High Blood Pressure, Physical and Cognitive Function, and Risk of Stroke in the Oldest Old

Abstract

Epidemiological studies have shown mixed findings on the association between hypertension and stroke in the oldest old. Heterogeneity of the populations under study may underlie variation in outcomes. We examined whether the level of physical and cognitive function moderates the association between blood pressure and stroke. We included 513 subjects aged 85 years old from the population-based Leiden 85-plus Study. Systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure were measured at baseline. Activities of daily living and Mini-Mental State Examination were assessed to estimate level of physical and cognitive function, respectively. Five-year risk of stroke was estimated with Cox regression analysis. In the entire cohort, there were no associations between various measures of blood pressure and risk of stroke except for the inverse relation between pulse pressure and stroke risk (hazard ratio [HR], 0.80 [95% confidence interval [CI], 0.66-0.98]). Among subjects with impaired physical functioning, higher systolic blood pressure (HR, 0.74 [95% CI, 0.59-0.92]), mean arterial pressure (HR: 0.68 [95% CI, 0.47-0.97]), and pulse pressure (HR, 0.71 [95% CI, 0.55-0.93]) were associated with reduced risk of stroke. Likewise, among subjects with impaired cognitive functioning, higher systolic blood pressure was associated with reduced risk of stroke (HR, 0.80 [95% CI, 0.65-0.98]). In subjects with unimpaired cognitive functioning, higher diastolic blood pressure (HR: 1.98 [95% CI, 1.21-3.22]) and mean arterial pressure (HR, 1.70 [95% CI, 1.08-2.68]) were associated with higher risk of stroke. Our findings suggest that impaired physical and cognitive function moderates the association between blood pressure and stroke.