Cardiovascular disease (CVD) and, in particular, coronary heart disease (CHD) remain the leading causes of death in men and women 65 years and older, despite the decline in absolute mortality rates that has been seen in both sexes since 1968 (Feinleib and Gillum, 1986). In women, the prevalence of CHD morbidity has increased, in part as a result of reduced case fatality rates and in part as a result of longer life expectancy (Nickel and Chirikos, 1990). Consequently, women surviving a heart attack may live with the symptoms and functional consequences of their heart disease for many more years. In 1991, more than half of the yearly health care costs related to CVD were for women (Eaker et al., 1993).
Heart disease is also one of the leading causes of disability in women (German and Fried, 1989). In a recent study that asked older participants to assess the condition causing their disability (Ettinger et al., 1994), heart disease ranked second. Its main impact was in the mobility and exercise tolerance domains (Fried et al., 1994), such as walking, climbing stairs, or doing heavy housework. Estimates of the percentage of women with CHD who are disabled by their illness range from 47 percent in women age 65 to 74 years to 55 percent in women age 75 years and older (Soldo and Manton, 1985).
Diabetes mellitus, the sixth leading cause of death among those age 65 and older, affects approximately 10 percent of older women and is an important cause of morbidity and premature mortality (National Diabetes Data Group, 1985). Diabetic patients, especially those in poor metabolic control, are susceptible to a series of long-term micro- and macrovascular complications that can affect every aspect of physical function (Nathan, 1993). Data from the National Health Interview Survey indicate a twofold higher likelihood of self-reported physical limitations in diagnosed diabetics compared with the general U.S. population (Drury, 1985).
As people get older, ascertaining their clinical symptoms does not fully identify the impact of a disease on physical function. Older persons may underreport symptoms related to CVD because they curtail their physical activity to avoid the onset of symptoms or because their physical function is already impaired by other comorbid conditions. In addition, asymptomatic events such as silent myocardial infarctions (Mittelmark et al., 1993) and atypical symptoms (Bayer et al., 1986) are common in older people. Finally, the reporting of symptoms or conditions can be influenced by social, psychological, and cognitive factors (Kukull et al., 1994).
Noninvasive, objective measures of clinical or subclinical disease are therefore vital in estimating the prevalence of cardiovascular diseases in an older population and in fully evaluating the impact of these conditions on physical function (Bild et al., 1993; Kuller et al., 1994). This chapter describes (1) the prevalence of cardiovascular diseases in disabled older women according to both objective examination and self-report of conditions and symptoms and (2) the association of these measures with age and level of disability.
A trained interviewer asked participants whether they were ever told by a doctor that they had angina or chest pain due to heart disease, heart attack or myocardial infarction, congestive heart failure, high blood pressure, rheumatic heart or valvular heart disease, lower extremity arterial disease, or diabetes. The women were also asked whether they had ever had coronary artery bypass surgery or surgery on the arteries of the legs (Table 9.1).
When the total prevalence rates of CVD conditions in the study population (Table 9.1) are compared with prevalence rates in the ineligible population (Chapter 1, Table 1.3), the association between CVD conditions and disability status is evident. The prevalence of these conditions in the study population is two to three times higher than in the ineligible population (Table 1.3).
In the study population, about one in five women reported a history of angina, myocardial infarction, and diabetes, and nearly 60 percent reported high blood pressure (Table 9.1). The proportion of those who reported high blood pressure, diabetes, and heart valve problems tended to decrease with age, with the lowest rates occurring, in general, in participants age 85 years and older. This may be related to selective survival of women without these conditions. Rates of coronary artery bypass surgery also tended to be higher in women age 65 to 74 years than in the oldest old (Table 9.1). Reported rates of congestive heart failure and diabetes were greatest in those receiving help with activities of daily living (ADLs). Rates of coronary artery bypass surgery decreased with increasing severity of disability, from 5.5 percent in women with moderate disability to 0.7 percent in women who received help with ADLs (Table 9.1). This relationship was not seen for lower extremity arterial surgery.
