Is diastolic hypertension an independent risk factor for stroke in the presence of normal systolic blood pressure in the middle-aged and elderly?

In a prospective population-based study from the Copenhagen City Heart Study, the role of diastolic blood pressure as an independent risk factor of stroke, in the presence of normal systolic blood pressure, was assessed in 6,545 subjects aged 50 to 80 years. Follow-up was 12 years. Subjects were divided into various blood pressure categories according to both diastolic and systolic blood pressure. The risk of stroke was assessed using a multivariate Cox proportional hazards model, taking into account various cardiovascular risk factors (age, sex, smoking, diabetes mellitus, body mass index, and levels of serum cholesterol). After adjustment for risk factors, only subjects with elevated systolic blood pressure had a significantly increased risk of future stroke. The risk of stroke according to blood pressure categories further reflected increasing levels of pulse pressure, with the highest risk of stroke in subjects with the greatest pulse pressure. We conclude that systolic blood pressure is a better predictor of stroke than is diastolic blood pressure, and question whether diastolic blood pressure, in the presence of normal systolic blood pressure, is an independent risk factor for stroke in the middle-aged and elderly.