May 14, 2001
View Full PaperAssociation Between Blood Pressure Level and the Risk of Myocardial Infarction, Stroke, and Total Mortality
Structured PICO
Does systolic blood pressure predict incident myocardial infarction, stroke, and total mortality better than diastolic or pulse pressure in adults 65 years and older?
P
Population
5,888 adults aged 65 years and older from 4 US centers (Cardiovascular Health Study), including 1,961 men and 2,941 women at risk for incident myocardial infarction or stroke.
I
Intervention
Systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure levels (observational exposure)
O
Outcome
Incident myocardial infarction, stroke, and total mortalityhard clinical
In older adults, systolic blood pressure is a stronger single predictor of incident cardiovascular events and total mortality than diastolic blood pressure or pulse pressure.
Abstract
BACKGROUND: Recent reports have drawn attention to the importance of pulse pressure as a predictor of cardiovascular events. Pulse pressure is used neither by clinicians nor by guidelines to define treatable levels of blood pressure. METHODS: In the Cardiovascular Health Study, 5888 adults 65 years and older were recruited from 4 US centers. At baseline in 1989-1990, participants underwent 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 adjustment for potential confounders, systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure were directly associated with the risk of incident myocardial infarction and stroke. Only SBP was associated with total mortality. Importantly, SBP was a better predictor of cardiovascular events than DBP or pulse pressure. In the adjusted model for myocardial infarction, a 1-SD change in SBP, DBP, and pulse pressure was associated 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 or 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 SBP, 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 with treated hypertension, the hazard ratios for the association of SBP with the risks for myocardial infarction and stroke were less pronounced than in those without treated hypertension. CONCLUSION: In this population-based study of older adults, although all measures of blood pressure were strongly and directly related to the risk of coronary and cerebrovascular events, SBP was the best single predictor of cardiovascular events.