The presence of cardiovascular symptoms, shown in Table 9.2, was determined by the answers to a series of questions. Chest pain was defined as nonexertional if the participant reported any pain or discomfort in her chest and did not report the pain when walking, or did not walk at all. Exertional chest pain was defined as pain or discomfort in the chest that was reported when walking on level ground and/or when walking uphill or hurrying, utilizing the standardized questions from the Rose Questionnaire (Rose, 1962). Orthopnea was assessed by asking the respondent whether she became short of breath at night sleeping flat or on only one pillow. Paroxysmal nocturnal dyspnea was determined by asking the participant whether she woke up at night gasping for breath. Intermittent claudication was ascertained with the Rose Questionnaire (Rose, 1962) and was defined as being present if the participant reported all of the following symptoms: pain in either leg when walking, the localization of the pain in her calf or calves, and the relief of this pain when walking stopped. Ankle swelling was considered present if the respondent reported foot or ankle swelling that developed or worsened during the day and decreased at night.
Clinical symptoms related to cardiovascular diseases tended to be less prevalent among women 85 years and older compared to younger women (Table 9.2), possibly because of selective survival of those without these problems. Interesting patterns of symptoms were seen in relation to level of disability. With increasing severity of disability there was a decrease in exertional chest pain, little difference in intermittent claudication, and a substantial increase in orthopnea or paroxysmal nocturnal dyspnea. The higher rates of exertional chest pain in the least disabled subgroup are probably a result of the fact that less disabled people are more likely to undertake activities that can trigger exercise-related clinical symptoms.
Clinical signs and cardiovascular disease measures were assessed by a trained nurse during the physical examination performed in the participant's home, according to standardized protocols (Table 9.3). The presence of pulmonary rales (defined as bilateral rales that were audible with the stethoscope and did not clear with coughing) increased from 4.1 percent in women age 65 to 74 years to 13.3 percent in those age 85 years and older. Heart sounds were auscultated in a sitting position at Erb's point. Systolic and diastolic murmurs were defined as absent, present, or unknown. Almost one-third (28.9 percent) of women had an audible systolic murmur, a finding that was more common in women age 85 years and older (37 percent).
The prevalence of ankle edema, identified on examination using local pressure on the tibia (Table 9.3), differed from self-reported ankle edema, assessed by history of ankle swelling (Table 9.2). Most notably, ankle edema on exam increased with age, while self-reported ankle swelling decreased with age. Those age 65 to 74 years reported more ankle swelling than was found on exam, while those 85 years and older reported less swelling than was found on exam. A marked increase in ankle edema was observed with increasing level of disability (Table 9.3).
Blood pressure was measured in a semi-recumbent position with the use of a mercury sphygmomanometer and a cuff of appropriate size on the right arm, following the protocol of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (1988). The average of three measurements of the systolic (SBP) and diastolic blood pressure (DBP, recorded at the fifth Korotkoff sound) was used to classify participants into blood pressure categories. The categories were defined, according to the protocol (Joint National Committee, 1988), as follows: normotensive, DBP less than 90 mmHg and SBP less than 140 mmHg; borderline isolated systolic hypertension, DBP of less than 90 mmHg and SBP of 140 to 159 mmHg; isolated systolic hypertension, DBP of less than 90 mmHg and SBP of at least 160 mmHg; diastolic hypertension, DBP of at least 90 mmHg with any systolic blood pressure.
To assess the ankle-arm blood pressure index (AABPI), a standard mercury manometer was used to measure, in rapid succession, the SBP in the right arm and both legs with the subject in a semi-recumbent position. The SBP in the right and left posterior tibial arteries was measured twice using a standard arm blood pressure cuff applied just above the malleoli and an 8-Mhz Doppler stethoscope (Parks Model 841-A). To calculate the AABPI the higher of two SBPs in the left posterior tibial artery was averaged with the higher of two SBPs in the right posterior tibial artery, and the result was divided by the higher of two right brachial artery SBPs, also measured with the Doppler stethoscope (Newman et al., 1993). The ratio was categorized in five groups: less than 0.8, 0.8 to less than 0.9, 0.9 to less than 1.0, 1.0 to 1.5, and greater than 1.5 (Newman et al., 1993).
