Orthostatic hypotension as a risk factor for stroke: the atherosclerosis risk in communities (ARIC) study, 1987-1996.

BACKGROUND AND PURPOSE: The association between orthostatic hypotension (OH) and stroke has rarely been investigated in longitudinal studies. The purpose of the present study was to determine whether OH predicts ischemic stroke in a middle-aged, biethnic population after adjustment for known stroke risk factors. Diastolic, systolic, and consensus OH were evaluated for baseline associations and for the ability to predict stroke. METHODS: In 11 707 persons from the Atherosclerosis Risk in Communities (ARIC) cohort who were free of stroke and overt heart disease at baseline, Cox proportional hazards analyses modeled the association between OH at baseline and incident ischemic stroke over 7.9 years of follow-up. OH was defined as a systolic blood pressure drop >/=20 mm Hg (systolic OH), a diastolic blood pressure drop >/=10 mm Hg (diastolic OH), or a drop in either (consensus OH) when a person changed from a supine to standing position. RESULTS: OH was predictive of ischemic stroke, even after adjustment for numerous stroke risk factors (consensus OH: hazard ratio, 2.0; 95% CI, 1.2 to 3.2). While the baseline characteristics associated with OH varied depending on the type of OH, all types of OH had a similar risk of stroke. CONCLUSIONS: OH is an easily obtained measurement that may help to identify middle-aged persons at risk for stroke.