Diane E. Bild

Coronary calcium as a predictor of coronary events in four racial or ethnic groups.

BACKGROUND In white populations, computed tomographic measurements of coronary-artery calcium predict coronary heart disease independently of traditional coronary risk factors. However, it is not known whether coronary-artery calcium predicts coronary heart disease in other racial or ethnic groups. METHODS We collected data on risk factors and performed scanning for coronary calcium in a population-based sample of 6722 men and women, of whom 38.6% were white, 27.6% were black, 21.9% were Hispanic, and 11.9% were Chinese. The study subjects had no clinical cardiovascular disease at entry and were followed for a median of 3.8 years. RESULTS There were 162 coronary events, of which 89 were major events (myocardial infarction or death from coronary heart disease). In comparison with participants with no coronary calcium, the adjusted risk of a coronary event was increased by a factor of 7.73 among participants with coronary calcium scores between 101 and 300 and by a factor of 9.67 among participants with scores above 300 (P<0.001 for both comparisons). Among the four racial and ethnic groups, a doubling of the calcium score increased the risk of a major coronary event by 15 to 35% and the risk of any coronary event by 18 to 39%. The areas under the receiver-operating-characteristic curves for the prediction of both major coronary events and any coronary event were higher when the calcium score was added to the standard risk factors. CONCLUSIONS The coronary calcium score is a strong predictor of incident coronary heart disease and provides predictive information beyond that provided by standard risk factors in four major racial and ethnic groups in the United States. No major differences among racial and ethnic groups in the predictive value of calcium scores were detected.

Prevalence of Hypertrophic Cardiomyopathy in a General Population of Young Adults Echocardiographic Analysis of 4111 Subjects in the CARDIA Study

BACKGROUND Hypertrophic cardiomyopathy (HCM) is a genetically transmitted disease and an important cause of morbidity and sudden cardiac death in young people, including competitive athletes. At present, however, few data exist to estimate the prevalence of this disease in large populations. METHODS AND RESULTS As part of the Coronary Artery Risk Development in (Young) Adults (CARDIA) Study, an epidemiological study of coronary risk factors, 4111 men and women 23 to 35 years of age selected from the general population of four urban centers had technically satisfactory echocardiographic studies during 1987 through 1988. Probable or definite echocardiographic evidence of HCM was present in 7 subjects (0.17%) on the basis of identification of a hypertrophied, nondilated left ventricle and maximal wall thickness > or = 15 mm that were not associated with systemic hypertension. Prevalence in men and women was 0.26:0.09%; in blacks and whites, 0.24:0.10%. Ventricular septal thickness was 15 to 21 mm (mean, 17 mm) in the 7 subjects. Only 1 of the 7 subjects had ever experienced important cardiac symptoms attributable to HCM, had previously been suspected of having cardiovascular disease, or had obstruction to left ventricular outflow; 4 other subjects had relatively mild systolic anterior motion of the mitral valve that was insufficient to produce dynamic basal outflow obstruction. ECGs were abnormal in 5 of the 7 subjects. Five other study subjects had left ventricular wall thicknesses of 15 to 21 mm that were a consequence of systemic hypertension. CONCLUSIONS HCM was present in about 2 of 1000 young adults. These unique population-based data will aid in assessments of the impact of HCM-related mortality and morbidity in the general population and the practicality of screening large populations for HCM, including those comprising competitive athletes.

Coronary Artery Calcium Score and Risk Classification for Coronary Heart Disease Prediction

CONTEXT The coronary artery calcium score (CACS) has been shown to predict future coronary heart disease (CHD) events. However, the extent to which adding CACS to traditional CHD risk factors improves classification of risk is unclear. OBJECTIVE To determine whether adding CACS to a prediction model based on traditional risk factors improves classification of risk. DESIGN, SETTING, AND PARTICIPANTS CACS was measured by computed tomography in 6814 participants from the Multi-Ethnic Study of Atherosclerosis (MESA), a population-based cohort without known cardiovascular disease. Recruitment spanned July 2000 to September 2002; follow-up extended through May 2008. Participants with diabetes were excluded from the primary analysis. Five-year risk estimates for incident CHD were categorized as 0% to less than 3%, 3% to less than 10%, and 10% or more using Cox proportional hazards models. Model 1 used age, sex, tobacco use, systolic blood pressure, antihypertensive medication use, total and high-density lipoprotein cholesterol, and race/ethnicity. Model 2 used these risk factors plus CACS. We calculated the net reclassification improvement and compared the distribution of risk using model 2 vs model 1. MAIN OUTCOME MEASURES Incident CHD events. RESULTS During a median of 5.8 years of follow-up among a final cohort of 5878, 209 CHD events occurred, of which 122 were myocardial infarction, death from CHD, or resuscitated cardiac arrest. Model 2 resulted in significant improvements in risk prediction compared with model 1 (net reclassification improvement = 0.25; 95% confidence interval, 0.16-0.34; P < .001). In model 1, 69% of the cohort was classified in the highest or lowest risk categories compared with 77% in model 2. An additional 23% of those who experienced events were reclassified as high risk, and an additional 13% without events were reclassified as low risk using model 2. CONCLUSION In this multi-ethnic cohort, addition of CACS to a prediction model based on traditional risk factors significantly improved the classification of risk and placed more individuals in the most extreme risk categories.

