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Biomedical subjects

C D Furberg

Publications and source records attributed to C D Furberg.

At least 127 records · Page 7Linked to original sources
PubMed1994

Cardiac arrhythmias on 24-h ambulatory electrocardiography in older women and men: the Cardiovascular Health Study.

OBJECTIVES: This study describes the prevalence and correlates of cardiac arrhythmias in older persons. BACKGROUND: Cardiac arrhythmias are frequent in selected samples of elderly persons, but their prevalence and association with cardiovascular disease and its risk factors have not been examined in a large population-based sample. METHODS: In 1,372 participants in the Cardiovascular Health Study, a population-based study of cardiovascular disease risk factors, 24-h ambulatory electrocardiography was performed. RESULTS: Serious arrhythmias, such as sustained ventricular tachycardia and complete atrioventricular block, were uncommon, but brief episodes of ventricular tachycardia (> or = 3 consecutive ventricular depolarizations) were detected in 4.3% of women and 10.3% of men. Ventricular arrhythmias as a group (excluding ectopic beats < 15/h) were more common in men than in women but were not significantly associated with age. The same patterns were true for bradycardia/conduction blocks. Supraventricular arrhythmias as a group (excluding ectopic beats < 15/h), in contrast, did not differ by gender but were strongly associated with increased age. Multivariate analyses showed associations with arrhythmias to differ by gender, with only one association (increased age and supraventricular arrhythmias) present in both women and men. Ventricular arrhythmias, particularly in men, were associated with a higher prevalence of cardiovascular disease and its risk factors and with subclinical disease, as measured by increased left ventricular mass and impaired left ventricular function. CONCLUSIONS: Arrhythmias are common in the elderly, and their association with cardiovascular disease differs by gender. Although risk related to arrhythmias can only be determined by prospective study, such studies should have adequate power to examine potential gender differences in associations.

Aged↗
PubMed1994

Challenges to the funding of prevention research.

With the dramatic increases in cost and complexity of medical treatment over the past few decades, the public has emphasized the need to increase efforts aimed at the primary prevention of major causes of illness and death. Screening, early detection, and preventive measures have become attractive alternatives to heroic treatment efforts that exhaust huge resources on the late stages of disease. A large number of research projects have demonstrated substantial public health benefits from preventive measures. While much more prevention research is needed, it is important to bear in mind that the answers to promising research questions are limited by a shortage of funding. The costly nature of prevention research in particular is a roadblock to funding. Due to the current organization of the National Institutes of Health, research in prevention often receives low priority. It is also increasingly apparent that coordination of the national research agenda for disease prevention needs to be better structured. This paper highlights a number of issues that need to be addressed in order to strengthen the prevention research program.

Humans↗
PubMed1994

Lipid-lowering trials: results and limitations.

Because the accumulation of lipids is central to the development and progression of coronary atherosclerosis, interventions (drugs, diet, or surgery) designed to reduce serum cholesterol levels have been tested in a large number of clinical trials, which began in the early 1960s. Data from such trials are now available on more than 45,000 participants, most of whom were men. Nevertheless, debate continues regarding the benefits of lipid-lowering therapy, to a large extent because of methodologic limitations that characterized most trials. Despite their limitations, however, the combined data from these trials demonstrate a reduction in incidence of coronary heart disease after a lag time of 2 or more years. This article reviews combined results of lipid-lowering trials based on published and nonpublished meta-analyses.

Coronary Disease↗
PubMed1994

Hypertensive cardiovascular disease and the treatment of hypertension in the elderly.

Hypertension affects most elderly Americans. In eight major randomized, controlled trials evaluating the treatment of hypertension in the elderly, drug therapy for high blood pressure (including isolated systolic hypertension) has been shown to prevent fatal and nonfatal strokes and coronary events. The relative reduction in strokes was greater than that seen in coronary events. An analysis of the combined data shows that the treatment of hypertension in the elderly also reduces mortality from stroke, coronary heart disease, and all causes. All of these major clinical trials used primarily diuretics and beta-blockers. Low-dose diuretics may be superior to beta-blockers in the elderly; however, reliable comparisons of these and other antihypertensive agents in terms of cardiovascular risk reduction are not yet available. Limited comparisons on the efficacy of blood pressure-lowering and patient tolerance characteristics are reviewed.

Cerebrovascular Disorders↗
PubMed1994

Quality control in ultrasound studies on atherosclerosis.

