospitalizations with versus without dementia (P<0.001). However, after adjustment for stroke severity, no associations were found between dementia and in-hospital mortality (OR, 1.48 [95% CI, 0.90-2.43]; P=0.15) or favorable discharge outcome (OR, 0.61 [95% CI, 0.33-1.32]; P=0.12) following MT. Dementia was associated with increased likelihood of intracranial hemorrhage after MT (OR, 1.57 [95% CI, 1.03-2.40]; P=0.04). CONCLUSION: One in 10 among all, and 1 in 4 among those aged ≥80 years had preexisting dementia at stroke onset. While patients with dementia were more likely to present with more severe deficits, MT was less frequently used in this population. Dementia was not independently associated with in-hospital mortality beyond stroke severity at onset, but increased the risk of intracranial hemorrhage following MT.