INTRODUCTION

Cardiovascular disease is the leading cause of morbidity and mortality in industrialized societies. The incidence of cardiovascular disorders, including heart attacks, heart failure, and stroke, has been declining steadily over the past 30 years. This decline has been attributed to improvements in understanding and applying preventive and therapeutic strategies to reduce prevalence and improve treatment outcomes in cardiovascular disease.

However, in certain ethnic groups (eg, African American females), this decline has not been noticed; in fact, the reverse has been observed, with an increase in the incidence of these medical conditions. This phenomenon is probably multifactorial, with the increased prevalence of cardiovascular risk factors in certain ethnic groups (compared to their white counterparts) possibly due to undertreatment and barriers to recognition. Regardless of the overall cause, the increased burden of cardiovascular disease in ethnic groups at high risk for cardiovascular disorders warrants more aggressive risk factor modification and treatment intervention. Several studies have now shown that increased use of statins is associated with reduced cardiovascular disease. Although these studies have predominantly involved white persons, the results indicate that increased advocacy for the aggressive use of statins should be strongly considered in members of ethnic groups at high risk for cardiovascular disorders.

EPIDEMIOLOGY

The traditional risk factors for cardiovascular disease include family history, age, hypertension, hypercholesterolemia, smoking, diabetes, male gender, and obesity. Subsequently, additional risk associations have emerged, including metabolic syndrome, atherogenic dyslipidemia, hyperhomocysteinemia, hyperlipoproteinemia a, and C-reactive protein (CRP). The presence of multiple concomitant risk factors greatly increases the risk of cardiovascular disease.

The prevalence of hyperlipidemia in the general population is high; however, awareness and screening remain suboptimal, especially among ethnic subgroups. African Americans and Mexican Americans were less likely than white persons to report having their cholesterol screened in the Third National Health and Nutrition Examination Survey (NHANES III).

Additionally, because of the paucity of large studies specifically addressing ethnic groups at high risk, data have to be extrapolated to ethnic groups or limited to retroactive analysis of subgroups within large databases. Some analyses of ethnic groups in these large databases have shown mixed results, with some demonstrating a lower burden of hyperlipidemia among certain ethnic subgroups compared to others. One such study is the Genetic Epidemiology Network of Arteriopathy (GENOA) study. This study included 1070 non-Hispanic white persons and 1286 non-Hispanic black persons. Dyslipidemia was more common among non-Hispanic white persons than non-Hispanic black persons. Up to 78.4% of non-Hispanic white men had dyslipidemia compared to 49.5% of non-Hispanic black women.

STATIN USE

Several studies have shown the benefits of targeting the modifiable risk factors on improvement in cardiovascular disease outcomes. The treatment of hypercholesterolemia reduces cardiovascular disease burden; this is now well established. Several studies have shown varying degrees of cardiovascular disease risk reduction following reductions in cholesterol levels, particularly total cholesterol levels and LDL cholesterol (LDL-C) subfractions. Improvement in low HDL cholesterol (HDL-C) levels confers additional protection. These benefits are derived at all stages, from prevention to reducing the progression of established cardiovascular disease.

Treatment options for hypercholesterolemia and therapeutic targets have been well detailed by the National Cholesterol Education Program (NCEP) with guidelines established by the Adult Treatment Panel (ATP). These treatment options include lifestyle interventions and pharmacotherapy. Lifestyle interventions target dietary changes, weight loss, and exercise. Pharmacotherapeutic agents include statins as the most efficacious agents to target total cholesterol levels and LDL-C levels. The addition of ezetimibe to statins improves efficacy. Fibrates improve hypertriglyceridemia, while niacin and fish oils improve HDL-C levels.

Available data suggest that, overall, adequately treated hypercholesterolemia in patients is still low and is particularly suboptimal among ethnic minority groups. These studies, however, have not contained substantial representations of ethnic groups at high risk compared to their white counterparts. Among patients at high risk, aggressive reduction of cholesterol levels better improves outcomes compared to less aggressive targeting. In the Treating to New Targets (TNT) study, patients with established cardiovascular disease who also had diabetes experienced a 25% risk reduction in cardiovascular events when treated with atorvastatin 80 mg compared to atorvastatin 10 mg, regardless of baseline LDL-C level.

In the United Kingdom Prospective Diabetes Study (UKPDS), 2999 patients with type 2 diabetes were observed for changes in lipid levels at intervals of 3, 6, and 9 years. The analysis comprised white persons (83%), Afro-Caribbeans (9%), and Asians of Indian origin (8%). All groups showed improvement in total cholesterol levels and LDL-C levels. Afro-Caribbean patients had the most favorable changes in HDL-C levels and plasma triglyceride levels. In the GENOA study, subjects from other ethnic groups were less likely than white persons to report treatment for hyperlipidemia. Only 12.8% of black men and 16.4% of black women were treated, compared with 32.5% and 25.4% of their white cohorts, respectively. The NHANES III study reported that Mexican Americans and African Americans were less likely than whites to be taking a cholesterol-lowering medication when hypercholesterolemia was known to be present.

Differences in response to statin therapy between white persons and other ethnic groups have not been widely reported. As reported on the rosuvastatin package insert that was approved by the US Food and Drug Administration, a pharmacokinetic study that involved Asians living in the United States revealed that drug levels of rosuvastatin were elevated approximately 2-fold in the Asian subjects compared with a Caucasian control group (Crestor, 2005). This reported difference in effect of rosuvastatin among the Asian population underscores the need to reexamine the differences in response to statin use in diverse ethnic groups.

CONCLUSION

A significant need exists to reduce modifiable cardiovascular disease risk factors in the general population and, specifically, in ethnic groups at high risk for cardiovascular disease. Statins offer a proven option to lower cardiovascular disease risk by lowering cholesterol to target levels. Ethnic minorities remain at higher risk of missed diagnosis and undertreatment with resultant poorer outcomes compared to their white counterparts, demonstrating the need for more aggressive use of statins in ethnic groups at high risk for cardiovascular disease.

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