Association between blood pressure and risk of ischemic stroke among individuals with dementia: A nationwide cohort study

Prior research has established a positive correlation between blood pressure (BP) and ischemic stroke in the general population; however, this association has not been investigated in dementia patients. A population-based cohort of 73,130 individuals with newly diagnosed dementia who underwent a Korean national health checkup after diagnosis was followed up until the end of 2019. Individuals were classified according to their systolic (SBP) and diastolic BP (DBP) during health checkups. Multivariable Cox proportional hazards regression was performed, calculating the hazard ratios (HRs) and 95% confidence intervals (CIs) for incident ischemic stroke. During a mean follow-up of 3.6 years, 4446 (6.1%) patients developed ischemic stroke. In all-cause dementia patients, the risk of ischemic stroke increased after SBP/DBP exceeded 130/90 mmHg compared with SBP 120–129 mmHg and DBP 70–79 mmHg (reference) (both P for trend <0.001). Similar trends were observed in patients with Alzheimer’s disease and vascular dementia. In particular, SBP/DBP ≥ 140/90 mmHg and SBP 100–109 mmHg were associated with incrementally higher risks of ischemic stroke and a decreased risk of Alzheimer’s disease, respectively (both P for trend <0.001). The positive linear association of SBP and DBP with ischemic stroke in all-cause dementia remained after stratification by sex and antihypertensive medication use, and the association between SBP and ischemic stroke was greater among younger individuals (40–79 years old). In conclusion, both SBP and DBP showed positive linear relationships with the risk of incident ischemic stroke in dementia patients. Achievement of the target BP may be important for stroke prevention in individuals with dementia.