Background: The aim of this study was to investigate the influence of poststroke dementia on longterm survival after acute stroke, focusing also on the possible influence of prestroke cognitive decline and previous stroke.
Methods: A total of 451 consecutive acute ischaemic stroke patients admitted to hospital were included in the study and followed up to 12 years. Dementia was diagnosed three months after stroke in 115 patients (25.5%).
Findings: In Kaplan-Meier analysis, poststroke dementia predicted poor longterm survival (5.1 vs 8.8 years, p<0.001). Prestroke cognitive decline had a negative influence on survival of patients with poststroke dementia (3.8 vs 5.8 years, p<0.001). Previous stroke did not have an influence on survival of these patients (p=0.676). In stepwise Cox regression proportional hazards analysis adjusted with significant covariates, poststroke dementia (HR 1.53, p=0.003), advanced age (HR 1.07, p<0.001), severity of stroke (poor Rankin score, HR 1.91, p<0.001), smoking (HR 1.35, p=0.035), cardiac failure (HR 1.61, p=0.003) and atrial fibrillation (HR 1.89, p=0.035) remained as independent predictors of poor longterm survival. Poststroke dementia (HR 2.33, p<0.001), advanced age (HR 1.07, p<0.001) and poor Rankin score (HR 2.15, p=0.001) were associated with death from brain associated causes including infarction, haemorrhage and dementia.
Interpretation: Our large well defined poststroke cohort with longterm follow up indicates that in patients with acute stroke, dementia is a significant predictor of poor longterm survival and death from brain associated causes. Prestroke cognitive decline seems to have an additional negative influence on survival, but previous stroke does not seem to influence survival.