Clinical Course of Coronary Artery Disease Among Blacks
To determine the clinical course of coronary artery disease among Blacks receiving medical care for symptomatic heart diseases.
|Study Design:||Observational Model: Natural History|
|Study Start Date:||July 1986|
|Estimated Study Completion Date:||March 2001|
The Black population has age-specific all causes mortality rates among adults which are up to 3.5 times higher than for whites. There remains a pressing need to improve detection and treatment of coronary artery disease among Blacks in an attempt to reduce these unfavorable racial differentials. Also, many fundamental advances in our understanding of atherosclerosis have come from the study of geographic pathology - the epidemiologic comparisons of population groups with widely varying distributions of risk factors. Two prominent features of the epidemiology of coronary artery disease among United States Blacks which are fertile grounds for such comparative studies are the high prevalence of hypertension and the increased susceptibility of Black women to this disease. Knowledge gained from these studies can potentially be applied to coronary artery disease in all human population groups, as has been done with work among the Masai, Seventh-Day Adventists, and other groups.
In this longitudinal study, patients were recruited from the adult Emergency Service of Cook County Hospital. Key end-points included: case fatality rates from acute events; long-term survival rates; sudden versus non-sudden death rates; occurrence of first myocardial infarction among patients with new onset angina; functional recovery after myocardial infarction and coronary artery bypass graft. Baseline data were collected in all groups and include: age, sex, education, weight, height, medical history, hyperlipidemia, alcohol and cigarette use, and medications. Both two-dimensional and M-mode echocardiograms were obtained and an exercise test performed. At the time of cardiac catheterization fasting blood samples were drawn for lipid analysis. Bi-plane ventriculography and cineangiography were performed. After discharge, patients returned to the clinic at three-month intervals for up to two years. Analyses were conducted on left ventricular hypertrophy and socioeconomic status as predictors of mortality. The two control groups permitted comparisons of baseline findings and end-points. One hundred and fifty patients from each of the control groups were followed long-term, primarily through surveillance of government vital status records. The study provided data on survival rates, incidence of new events, and mode of death, the roles of sex differences and hypertension in coronary artery disease, and the efficacy of coronary artery bypass surgery.
The study was renewed in FY 1993 to address a series of major questions related to the clinical epidemiology of coronary artery disease among Black women and to continue the on going study involving 2,806 Black men and women who had been enrolled in a hospital-based registry. An examination of the survival patterns and related risk factors in the cohort of 1,559 Black women was the primary focus of this project.
The study was renewed in 1996 to continue to follow the original cohort to examine the interaction of left ventricular hypertrophy (LVH) and mortality risk in the subgroup of patients with coronary heart disease, to investigate further the impact of left ventricular geometry on survival, and to define the prognostic significance of obesity. Also to enroll a new clinical cohort of 5,600 patients, approximately equally divided between Blacks and whites, from Louisiana State University (LSU) Medical Center. The survival patterns of these groups are compared directly, and the contribution of LVH to the Black:white differential estimated. The new cohort serves as a validation sample for the hypotheses derived from the original cohort.