ORIGINAL INVESTIGATION Pulse Pressure and Mortality in Older People Robert J. Glynn, ScD; Claudia U. Chae, MD; Jack M. Guralnik, MD, PhD; James O. Taylor, MD; Charles H. Hennekens, MD, DrPH Background: In older people, observational data are un- sure 80 to 89 mm Hg; relative to this group, the highest clear concerning the relationships of systolic and dias- death rate occurred in those with systolic pressure of tolic blood pressure with cardiovascular and total mor- 160 mm Hg or more and diastolic pressure less than 70 tality. We examined which combinations of systolic, mm Hg (relative risk, 1.90; 95% confidence interval, diastolic, pulse, and mean arterial pressure best predict 1.47-2.46). Both low diastolic pressure and elevated sys- total and cardiovascular mortality in older adults. tolic pressure independently predicted increases in car- diovascular (P,.001) and total (P,.001) mortality. Pulse Methods: In 1981, the National Institute on Aging ini- pressure correlated strongly with systolic pressure tiated its population-based Established Populations for (R=0.82) but was a slightly stronger predictor of both Epidemiologic Studies of the Elderly in 3 communities. cardiovascular and total mortality. In a model contain- At baseline, 9431 participants, aged 65 to 102 years, had ing pulse pressure and other potentially confounding vari- blood pressure measurements, along with measures of ables, diastolic pressure (P=.88) and mean arterial pres- medical history, use of medications, disability, and physi- sure (P=.11) had no significant association with mortality. cal function. During an average follow-up of 10.6 years among survivors, 4528 participants died, 2304 of car- Conclusions: Pulse pressure appears to be the best single diovascular causes. measure of blood pressure in predicting mortality in older people and helps explain apparently discrepant results Results: In age- and sex-adjusted survival analyses, the for low diastolic blood pressure. lowest overall death rate occurred among those with sys- tolic pressure less than 130 mm Hg and diastolic pres- Arch Intern Med. 2000;160:2765-2772 N MIDDLE-AGED populations, both pulse pressure and a diminished associa- From the Division of Preventive systolic and diastolic blood pres- tion between systolic and diastolic pres- 21 Medicine, Department of sure have strong, linear relation- sure. This may lead to differing relation- Medicine, Brigham and ships with cardiovascular and to- ships of systolic and diastolic pressure with Women’s Hospital and Harvard tal mortality.1-5 Because of the mortality in older people. Medical School, Boston, Mass Ihigh correlation between systolic and di- It is also possible that pulse pressure (Drs Glynn and Chae); astolic pressure, studies examining car- is the measure of blood pressure most Department of Biostatistics, diovascular risk in this age group com- strongly related to cardiovascular risk in Harvard School of Public monly find that diastolic pressure provides older people, and that consideration of Health, Boston (Dr Glynn); little additional prognostic information af- pulse pressure may explain the apparent Cardiology Division, 1-4 Department of Medicine, ter consideration of systolic pressure. In increased risk associated with low dias- Massachusetts General older people, however, observational stud- tolic pressure. Several prospective stud- 6-13 Hospital, Boston (Dr Chae); ies have been less consistent and have ies have found that elevated pulse pres- Epidemiology, Demography, commonly found U- or J-shaped relation- sure, which reflects increased arterial and Biometry Program, ships of blood pressure with mortality, es- stiffness with age, is associated with risk National Institute on Aging, pecially for diastolic pressure. In some of myocardial infarction, congestive heart Bethesda, Md (Dr Guralnik); studies, individuals with the lowest blood failure, and cardiovascular and total mor- East Boston Neighborhood pressure had the highest mortality.14,15 tality.22-27 However, pulse pressure is Health Center, East Boston, Treatment implications of these relation- strongly correlated with systolic pres- Mass (Dr Taylor); and 16-20 Department of Medicine, ships remain controversial. With the sure, and it remains unclear whether it pro- Epidemiology, and Public loss of aortic compliance, systolic pres- vides independent prognostic informa- 28 Health, University of Miami sure rises with age in industrialized coun- tion or is useful in clarifying J-curves. School of Medicine, Miami, Fla tries, while diastolic pressure declines af- Using data from 3 population- (Dr Hennekens). ter about age 60 years, leading to increased based cohorts of the Established Popu- (REPRINTED) ARCH INTERN MED/ VOL 160, OCT 9, 2000 