Surveillance and ascertainment of cardiovascular events: The Cardiovascular Health Study☆

While previous prospective multicenter studies have conducted cardiovascular disease surveillance, few have detailed the techniques relating to the ascertainment of and data collection for events. The Cardiovascular Health Study (CHS) is a population-based study of coronary heart disease and stroke in older adults. This article summarizes the CHS events protocol and describes the methods of surveillance and ascertainment of hospitalized and nonhospitalized events, the use of medical records and other support documents, organizational issues at the field center level, and the classification of events through an adjudication process. We present data on incidence and mortality, the classification of adjudicated events, and the agreement between classification by the Events Subcommittee and the medical records diagnostic codes. The CHS techniques are a successful model for complete ascertainment, investigation, and documentation of events in an older cohort.

Coronary artery calcification compared with carotid intima-media thickness in the prediction of cardiovascular disease incidence: the Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND Coronary artery calcium (CAC) and carotid intima-media thickness (IMT) are noninvasive measures of atherosclerosis that consensus panels have recommended as possible additions to risk factor assessment for predicting the probability of cardiovascular disease (CVD) occurrence. Our objective was to assess whether maximum carotid IMT or CAC (Agatston score) is the better predictor of incident CVD. METHODS A prospective cohort study of subjects aged 45 to 84 years in 4 ethnic groups, who were initially free of CVD (n = 6698) was performed, with standardized carotid IMT and CAC measures at baseline, in 6 field centers of the Multi-Ethnic Study of Atherosclerosis (MESA). The main outcome measure was the risk of incident CVD events (coronary heart disease, stroke, and fatal CVD) over a maximum of 5.3 years of follow-up. RESULTS There were 222 CVD events during follow-up. Coronary artery calcium was associated more strongly than carotid IMT with the risk of incident CVD. After adjustment for each other (CAC score and IMT) and age, race, and sex [corrected], the hazard ratio of CVD increased 2.1-fold (95% confidence interval [CI], 1.8-2.5) for each 1-standard deviation (SD) increment of log-transformed CAC score, vs 1.3-fold (95% CI, 1.1-1.4) for each 1-SD increment of the maximum IMT. For coronary heart disease, the hazard ratios per 1-SD increment increased 2.5-fold (95% CI, 2.1-3.1) for CAC score and 1.2-fold (95% CI, 1.0-1.4) for IMT. A receiver operating characteristic curve analysis also suggested that CAC score was a better predictor of incident CVD than was IMT, with areas under the curve of 0.81 vs 0.78, respectively. CONCLUSION Although whether and how to clinically use bioimaging tests of subclinical atherosclerosis remains a topic of debate, this study found that CAC score is a better predictor of subsequent CVD events than carotid IMT.

Ethnic Differences in Coronary Calcification The Multi-Ethnic Study of Atherosclerosis (MESA)

Background—There is substantial evidence that coronary calcification, a marker for the presence and quantity of coronary atherosclerosis, is higher in US whites than blacks; however, there have been no large population-based studies comparing coronary calcification among US ethnic groups. Methods and Results—Using computed tomography, we measured coronary calcification in 6814 white, black, Hispanic, and Chinese men and women aged 45 to 84 years with no clinical cardiovascular disease who participated in the Multi-Ethnic Study of Atherosclerosis (MESA). The prevalence of coronary calcification (Agatston score >0) in these 4 ethnic groups was 70.4%, 52.1%, 56.5%, and 59.2%, respectively, in men (P<0.001) and 44.6%, 36.5%, 34.9%, and 41.9%, respectively, (P<0.001) in women. After adjustment for age, education, lipids, body mass index, smoking, diabetes, hypertension, treatment for hypercholesterolemia, gender, and scanning center, compared with whites, the relative risks for having coronary calcification were 0.78 (95% CI 0.74 to 0.82) in blacks, 0.85 (95% CI 0.79 to 0.91) in Hispanics, and 0.92 (95% CI 0.85 to 0.99) in Chinese. After similar adjustments, the amount of coronary calcification among those with an Agatston score >0 was greatest among whites, followed by Chinese (77% that of whites; 95% CI 62% to 96%), Hispanics (74%; 95% CI 61% to 90%), and blacks (69%; 95% CI 59% to 80%). Conclusions—We observed ethnic differences in the presence and quantity of coronary calcification that were not explained by coronary risk factors. Identification of the mechanism underlying these differences would further our understanding of the pathophysiology of coronary calcification and its clinical significance. Data on the predictive value of coronary calcium in different ethnic groups are needed.