This review discusses the quality control of equipment and technician performance in long term, multicentre trials using ultrasound detection and quantification of atherosclerosis. Examples on how such quality control measures could be implemented are given. Based on our own experience and that of other groups we suggest the following items as being important when planning for quality control in this type of study. 1. Write down the specifications demanded with regard to the ultrasound equipment and reading stations. 2. Compare the commercially available equipment on those characteristics by means of in-vitro and/or in-vivo testing. 3. Select the most suitable equipment for all centres and check it before shipping. 4. Sign a full maintenance agreement for all centres. 5. Evaluate the ultrasound devices and reading stations regularly during the study using phantoms. 6. Train sonographer and readers thoroughly before the start of the study. Certify those who successfully complete the training programme and demonstrate proficiency in scanning or reading. 7. Determine each sonographer's/reader's variability before and repeatedly during the study. Give feedback on performance to the sonographer/reader. 8. Create a regular retraining programme for all sonographers/readers and extend for those with poor performance. 9. Feed all the above information to a Data Quality Control Committee, having the ultimate responsibility for the quality control in the study.

Arteriosclerosis↗
PubMed1994

Overtreatment and undertreatment of hypertension.

Results from a large number of randomized clinical trials document conclusively that treatment of elevated systolic and/or diastolic blood pressure markedly reduces the risk of cardiovascular complications such as stroke and acute myocardial infarction. Detection, treatment and control of hypertension have major public health implications. A review of the literature suggests the existence of both overtreatment (defined as improper or incorrect diagnosis of hypertension, overaggressive and potentially dangerous blood pressure lowering and the use of expensive antihypertensive drugs with unproven mortality/morbidity benefits) and undertreatment (defined as unrecognized, untreated and poorly controlled hypertension). These current major issues in medicine are discussed.

Antihypertensive Agents↗
PubMed1994

Effect of lovastatin on early carotid atherosclerosis and cardiovascular events. Asymptomatic Carotid Artery Progression Study (ACAPS) Research Group.

BACKGROUND: HMG CoA reductase inhibitors (or statins), a new class of lipid-lowering compounds, have raised expectations for more widespread use than that of the older lipid-lowering drugs. Not only are they more effective in lowering LDL cholesterol, but they are better tolerated as well. No data exist concerning the effect of statins on early carotid atherosclerosis and clinical events in men and women who have moderately elevated LDL cholesterol levels but are free of symptomatic cardiovascular disease. METHODS AND RESULTS: Lovastatin (20 to 40 mg/d) or its placebo was evaluated in a double-blind, randomized clinical trial with factorial design along with warfarin (1 mg/d) or its placebo. This report is limited to the lovastatin component of the trial. Daily aspirin (81 mg/d) was recommended for everyone. Enrollment included 919 asymptomatic men and women, 40 to 79 years old, with early carotid atherosclerosis as defined by B-mode ultrasonography and LDL cholesterol between the 60th and 90th percentiles. The 3-year change in mean maximum intimal-medial thickness (IMT) in 12 walls of the carotid arteries was the primary outcome; change in single maximum IMT and incidence of major cardiovascular events were secondary outcomes. LDL cholesterol fell 28%, from 156.6 mg/dL at baseline to 113.1 mg/dL at 6 months (P < .0001), in the lovastatin groups and was largely unchanged in the lovastatin-placebo groups. Among participants not on warfarin, regression of the mean maximum IMT was seen after 12 months in the lovastatin group compared with the placebo group; the 3-year difference was statistically significant (P = .001). A larger favorable effect of lovastatin was observed for the change in single maximum IMT but was not statistically significant (P = .12). Five lovastatin-treated participants suffered major cardiovascular events--coronary heart disease mortality, nonfatal myocardial infarction, or stroke--versus 14 in the lovastatin-placebo groups (P = .04). One lovastatin-treated participant died, compared with eight on lovastatin-placebo (P = .02). CONCLUSIONS: In men and women with moderately elevated LDL cholesterol, lovastatin reverses progression of IMT in the carotid arteries and appears to reduce the risk of major cardiovascular events and mortality. Results from ongoing large-scale clinical trials may further establish the clinical benefit of statins.

Adult↗
PubMed1994

Spatial distribution of carotid intimal-medial thickness as measured by B-mode ultrasonography.