WWW.ARCHINTERNMED.COM 2765 ©2000 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/29/2021 SUBJECTS AND METHODS to 1992, giving an average follow-up of 10.6 years (range, 9.1-11.1 years) among survivors. Of the 9431 partici- SUBJECTS AND MEASURES pants, 4528 died, and death certificates were obtained for 4494. A single trained nosologist coded the underlying cause In 1981, the National Institute on Aging initiated its Es- of death according to the International Classification of Dis- tablished Populations for Epidemiologic Studies of the El- eases, Ninth Revision.36 We used these codes to classify deaths derly studies of community-dwelling persons aged 65 years as being caused by cardiovascular disease including stroke and older in 3 locations: East Boston, Mass; Washington (codes 401-459) or other causes. and Iowa counties, Iowa; and New Haven, Conn. During 1982 and 1983, surveys were conducted in the entire popu- STATISTICAL ANALYSIS lations of persons aged 65 years and older in East Boston and Iowa and in a stratified sample of residents of New Ha- We first determined correlations among the measures of ven. To maximize participation, trained interviewers vis- blood pressure to quantify their interrelationships. To ited the homes of all eligible participants. Participation rates examine the joint association of systolic and diastolic ranged from 80% to 85%, with 3809 participants in East pressure with mortality, we classified participants Boston, 3673 participants in Iowa, and 2812 participants according to categories of both variables. Categories in New Haven, for a total population of 10294 community- used were the same as in a previous study of blood pres- dwelling elderly subjects. Because some individuals par- sure in one of these populations,12 except that a priori ticipated through a proxy, 9431 participants had baseline we grouped individuals with systolic pressure between blood pressure measurements, and they constitute the co- 140 and 159 mm Hg and also formed a single group hort for the current study. among those with diastolic pressure between 70 and 79 In East Boston and New Haven, the trained inter- mm Hg. Thus, we partitioned the population into 16 viewer took 3 blood pressure measurements at 30-second groups according to category of systolic pressure (,130, intervals by means of a standard mercury sphygmoma- 130-139, 140-159, or $160 mm Hg) and category of nometer, after the participant had been seated for at least diastolic pressure (,70, 70-79, 80-89, or $90 mm Hg). 5 minutes, according to the protocol used in the Hyper- We used proportional hazards analyses to compare age- tension Detection and Follow-up Program.29 Two mea- and sex-adjusted total and cardiovascular death rates surements were taken in Iowa. For this study, systolic across these 16 categories. pressure was the average of all systolic measures; dias- To examine whether simpler models might summa- tolic pressure was the average of all diastolic measures; rize these relationships, we compared the ability of both pulse pressure was systolic minus diastolic pressure; single measures and pairs of measures of blood pressure and mean arterial pressure was [systolic+(23diastolic to predict total and cardiovascular mortality. We catego- pressure)]/3. rized pulse pressure and mean arterial pressure accord- The interviewer also collected information about ing to approximate quartiles in the population. We com- other characteristics potentially related to both blood pared the ability of alternative models to predict pressure and mortality. Participants reported their height mortality by means of the R2 statistic for survival analy- and weight, present and past use of cigarettes and alcohol, sis and the likelihood ratio–based discrimination index and whether they were ever told by a physician that they D (defined as the model likelihood ratio x2−1 divided by had myocardial infarction, stroke, or cancer. Angina was the −2 log likelihood of the null model) described by identified by the Rose questionnaire.30 All medications Harrell and colleagues.37 We used likelihood ratio tests used in the 2 weeks before the interview were identified to determine whether adding variables to a model sig- by direct inspection. Disability was identified through nificantly improved the fit. Additional models included reports of problems with activities of daily living31 and other variables that may affect both blood pressure and problems with physical function by a 3-item scale.32 We risk of death, but were restricted to the 4054 deaths in classified participants as low in physical activity when 8715 participants with complete data on these potential they reported not exercising vigorously at least once a confounding variables. week,