Influence of Pre-Existing Mild Cognitive Impairment and Dementia on Post-Stroke Mortality. The Dijon Stroke Registry

Objective: We assessed the association between pre-stroke cognitive status and 90-day case-fatality. Methods: Patients with ischemic stroke (IS) or spontaneous intracerebral hemorrhage (ICH) were prospectively identified among residents of Dijon, France, between 2013 and 2015, using a population-based registry. Association between pre-stroke cognitive status and case-fatality at 90 days was evaluated using Cox regression. Results: Seven hundred sixty-two patients were identified, and information about pre-stroke cognitive status was obtained for 716 (92.6%) of them, including 603 IS (84.2%) and 113 ICH (15.8%). Before stroke, 99 (13.8%) patients had mild cognitive impairment (MCI) and 98 (13.7%) had dementia. Patients with cognitive impairment were older, had a higher prevalence of several risk factors, more severe stroke, more frequent ICH, and less admission to stroke unit. Case-fatality rate at 90 days was 11.7% in patients without cognitive impairment, 32.3% in MCI patients, and 55.1% in patients with dementia. In multivariable analyses, pre-existing MCI (hazard ratio [HR] 2.22, 95% CI 1.21-4.05, p = 0.009) and dementia (HR 4.35, 95% CI 2.49-7.61, p < 0.001) were both associated with 90-day case-fatality. Conclusion: Pre-stroke MCI and dementia were both associated with increased mortality. These associations were not fully explained by baseline characteristics, pre-stroke dependency, stroke severity or patient management, and underlying reasons need to be investigated.