Mortality in patients with dementia after ischemic stroke

Abstract

Objective: Although dementia is typically considered to be a consequence of a variety of neurologic diseases, it can also serve as a risk factor for other adverse outcomes. The authors investigated dementia as a predictor of long-term survival among patients with ischemic stroke.

Methods: Neurologic, neuropsychological, and functional assessments were administered to 453 patients (mean age +/- SD, 72.0 +/- 8.3 years) 3 months after ischemic stroke. The authors diagnosed dementia in 119 (26.3%) of the patients using modified Diagnostic and Statistical Manual of Mental Disorders, Revised 3rd Edition, criteria requiring deficits in memory and two or more additional cognitive domains as well as functional impairment. Dementia as a predictor of long-term survival during up to 10 years of follow-up was then investigated.

Results: The mortality rate was 15.90 deaths per 100 person-years among patients with dementia and 5.37 deaths per 100 person-years among nondemented patients. A Cox proportional hazards analysis found that the relative risk (RR) of death was increased in association with dementia (RR = 2.4; 95% CI = 1.6 to 3.4), adjusting for the following: a major hemispheral stroke syndrome (RR = 1.4); a middle cerebral artery territory index stroke (RR = 1.7); a Stroke Severity Scale score of > or = 4, representing more severe stroke (RR = 1.8); atrial fibrillation (RR = 1.8); congestive heart failure (RR = 2.2); recurrent stroke occurring during follow-up (RR = 3.9); and demographic variables. The risk of death increased in association with the severity of dementia, but it did not differ by dementia subtype.

Conclusions: Dementia is a significant independent risk factor for reduced survival after ischemic stroke, adjusting for other recognized predictors of mortality. The authors hypothesize that patients with dementia are at an elevated risk of mortality because of their increased burden of cerebrovascular disease, a tendency toward undertreatment for stroke prophylaxis among clinicians, or patient noncompliance with treatment regimens.