Isolated Systolic Hypertension and the Long-Term Risk of Stroke: A 20-Year follow-up of the National Health and Nutrition Survey.
Background and Purpose: Isolated systolic hypertension (ISH) is frequently observed in elderly persons. The effect of ISH on the long-term risk for stroke and stroke subtypes is unclear. We performed this study to evaluate the long-term risk of stroke in persons with ISH. METHODS: We evaluated the incidence of stroke and stroke subtypes(ischemic and hemorrhagic) in a nationally representative cohort of 14,047 adults who participated in the First National Health and Nutrition Examination Survey during the 20-year follow-up. ISH was defined as a systolic blood pressure(BP)>160mmHg and diastolic BP<90mmHg. RESULTS: A total of 376 persons with ISH, 8985 persons with normotension, and 4686 persons with classic hypertension were followed. During the follow-up period, the annual incidences of ischemic stroke and intracerebral hemorrhage for patients with ISH were 1.7% and .05% respectively. After adjusting for differences in age, race,and gender, the risk for ischemic stroke was increased in persons with ISH compared to persons with normotension (odds ratio [OR]=1.6, 95% confidence interval [CI]=1.1 to 2.2). The increased risk was similar to persons with classic hypertension (OR=1.3, 95% CI=1.03 to 1.6). The risk of intracerebral hemorrhage was increased in persons with classic hypertension (OR=3.0, 95% CI=1.5 to 7.1) but not in persons with ISH (OR=0.7, 95% CI=0.1 to 2.3). CONCLUSION: Persons with ISH are at increased risk for ischemic stroke, similar to those with classic hypertension.