BACKGROUND AND PURPOSE: Measurements of intimal-medial thickness (IMT) of the carotid artery by B-mode ultrasonography are widely used as markers of atherosclerosis. This report describes empirical features of these measurements to characterize their distribution within arterial wall segments, to explore their potential as study outcome measures, and to examine their links with traditional risk factors for cardiovascular disease. METHODS: Sequential transverse measurements of IMT in the carotid arteries were made in 899 participants from the Asymptomatic Carotid Artery Progression Study (ACAPS) at baseline. Data from 17 intrasegment sites in each of 12 arterial wall segments were used to describe patterns of thickness and visualization and to characterize cross-sectional area, severity, and roughness/irregularity by the intrasegment averages, maxima, and SDs of IMT, respectively. RESULTS: Serial correlations of IMT measurements indicated localized and diffuse features of disease. The spatial distribution of IMT had two dominant features: overall mass and mass relative to roughness. The validity of these features was demonstrated by their correlation to known risk factors for carotid atherosclerosis: body mass index, age, high-density lipoprotein cholesterol, systolic blood pressure, smoking, and sex. CONCLUSIONS: Both the mean and maxima of intrasegment measurements appear to be good candidates for use in clinical studies. B-mode ultrasonography has validity for the description of IMT roughness and shape. Both of these features are linked to cardiovascular risk factors, which supports the multifaceted nature of atherosclerosis.

Adult↗
PubMed1993

Effects of prophylactic antiarrhythmic drug therapy in acute myocardial infarction. An overview of results from randomized controlled trials.

OBJECTIVE: To investigate the effects of prophylactic therapy with antiarrhythmic agents on mortality in patients with myocardial infarction. DATA SOURCES AND STUDY SELECTION: Data were obtained from all completed, published or unpublished, randomized, parallel controlled trials of antiarrhythmic agents, regardless of sample size. Investigators were contacted for data on patients excluded after randomization. DATA EXTRACTION: Data on mortality were extracted by one author and confirmed where necessary by the others. DATA SYNTHESIS: Mortality data from 138 trials on 98,000 patients were combined by the Yusuf-Peto adaptation of the Mantel-Haenszel method. There were 660 deaths among 11,712 patients allocated to receive class I agents and 571 deaths among 11,517 corresponding control patients (51 trials: odds ratio [OR], 1.14; 95% confidence interval [CI], 1.01 to 1.28; P = .03). Of 26,973 patients allocated to receive beta-blockers (class II agents), 1464 died compared with 1727 deaths among 26,295 control patients (55 trials: OR, 0.81; 95% CI, 0.75 to 0.87; P = .00001). Of 778 patients allocated to receive amiodarone (a class III agent), 77 died compared with 101 deaths in 779 control patients (eight trials: OR, 0.71; 95% CI, 0.51 to 0.97; P = .03). There were 982 deaths in 10,154 patients allocated to receive a class IV agent (calcium channel blockers) and 949 deaths in 10,188 control patients (24 trials: OR, 1.04; 95% CI, 0.95 to 1.14; P = .41). CONCLUSIONS: The routine use of class I antiarrhythmic agents after myocardial infarction is associated with increased mortality. beta-Blockers have been conclusively demonstrated to reduce mortality. The limited data on amiodarone appear promising. Data on calcium channel blockers remain unpromising.

Anti-Arrhythmia Agents↗
PubMed1993

Calcium antagonists and atherosclerosis. The Multicenter Isradipine/Diuretic Atherosclerosis Study.

The Multicenter Isradipine/Diuretic Atherosclerosis Study (MIDAS) is a double-blind, randomized, controlled clinical trial comparing the effects of isradipine and hydrochlorothiazide on the progression or regression of early carotid atherosclerosis in 883 hypertensive patients. Assessment of the outcome is by B-mode ultrasonographic measurement of early lesions (as reflected by intimal-medial wall thickening) at baseline and semiannually over 36 months. At baseline, the participants' mean age was 58.5 years. The study population was 78.6% male and 72.4% white. The average resting systolic and diastolic blood pressures were 149.8 and 96.5 mm Hg, respectively. Mean total serum cholesterol and low-density lipoprotein (LDL)-cholesterol levels were 216.2 mg/dL and 146.6 mg/dL, respectively. Risk factors for coronary artery disease were balanced at baseline between the two study groups. The mean maximum intimal-medial thickness at baseline (measured in the near and far walls of three segments for both carotid arteries) was 1.17 +/- 0.20 mm; the mean intimal-medial thickness of the single thickest lesion was 2.11 +/- 0.51 mm. Cross-sectional analyses show that intimal-medial thickness correlates independently with male gender, age, number of cigarettes smoked per day, levels of LDL cholesterol, systolic blood pressure, and white blood cell count. The MIDAS endpoint results will be available in 1993.