Trial of calcium to prevent preeclampsia

Background Previous trials have suggested that calcium supplementation during pregnancy may reduce the risk of preeclampsia. However, differences in study design and a low dietary calcium intake in the populations studied limit acceptance of the data. Methods We randomly assigned 4589 healthy nulliparous women who were 13 to 21 weeks pregnant to receive daily treatment with either 2 g of elemental calcium or placebo for the remainder of their pregnancies. Surveillance for preeclampsia was conducted by personnel unaware of treatment-group assignments, using standardized measurements of blood pressure and urinary protein excretion at uniformly scheduled prenatal visits, protocols for monitoring these measurements during the hospitalization for delivery, and reviews of medical records of unscheduled outpatient visits and all hospitalizations. Results Calcium supplementation did not significantly reduce the incidence or severity of preeclampsia or delay its onset. Preeclampsia occurred in 158 of the 2295 wome...

Methods of Assessing Prevalent Cardiovascular Disease in the Cardiovascular Health Study

The objective of this article is to describe the methods of assessing cardiovascular conditions among older adults recruited to the Cardiovascular Health Study (CHS), a cohort study of risk factors for coronary disease and stroke. Medicare eligibility lists from four US communities were used to obtain a representative sample of 5201 community-dwelling elderly, who answered standardized questionnaires and underwent an extensive clinic examination at baseline. For each cardiovascular condition, self-reports were confirmed by components of the baseline examination or, if necessary, by a validation protocol that included either the review of medical records or surveys of treating physicians. Potential underreporting of a condition was detected either by the review of medical records at baseline for other self-reported conditions or, during prospective follow-up, by the investigation of potential incident events. For myocardial infarction, 75.5% of the self-reports in men and 60.6% in women were confirmed. Self-reported congestive heart failure was confirmed in 73.3% of men and 76.6% of women; stroke, in 59.6% of men and 53.8% of women; and transient ischemic attack, in 41.5% of men and 37.0% of women. Underreporting was also common. During prospective follow-up of an average of about 3 years per person, approximately 50% of men and 38% of women were hospitalized or investigated for at least one potential incident event; for each cardiovascular condition, about 1 to 4% of those investigated during prospective follow-up were found to have had the cardiovascular condition prior to entry into the cohort.(ABSTRACT TRUNCATED AT 250 WORDS)

Orthostatic hypotension in older adults. The Cardiovascular Health Study. CHS Collaborative Research Group.

The purpose of the present study was to assess the prevalence of orthostatic hypotension and its associations with demographic characteristics, cardiovascular risk factors and symptomatology, prevalent cardiovascular disease, and selected clinical measurements in the Cardiovascular Health Study, a multicenter, observational, longitudinal study enrolling 5,201 men and women aged 65 years and older at initial examination. Blood pressure measurements were obtained with the subjects in a supine position and after they had been standing for 3 minutes. The prevalence of asymptomatic orthostatic hypotension, defined as 20 mm Hg or greater decrease in systolic or 10 mm Hg or greater decrease in diastolic blood pressure, was 16.2%. This prevalence increased to 18.2% when the definition also included those in whom the procedure was aborted due to dizziness upon standing. The prevalence was higher at successive ages. Orthostatic hypotension was associated significantly with difficulty walking (odds ratio, 1.23; 95% confidence interval, 1.02, 1.46), frequent falls (odds ratio, 1.52; confidence interval, 1.04, 2.22), and histories of myocardial infarction (odds ratio, 1.24; confidence interval, 1.02, 1.50) and transient ischemic attacks (odds ratio, 1.68; confidence interval, 1.12, 2.51). History of stroke, angina pectoris, and diabetes mellitus were not associated significantly with orthostatic hypotension. In addition, orthostatic hypotension was associated with isolated systolic hypertension (odds ratio, 1.35; confidence interval, 1.09, 1.68), major electrocardiographic abnormalities (odds ratio, 1.21; confidence interval, 1.03, 1.42), and the presence of carotid artery stenosis based on ultrasonography (odds ratio, 1.67; confidence interval, 1.23, 2.26). Orthostatic hypotension was negatively associated with weight. We conclude that orthostatic hypotension is common in the elderly and increases with advancing age. It is associated with cardiovascular disease, particularly those manifestations measured objectively, such as carotid stenosis. It is associated also with general neurological symptoms, but this link may not be causal. Differences in prevalence of and associations with orthostatic hypotension in the present study compared with others are largely attributed to differences in population characteristics and methodology.

Lower-Extremity Amputation in People With Diabetes: Epidemiology and Prevention

The age-adjusted rate of lower-extremity amputation (LEA) in the diabetic population is ∼15 times that of the nondiabetic population. Over 50,000 LEAs were performed on individuals with diabetes in the United States in 1985. Among individuals with diabetes, peripheral neuropathy and peripheral vascular disease (PVD) are major predisposing factors for LEA. Lack of adequate foot care and infection are additional risk factors. Several large clinical centers have experienced a 44–85% reduction in the rate of amputations among individuals with diabetes after the implementation of improved foot-careprograms. Programs to reduce amputations among people with diabetes in primarycare settings should identify those at high risk; clinically evaluate individuals to determine specific risk status; ensure appropriate preventive therapy, treatment for foot problems, and follow-up; provide patient education;and, when necessary, refer patients to specialists, including health-care professionals for diagnostic and therapeutic interventions and shoe fitters for proper footwear. Programs should monitor and evaluate their activities andoutcomes. Many issues related to the etiology and prevention of LEAs requirefurther research.