Blood pressure, blood pressure variability and the risk of poststroke dementia.

Objective: High blood pressure and blood pressure variability are potential, modifiable risk factors of poststroke dementia. We aimed to investigate the association between achieved blood pressure, blood pressure variability and poststroke dementia.
Methods: We studied 17 064 patients with noncardioembolic ischemic stroke included in the Prevention Regimen for Effectively avoiding Second Strokes (PRoFESS) trial. We analysed the data as a single observational cohort. We studied mean achieved SBP and DBP and blood pressure variability defined as coefficient of variation (SD/mean∗100). The association between blood pressure and dementia was investigated with logistic regression analysis, correcting for sociodemographic factors and cardiovascular risk factors.
Results: During 39 818 person-years of follow-up, 817 patients were diagnosed with dementia (2.1 per 100 person-years). We found a significant nonlinear association between mean SBP and the risk of dementia, implying a U-shaped association between mean SBP and dementia. Mean SBP of 120-129 mmHg was associated with a significantly higher risk of dementia than 130-139 mmHg [odds ratio (OR) 1.28; 95% confidence interval (95% CI) 1.03-1.58]. There was no indication of a U-shaped association between mean DBP and dementia, and no significant association between mean DBP categories and dementia. Higher blood pressure variability was associated with an increased risk of dementia (OR 1.06 per point increase, 95% CI 1.02-1.04), independent of mean SBP.
Conclusion: Among patients with a recent noncardioembolic ischemic stroke, there appears to be a U-shaped association between achieved SBP and dementia. High blood pressure variability is associated with an increased risk of poststroke dementia.
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