Dementia after stroke increases the risk of long-term stroke recurrence.

BACKGROUND: Although risk factors for first stroke have been identified, the predictors of long-term stroke recurrence are less well understood. We performed the present study to determine whether dementia diagnosed three months after stroke onset is an independent risk factor for long-term stroke recurrence.
METHODS: We examined 242 patients (age = 72.0 +/- 8.7 years) hospitalized with acute ischemic stroke who had survived the first three months without recurrence and followed them to identify predictors of long-term stroke recurrence. We diagnosed dementia three months after stroke using modified DSM-III-R criteria based on neuropsychological and functional assessments. The effects of conventional stroke risk factors and dementia status on survival free of recurrence were estimated using Kaplan-Meier analyses, and the relative risks (RR) of recurrence were calculated using Cox proportional hazards models.
RESULTS: Dementia (RR = 2.71, 95% CI = 1.36 to 5.42); cardiac disease (RR = 2.18, CI = 1.15 to 4.12); and sex, with women at higher risk (RR = 2.03, CI = 1.01 to 4.10), were significant independent predictors of recurrence, while education (RR = 1.90, CI = 0.77 to 4.68), admission systolic blood pressure >160 mm Hg (RR = 1.80, CI = 0.94 to 3.44) and alcohol intake exceeding 160 grams per week (RR = 1.86, CI = 0.79 to 4.38) were weakly related.
CONCLUSIONS: Our results suggest that dementia significantly increases the risk of long-term stroke recurrence, with additional independent contributions by cardiac disease and sex. Cognitive impairment may be a surrogate marker for multiple vascular risk factors and larger infarct volume that may serve to increase the risk of recurrence. Alternatively, less aggressive medical management of stroke patients with cognitive impairment or noncompliance of such patients with medical therapy may be bases for an increased rate of stroke recurrence.