Background: Stroke and dementia are closely related but no prospective study ever focused on dementia in patients with intracerebral hemorrhage (ICH).
Objective: To determine incidence, prognostic factors and possible mechanisms of post-ICH dementia in a large population of non-demented ICH patients over a long period of follow-up.
Methods: Prospective cohort of consecutive adults with spontaneous ICH. Patients free of dementia and alive at 6 months were included. We studied clinical and neuroradiological (MRI) biomarkers with a prespecified subgroup analysis according to ICH location. Age-adjusted analyses were used to select variables (p<0.1) included in multivariable models that took into account death as competing risk.
Results: In a cohort of 218 ICH patients (108 males; median age 67.5, interquartile range (IQR) 55-76), 63 patients developed new onset dementia during a median follow-up of 5.4 years (IQR, 4.2-5.8). At 1 year after ICH, the overall incidence of dementia was 20% (95% CI 15-25). It differed between lobar ICH (n=77, 30% 95% CI 20-40) and non lobar ICH (n=141, 16% 95% CI 10-22). Prognostic factors of new onset dementia were lobar Iocation (Hazard Ratio (HR): 2.21; 95% CI 1.30-3.79), older age (HR: 1.06 per year; 95% CI 1.03-1.09), history of previous stroke or transient ischemic attack (HR: 2.56; 95% CI 1.42-4.61), higher NIHSS (HR: 1.03 per year; 95% CI 1.01-1.06), severe leucoaraïosis (HR: 2.87; 95% CI 1.63-5.07) and recurrent stroke during follow-up (HR: 3.22; 95% CI 1.27-8.15). Prognostic neuroradiological biomarkers were increasing cortical atrophy (HR: 2.7; 95% CI 1.7-4.3), presence of disseminated superficial siderosis (HR: 7.10; 95% CI 3.93-12.83), higher number of lobar cerebral microbleeds (HR: 3.40; 95%CI 1.87-6.18). Among lobar ICH, superficial siderosis was a strong predictor (HR: 6.74; 95% CI 3.32-13.68).
Conclusion: The incidence of new onset dementia is high after ICH with a strong influence of lobar location. Among patients with lobar ICH, prognostic factors suggested a strong implication of underlying cerebral amyloid angiopathy that might predict future risk of dementia. Results of our study suggest that all prognostic factors of dementia are already present before the ICH occurs.