Association between blood pressure level and the risk of myocardial infarction, stroke, and total mortality - The cardiovascular health study

Background: Recent reports have drawn attention to the importance of pulse pressure as a predictor of cardiovascular events. Pulse pressure is used ne ither by clinicians nor by guidelines to define treatable levels of blood p ressure. Methods: In the Cardiovascular Health Study, 5888 adults 65 years and older were recruited from 4 US centers. At baseline in 1989-1990, participants u nderwent an extensive examination, and all subsequent cardiovascular events were ascertained and classified. Results: At baseline, 1961 men and 2941 women were at risk for an incident myocardial infarction or stroke. During follow-up that averaged 6.7 years, 572 subjects had a coronary event, 385 had a stroke, and 896 died. After ad justment for potential confounders, systolic blood pressure (SBP), diastoli c blood pressure (DBP), and pulse pressure were directly associated with th e risk of incident myocardial infarction and stroke. Only SEP was associate d with total mortality. Importantly, SEP was a better predictor of cardiova scular events than DBP or pulse pressure. In the adjusted model for myocard ial infarction, a 1-SD change in SEP, DBP, and pulse pressure was associate d with hazard ratios (95% confidence intervals) of 1.24 (1.15-1.35), 1.13 ( 1.04-1.22), and 1.21 (1.12-1.31), respectively; and adding pulse pressure o r DBP to the model did not improve the fit. For stroke, the hazard ratios ( 95% confidence intervals) were 1.34 (1.21-1.47) with SEP, 1.29 (1.17-1.42) with DBP, and 1.21 (1.10-1.34) with pulse pressure. The association between blood pressure level and cardiovascular disease risk was generally linear; specifically, there was no evidence of a J-shaped relationship. In those w ith treated hypertension, the hazard ratios for the association of SEP with the risks for myocardial infarction and stroke were less pronounced than i n those without treated hypertension. Conclusion: In this population-based study of older adults, although all me asures of blood pressure were strongly and. directly related to the risk of coronary and cerebrovascular events, SEP was the best single predictor of cardiovascular events.