Adult↗
PubMed1993

Associations of postmenopausal estrogen use with cardiovascular disease and its risk factors in older women. The CHS Collaborative Research Group.

BACKGROUND: Postmenopausal estrogen replacement therapy has been associated with favorable levels of cardiovascular disease risk factors, but these associations and the relations between estrogen use and subclinical disease have not been examined in large samples of older women. METHODS AND RESULTS: Present and past estrogen use was ascertained in 2955 women > or = 65 years old in the Cardiovascular Health Study, a study of risk factors for coronary heart disease and stroke in the elderly. Present estrogen use was reported by 12% of these women and past use by an additional 26.5%. Estrogen use (past or present) was strongly associated with lower low-density lipoprotein cholesterol, fibrinogen, glucose, insulin, obesity, and age and higher high-density lipoprotein cholesterol and socioeconomic status (all P < .0001). Estrogen users also had lower levels of subclinical disease as measured by carotid intimal-medial thickness, carotid stenosis grade, ECG left ventricular mass, and Doppler mitral peak flow velocities (each P < .02). Relations were similar in younger and older women (65 to 74 versus > or = 75 years) and smokers and nonsmokers and were unchanged after women with poor medication compliance were excluded. After adjustment for other factors, estrogen use was associated with decreased carotid wall thickness, although this association was of borderline significance after further adjustment for lipids. CONCLUSIONS: Postmenopausal estrogen use in this sample of older women was associated with favorable cardiovascular disease risk factor profiles and with lower measures of subclinical disease. These findings suggest that postmenopausal estrogen use may be associated with lower risk of cardiovascular disease in women well into the eighth decade of life.

Aged↗
PubMed1993

Methodological issues facing studies of atherosclerotic change.

BACKGROUND: The association between coronary heart disease and lesions of the coronary arteries has led to investigations of different interventions on atherosclerotic change. Currently, B-mode ultrasound of the peripheral arterial vessels, rather than arteriography of the coronary arteries, provides the most accurate evaluation of atherosclerotic disease extent in the patient. METHODS AND RESULTS: When measuring the effect of risk factor modification on atherosclerotic change, it is important to select appropriate methods and end points for quantifying disease and evaluating subsequent change. Measurements must be valid, precise, and reliable and require appropriate a priori definitions of end points and their change. Consistent methodology within studies is crucial. Multiple measurements and data reduction methods can increase the efficiency of comparisons and merit careful consideration. Missing data arising from nonvisualization of sites complicate analyses. Identifying both covariates of atherosclerotic change and possible confounding interventions require monitoring biochemical, physiological, and/or clinical variables and making inferences from these. CONCLUSIONS: To strengthen the rationale for use of B-mode ultrasonography in assessing the natural history of atherosclerosis, four methodological issues must be addressed: evaluation of primary end points using composite and/or individual measurements of atherosclerotic assessment from the carotid arteries, evaluation of new methodology that may allow assessment of the anatomy of specific lesions and/or their potential for rupture, development of methods making complementary use of both angiographic measurements of lumen diameter and ultrasound assessment of the arterial wall, and concrete demonstration of a direct link between increasing intimal-medial thickness and subsequent clinical events. The use of a continuous variable (intimal-medial thickness) in ultrasound studies offers cost/benefit advantages; this methodology continues to evolve.

Arteriosclerosis↗
PubMed1992

Isolated systolic hypertension and subclinical cardiovascular disease in the elderly. Initial findings from the Cardiovascular Health Study.

