Cardiovascular Risk Profiling in Blacks: Don't Forget the Lipids
Am Fam Physician. 1998 Nov 1;58(7):1541-1542.
As a population, blacks have one of the highest rates of coronary artery disease (CAD) in the world.1 Evidence from the National Hospital Discharge Survey (NHDS) suggests that CAD has an earlier onset and is particularly severe in this group. The median age at death from myocardial infarction is five years lower in blacks than in whites, and the mortality rate is higher in all age groups less than 70 years.2
Are these data surprising? For some of us, the answer is “yes”—we tend to focus on stroke risk in blacks and the linear association with hypertension. Indeed, many of us overlook other risk factors—particularly lipid disorders—because we learned from the National Health and Nutrition Examination Survey database that blacks have higher mean high-density lipoprotein (HDL) cholesterol levels than their white counterparts, despite having similar mean levels of total and low-density lipoprotein (LDL) cholesterol levels.3 Indeed, the control of blood pressure in this population is often so problematic that it dominates our attention during the office visit.
Tragically, identification of hypercholesterolemia, in many instances, is influenced by the race of the patient. Data collected in a Rochester, N.Y., family medicine residency training program4 suggested that, after controlling for age, sex, insurance status, socioeconomic status, number of visits and other cardiovascular risk factors, blacks were less likely than whites to have been screened for cholesterol levels. Among those who were screened and were found to have a cholesterol level greater than 240 mg per dL (6.20 mmol per L), minorities were less likely than whites to receive a diagnosis of hypercholesterolemia.4
While patient awareness and concern about cholesterol have increased, studies suggest that there is less awareness and concern among black patients.5 Results of a study in an inner-city clinic show that almost 50 percent of black patients had hyperlipidemia and were not receiving interventional treatment.6 Similarly, unpublished data from Fong and Ward suggest that over 40 percent of black patients with hypertension who were seen in Rochester, N.Y., had hyperlipidemia. Based on guidelines of the National Cholesterol Education Program II (NCEP II), more than one half of these patients would be candidates for pharmacologic therapy.7
We know less about the effects of the use of inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCoA) in black patients. In the Expanded Clinical Evaluation of Lovastatin (EXCEL) study,8 only 459 of 8,245 patients (5.5 percent) were black. The percentage of involvement of blacks was even lower in the landmark prospective Scandinavian Simvastatin Survival Study (4S) and West of Scotland Study. Clinicians should be aware that there is similar efficacy of “statins” in blacks compared with whites but a higher incidence of creatine kinase levels in the upper limit of normal. In the EXCEL sub-study, there was no increased risk for myopathy or rhabdomyolysis.8
Blacks remain a group at significant risk for CAD. While HDL cholesterol levels appear to be higher in blacks than in whites, elevated total and LDL cholesterol levels still need to be treated in black patients, because we know from the results of the Multiple Risk Factor Intervention Trial9 that elevations of these levels are predictive of coronary events. It remains unclear to what extent HDL confers cardiovascular protection. The higher incidence of CAD and underuse of invasive cardiovascular procedures suggest that more emphasis be placed on risk factor reduction. While more long-term studies in blacks are necessary to show that lowering total LDL cholesterol levels translates into actual reductions in clinical CAD events and mortality reductions, there is enough evidence from other groups to intervene aggressively with dietary and pharmacologic interventions.
This information should serve as a call-to-arms for all physicians, especially those of us in primary care. Make it a point to ask your black patients about a family history of lipid disorders and check lipid profiles according to age guidelines, with special vigilance in those with other cardiovascular risk factors. If you are in a clinic setting, assign a staff member, medical student or resident to review charts to assess compliance with NCEP guidelines in all patients. And, if you are so inclined, participate in clinical trials of cholesterol-lowering agents, enrolling black (and other minority) patients to expand our knowledge base of efficacy and safety of these agents in this population. Unless and until we consciously take these steps, the disparity in identification and treatment of this easily modifiable risk factor will persist.
1. Gillum RF. Coronary heart disease in black populations, I: morbidity and mortality. Am Heart J. 1982;104:839–51.
2. Roig E, Castaner A, Simmons B, Patel R, Ford E, Cooper R. In-hospital mortality rates from acute myocardial infarction by race in U.S. hospitals: findings from the National Hospital Discharge Summary. Circulation. 1987;76:280–8.
3. Linn S, Carroll M, Johnson C, Fulwood R, Kalsbeek WD, Briefel R. High-density lipoprotein cholesterol and alcohol consumption in US white and black adults: data from NHANES II. Am J Public Health. 1993;83:811–6.
4. Naumburg E, Franks P, Bell B, Gold M, Engerman J. Racial differentials in the identification of hypercholesterolemia. J Fam Pract. 1993;36:425–30.
5. Factors related to cholesterol screening and cholesterol level awareness-United States. MMWR Morb Mortal Wkly Rep. 1990;39:633–7.
6. Foster P, Jackson M. Distribution of lipoprotein phenotypes, cholesterol, and lipids in inner-city blacks. J Natl Med Assoc. 1993;85:211–5.
7. National Cholesterol Education Panel. Second report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. JAMA. 1993;269:3015–23.
8. Prisant LM, Downton M, Watkins LO, Schnaper H, Bradford RH, Chremos AN, et al. Efficacy and tolerability of lovastatin in 459 African-Americans with hypercholesterolemia. Am J Cardiol. 1996;78:420–4.
9. Multiple Risk Factor Intervention Group. Risk factor changes and mortality results. JAMA. 1982;248:1465–77.
Copyright © 1998 by the American Academy of Family Physicians.
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