Blood pressure measurement revealed that the percentage of women with normal blood pressure decreased with increasing age, a result of an increase in the proportion of women with isolated systolic hypertension at older ages (Table 9.3). In contrast to these findings, self-report of high blood pressure (Table 9.1) was less common in women age 85 years and older. More aggressive pharmacologic treatment of high blood pressure in younger women could explain these findings. As severity of disability increased, the percentage of women who were normotensive decreased, a result of modest increases in all three categories of hypertension.
Approximately 12.5 percent of women had an AABPI less than 0.8. This finding was more common in the oldest women (17.5 percent) and in those receiving help in ADLs (14.9 percent). Exercise-induced symptoms, suggestive of intermittent claudication (Table 9.2), were compared with the actual measurement of the AABPI, which allows for a more objective evaluation for the presence of peripheral vascular disease (Table 9.3). Older women reported a lower prevalence of peripheral vascular disease symptoms than the younger participants (Table 9.2), but the proportion of women with an AABPI less than 0.8 was, in fact, higher among women 85 years and older (Table 9.3). In addition, the proportion of women in whom values of AABPI could not be obtained increased with age and disability level. These findings suggest that the prevalence of peripheral arteriopathy is likely to be underestimated in older persons with reduced mobility when the diagnosis relies on symptoms only.
Twelve-lead electrocardiograms (ECGs) were recorded using the MAC PC-DT ECG Recorder (Marquette Electronics Inc., Milwaukee, WI). ECGs were stored electronically and transmitted to a centralized reading center (Epicare) for classification of electrocardiographic abnormalities using the NOVACODE measurement and classification system (Rautaharju et al., 1990).
Exclusion Criteria
Participants with artificial pacemakers (N = 15, 1.1 percent), with missing information on pacemakers (N = 5 , 0.5 percent), and with inadequate quality or no ECG data (N = 29, 2.9 percent) were excluded from this analysis, leaving a total of 953 participants (95 percent) with valid ECG data (Table 9.4). In subjects with major ventricular conduction defects, coding was not done for major Q/QS waves, left ventricular hypertrophy and ST-T wave abnormalities. Similarly, left ventricular hypertrophy and major Q/QS waves precluded coding of ST-T wave abnormalities, and atrial fibrillation or flutter precluded coding of first-degree atrioventricular block.
Classification
Major ECG abnormalities were classified as follows, according to the Minnesota code (Blackburn et al., 1960):
1. Major Q/QS waves (codes 1-1, 1-2 except 1-2- 8)
2. Left ventricular hypertrophy (high amplitude R waves with major or minor ST-T abnormalities, codes 3-1, 3-3 with 4-1 to 4-3, or 5-1 to 5-3)
3. Isolated major ST-T wave abnormalities (codes 4-1, 4-2, 5-1, 5-2 without 3-1, 3-3, 1-1 to 1-3)
4. Atrial fibrillation or atrial flutter (code 8-3)
5. First-degree atrioventricular block (code 6-3)
6. Ventricular conduction defects: left bundle branch block (code 7-1); right bundle branch block (code 7-2); intraventricular block of indeterminate type with QRS interval >= 120 ms (code 7-4)
Electrocardiographic Findings and
Abnormalities
A heart rate less than or equal to 60 was recorded in 18.8 percent of the participants. A heart rate greater than 90 was present in 6.0 percent of the entire population and tended to be more prevalent in women age 65 to 74 years (8.8 percent) and in those receiving help with ADLs (10.4 percent).
Major electrocardiographic abnormalities were common in this cohort of disabled women. Almost one-third (29.2 percent) of the participants had at least one of the six major abnormalities. The prevalence of major Q/QS waves and ventricular conduction defects tended to increase, in general, with age and level of disability, a trend also noted for the presence of any of the six major abnormalities. The prevalence of atrial fibrillation or flutter and left ventricular hypertrophy clearly increased with increasing age, while no consistent association was observed with level of disability. The prevalence of first degree atrioventricular block in the oldest old (8.9 percent ) and in those receiving help with ADLs (10.8 percent) was approximately double the prevalence in those age 65 to 74 years (4.8 percent) and in those with moderate disability (5.1 percent).
These findings reinforce the importance of combining clinical findings and physical assessment to ascertain the presence of diseases in population studies of older persons. In an older and disabled population, this approach is essential not only to validate the presence of the disease, but is potentially important in clarifying the trajectory between preclinical disease, clinical disease, impairment, and disability.
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