Clinical Trial Details
— Status: Active, not recruiting
Administrative data
NCT number |
NCT00005133 |
Other study ID # |
1003 |
Secondary ID |
|
Status |
Active, not recruiting |
Phase |
|
First received |
|
Last updated |
|
Start date |
June 1988 |
Est. completion date |
October 31, 2024 |
Study information
Verified date |
April 2024 |
Source |
National Heart, Lung, and Blood Institute (NHLBI) |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Observational
|
Clinical Trial Summary
To determine the extent to which known risk factors predict coronary heart disease and stroke
in the elderly, to assess the precipitants of coronary heart disease and stroke in the
elderly, and to identify the predictors of mortality and functional impairments in clinical
coronary disease or stroke.
Description:
BACKGROUND:
In 1984, there were an estimated 28 million Americans ages 65 and over of whom 11 million
were ages 75 and over. Projected growth in both the numbers and proportion of the elderly
population in the United States showed marked increases, attributed primarily to declines in
death rates from cardiovascular and non-cardiovascular diseases.
Although there has been a decline in the cardiovascular diseases over the past twenty years,
they are still a major source of morbidity and mortality for middle-aged and older
populations. An estimated 2.8 million persons in the United States ages 65 years and over
have coronary heart disease based on the 1982 National Health Interview Survey of the
National Center for Health Statistics (NCHS). About 1.4 million are men and 1.4 million are
women. Prevalence of coronary heart disease is 11 percent in this age group: 13 percent in
men, 9 percent in women, 12 percent in whites, and 13 percent in Blacks.
The characteristics of increased blood pressure and serum cholesterol, cigarette smoking,
overweight, and diabetes have been documented as risk factors for cardiovascular disease
among men and women in their middle years. A few studies have found that some of these
characteristics operate as risk factors in older populations whereas the role of cigarette
smoking and cholesterol is uncertain. The influence of hemostatic factors remains to be
determined. The traditional risk factors are present in a substantial proportion of the
elderly population. From the 1983 National Health Interview Survey, it is estimated that 21
percent of persons 65-74 years of age are current cigarette smokers. From the 1976-80
National Health and Nutrition Examination Survey of NCHS, it is estimated that 29 percent of
persons 65-74 years of age are overweight, and 28 percent have a serum cholesterol level of
260 mg/100 ml or greater. From the SHEP pilot study, an estimated 68 percent of persons 65-74
years of age and 75 percent of persons ages 75 and over have hypertension, that is, systolic
blood pressure of 160 mmHg or greater or a diastolic pressure of 90 or greater (based on
average of three measurements) or are on anti-hypertensive medication. Isolated systolic
hypertension is quite common in the elderly population.
The Framingham Heart Study observed an average annual incidence of new coronary heart disease
events of 20.4 per 1,000 men ages 65-74 years and 14.5 per 1,100 women in that age group,
based on 20 years of follow-up. The Study has shown a marked increase in incidence with age
and significant physical disability from cardiovascular diseases in the elderly.
Another indication of the impact coronary heart disease has on the elderly in the United
States is health care expenditures. Incidence, prevalence, and disability from heart disease
accounted for personal health care expenditures of $8.2 billion for persons 65 years of age
and older in 1980 according to the National Center for Health Statistics. Based on estimated
expenditures for 1983, that figure was nearly $12 billion in that year. These expenditures
are for hospital care, physician and other professional care, drugs, and nursing home care.
Characteristically, older people have been limited by chronic illness, increasing disability,
and decreased function. As more people reach older ages, there are increasing demands and
expectations for a more functional life and active retirement. Data, however, are relatively
sparse as to the prognostic characteristics, effects of medical care, and ultimate outcomes
of cardiovascular disease in this population. Particular attention will be given to the
accuracy of diagnosis in this elderly population. The use of medical care services by the
elderly and the frequency and nature of pharmacologic, surgical and medical management of
elderly patients will documented. In addition, this study will supply information on the
place of death, suddenness of death and the circumstances preceding clinical events and death
in the elderly.
The study grew out of recommendations of the Working Conference on Coronary Heart Disease in
the Elderly held in Bethesda, Maryland in September 1985 and was reviewed and approved by the
National Heart, Lung, and Blood Advisory Council in September 1986.
DESIGN NARRATIVE:
The Cardiovascular Health Study (CHS) is a population-based, longitudinal study of risk
factors for the development and progression of CHD and stroke in adults aged 65 years or
older. Initially funded for six years, the study has been renewed multiple times and is
currently funded through October 2024.
Within a population of men and women 65 years and older, the objectives of the Cardiovascular
Health Study are:
1. To quantify associations of conventional and hypothesized risk factors with CHD and
stroke.
2. To assess the associations of non-invasive measures of subclinical disease with the
incidence of CHD and stroke.
3. To quantify the associations of risk factors with subclinical disease.
4. To characterize the natural history of CHD and stroke, and identify factors associated
with clinical course.
5. To describe the prevalence and distributions of risk factors, non-invasive measures of
subclinical disease, and clinical CHD and stroke.
This is the most extensive study undertaken by the NHLBI to study CVD exclusively in an
elderly population. It originated from the recommendations of an NHLBI workshop on the
management of CHD in the elderly. Since atherosclerosis is prevalent in the elderly, the
study is focused on factors thought to induce clinically overt disease.
A major emphasis of the study is its focus on subclinical disease, or abnormalities detected
noninvasively without signs or symptoms. Subclinical disease measures in CHS include
ultrasonography of the carotid artery and abdominal aorta, ankle-brachial index,
echocardiography, resting and ambulatory electrocardiography, cerebral magnetic resonance
imaging, spirometry, and retinal photography. Some of these measures were conducted three
times; at baseline, to assess risk of clinical disease in relationship to subclinical
disease; three to four years after entry to assess change in subclinical disease and risk of
clinical disease in relationship to change; and later in the study, to assess predictors of
subclinical disease itself. Echocardiography, ambulatory ECG, cerebral MRI and aortic
ultrasonography were only conducted twice.
The study initially involved four field centers; a coordinating center; a central blood
analysis laboratory and five reading centers including an echocardiography reading center, an
ultrasound reading center, a cerebral MRI reading center, and a retinal reading center. The
reading centers have since been closed out but the field centers, coordinating center and
blood laboratory are still active. Protocol development began in June, 1988, and recruitment
for the first clinical examination began in June, 1989. Examination of 5,201 participants
(2,962 women and 2,239 men) was completed in May, 1990. Two brief interim examinations were
conducted during 1990-1992. A more extensive clinical examination in 1992-1993 was repeated
to assess change in major subclinical disease; at that time, an additional cohort of 672
African Americans was recruited to improve minority representation and assessment of
black-white differences. Between 1993 and 1999, annual examinations focused on a different
major non-invasive measure each time, to reduce participant burden.
Project Status:
Clinic examinations were completed in June 1999. The cohort will continue to be followed with
bi-annual phone calls through 2023. Study endpoints, including: myocardial infarction (MI),
stroke, congestive heart failure, peripheral claudication, angina, and TIA were adjudicated
through June 2015. Death will continue to be adjudicated through the end of the study. CHS
investigators will also continue analyses of previously collected serum and DNA samples;
analyses of recently collected cross-sectional data and analyses of longitudinal data.