Blood pressure measures and risk of total, ischemic, and hemorrhagic stroke in men

To evaluate which blood pressure measure is the best predictor of risk of total, ischemic, and hemorrhagic stroke. The authors used a prospective cohort study among 11,466 men followed for incident stroke during a median of 19.4 years in the Physicians' Health Study. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were self-reported. They calculated relative risks (RRs) and 95% CIs for total, ischemic, and hemorrhagic stroke using Cox proportional hazards models. Model fit was compared using the chi(2) test statistic from likelihood ratio tests. During follow-up, 508 strokes occurred (411 ischemic, 89 hemorrhagic, and eight of unknown etiology). For each 10-mm Hg increase in SBP, the multivariable RRs were 1.31 (95% CI: 1.20 to 1.42) for total stroke, 1.28 (95% CI: 1.16 to 1.40) for ischemic stroke, and 1.38 (95% CI: 1.13 to 1.68) for hemorrhagic stroke. Although DBP, pulse pressure, and mean arterial pressure were all significant predictors of stroke risk, none was a significantly better predictor than SBP alone. Adding DBP did not significantly improve the model fit of SBP alone for any stroke type. In this large cohort of initially healthy men, systolic blood pressure was a consistent and significant predictor of total, ischemic, and hemorrhagic stroke. Systolic blood pressure alone was the only measure necessary to predict risk of total stroke or its major subtypes.