Intravenous thrombolysis for acute ischemic stroke is associated with lower risk of post-stroke dementia: A nationwide cohort study

Introduction: Dementia after stroke is common and is a great concern for patients and their caregivers. The objective was to investigate if intravenous thrombolysis (IVT) for acute ischemic stroke (AIS) was associated with lower risk of dementia after stroke. Patients and methods: When IVT was introduced in Denmark, not all eligible patients were treated due to restricted access. We conducted a nationwide register-based cohort study of all patients with AIS in Denmark from 2004 to 2011. IVT-treated patients were propensity score-matched with comparable non-treated patients. Cox proportional hazards regression was used to estimate the hazard ratio (HR) for all-cause and vascular dementia 2, 5, and 10 years after stroke. Results: Of the 5919 patients eligible for the study, 2305 IVT-treated patients were propensity score-matched with 2305 non-treated patients. Mean (SD) age was 66.6 (13.3) and 61.2% were male. Rate of all-cause dementia was lower for the IVT-treated 2 years (8.4/1000 person years (PY) vs 13.6/1000 PY, HR 0.63 (0.40-0.99)) and 5 years after stroke (7.3/1000 PY vs 11.4/1000 PY, HR 0.65 (0.46-0.91)). 10 years after stroke, the rates of all-cause dementia remained in favor of IVT (8.0/1000 PY vs 9.8/1000 PY, HR 0.83 (0.64-1.07)). IVT-treated had lower rates of vascular dementia 2 years (2.4/1000 PY vs 7.4/1000 PY, HR 0.33 (0.15-0.71)), 5 years (2.3/1000 PY vs 6.2/1000 PY, HR 0.38 (0.23-0.65)), and 10 years after stroke (3.0/1000 PY vs 5.4/1000 PY, HR 0.56 (0.38-0.81)). Conclusion: IVT treatment was associated with lower long-term risk of both vascular and all-cause dementia after AIS.