In older people, observational data are unclear concerning the relationships of systolic and diastolic blood pressure with cardiovascular and total mortality. We examined which combinations of systolic, diastolic, pulse, and mean arterial pressure best predict total and cardiovascular mortality in older adults.
In 1981, the National Institute on Aging initiated its population-based Established Populations for Epidemiologic Studies of the Elderly in 3 communities. At baseline, 9431 participants, aged 65 to 102 years, had blood pressure measurements, along with measures of medical history, use of medications, disability, and physical function. During an average follow-up of 10.6 years among survivors, 4528 participants died, 2304 of cardiovascular causes.
In age- and sex-adjusted survival analyses, the lowest overall death rate occurred among those with systolic pressure less than 130 mm Hg and diastolic pressure 80 to 89 mm Hg; relative to this group, the highest death rate occurred in those with systolic pressure of 160 mm Hg or more and diastolic pressure less than 70 mm Hg (relative risk, 1.90; 95% confidence interval, 1.47-2.46). Both low diastolic pressure and elevated systolic pressure independently predicted increases in cardiovascular (P<.001) and total (P<.001) mortality. Pulse pressure correlated strongly with systolic pressure (R = 0.82) but was a slightly stronger predictor of both cardiovascular and total mortality. In a model containing pulse pressure and other potentially confounding variables, diastolic pressure (P = .88) and mean arterial pressure (P = .11) had no significant association with mortality.
Pulse pressure appears to be the best single measure of blood pressure in predicting mortality in older people and helps explain apparently discrepant results for low diastolic blood pressure.