OBJECTIVE: To assess the association between isolated systolic hypertension (ISH) and subclinical disease in adults aged 65 years and above. DESIGN: Medicare eligibility lists were used to obtain a representative sample of 5201 community-dwelling elderly persons for the Cardiovascular Health Study, a National Heart, Lung, and Blood Institute--sponsored cohort study of risk factors for coronary heart disease and stroke. In this cross-sectional analysis of baseline data, we excluded 3012 participants who were receiving antihypertensive medications, had clinical cardiovascular disease, or had a diastolic blood pressure of at least 90 mm Hg. MAIN OUTCOME MEASURES: For electrocardiogram: myocardial infarction, left ventricular hypertrophy, and left ventricular mass as measures of myocardial damage and strain; for echocardiography: left ventricular mass, fractional shortening, and Doppler flow velocities as measures of cardiac systolic and diastolic function; and for carotid sonography: carotid arterial intima-media thickness as a measure of atherosclerosis. RESULTS: Among the 2189 men and women in this analysis, 195 (9%) had ISH (systolic blood pressure, greater than or equal to 160 mm Hg) and 596 (23%) had borderline ISH (systolic blood pressure, 140 to 159 mm Hg). Systolic blood pressure was associated with myocardial infarction by electrocardiogram (P = .02). Borderline and definite ISH were strongly associated with left ventricular mass (P less than .001). While there was little association with cardiac systolic function, borderline and definite ISH were associated with cardiac diastolic function (P less than .001). Isolated systolic hypertension was also strongly associated with increased intima-media thickness of the carotid artery (P less than .001). CONCLUSIONS: While cohort analyses of future repeated measures will provide a better assessment of risk, both borderline and definite ISH were strongly related to a variety of measures of subclinical disease in elderly men and women.

Aged↗
PubMed1992

Major electrocardiographic abnormalities in persons aged 65 years and older (the Cardiovascular Health Study). Cardiovascular Health Study Collaborative Research Group.

Electrocardiographic abnormalities are often found in older patients, but their prevalence in free-living elderly populations is not well-defined. In addition, the clinical significance of many of these abnormalities is uncertain. The prevalence of major electrocardiographic abnormalities was determined in 5,150 adults aged greater than or equal to 65 years from the Cardiovascular Health Study--a study of risk factors for stroke and coronary heart disease in the elderly. Ventricular conduction defects, major Q/QS waves, left ventricular hypertrophy, isolated major ST-T-wave abnormalities, atrial fibrillation and first-degree atrioventricular block were collectively categorized as major electrocardiographic abnormalities. Prevalence of any major electrocardiographic abnormality was 29% in the entire cohort, 19% among 2,413 participants who reported no history of coronary artery disease or systemic hypertension, and 37% among 2,737 participants with a history of coronary artery disease or hypertension. Prevalence of major electrocardiographic abnormalities was higher in men than in women regardless of history, and tended to increase with age. Major Q/QS waves were found in 5.2%, and more than half were in those who did not report a previous myocardial infarction. Major electrocardiographic abnormalities are common in elderly men and women irrespective of the history of heart disease.

Age Factors↗
PubMed1992

Eligibility for cholesterol referral in community-dwelling older adults. The Cardiovascular Health Study.

OBJECTIVES: To assess the proportion of community-dwelling adults aged 65 years or older who are eligible for referral for lipoprotein analysis and intervention according to the National Cholesterol Education Program (NCEP) guidelines. DESIGN: Cross-sectional study based on examinations and questionnaires collected in 1989 and 1990. SETTING: Four communities in the U.S. in the Cardiovascular Health Study (CHS), a study of risk factors for heart disease and stroke in older adults. PARTICIPANTS: A sample of 4810 men and women ages 65 to 100 randomly selected and recruited from Health Care Financing Administration Medicare eligibility lists for the four communities; not institutionalized, not wheelchair-bound, not currently receiving therapy for cancer, not currently taking lipid-lowering medications, and not having eaten in the preceding 9 hours. MEASUREMENTS: Total cholesterol and lipoprotein analysis measured in all participants. RESULTS: Total cholesterol levels were less than 5.17 mmol/L (200 mg/dL) in 37% of participants, 5.17 to 6.19 mmol/L (200 to 239 mg/dL) in 39%, and 6.20 mmol/L (240 mg/dL) or greater in 24%. Compared with their counterparts, older participants, especially those over 80 years of age, were more likely to have levels below 5.17 mmol/L, as were men, nonwhites, and those with coronary heart disease or two or more coronary heart disease risk factors (P less than 0.008 for all values). Based on this screening measurement, 2174 participants were eligible for lipoprotein analysis, 80% were eligible for dietary or drug therapy using NCEP guidelines. Overall, 46% of CHS participants were eligible for lipoprotein analysis and 36% for intervention by NCEP guidelines, based on a single cholesterol measurement. CONCLUSION: A substantial proportion of older adults in this community sample were eligible for lipoprotein analysis and intervention. Prospective studies of elderly persons are needed to determine the risk for incident coronary heart disease according to NCEP classifications and the benefits of lipid-lowering treatments in persons in this age group so that intervention strategies may best be targeted to an appropriately high-risk group.

Age Factors↗