Heart Disease Studies Examine Racial Response to Drugs
Today's New England Journal of Medicine features two studies analyzing racial differences in patient response to specific ACE inhibitors and beta blockers. The first study examined responses of black and white patients with left ventricular dysfunction to enalapril, an ACE inhibitor. The study analyzed 1,196 white patients and 800 black patients who participated in prevention and treatment trials comparing enalapril to a placebo. Researchers matched four white patients to each black patient based on age, sex and treatment assignment. Even though matched patients had "similar demographic and clinical characteristics," in white patients, enalapril therapy resulted in a 44% reduction in the risk of hospitalization due to heart failure but prompted "no significant reduction" among black patients, researchers found. In addition, the drug was linked with "significant reductions" in systolic and diastolic blood pressure among whites but not among blacks.
Researchers said that diet, compliance and access to care could contribute to the discrepancies, adding that "racial categorization is only a surrogate marker for genetic or other factors responsible for individual responses to therapy." Additional research addressing the "efficacy of therapies for heart failure in black patients" is necessary, the researchers determined (Exner et al., New England Journal of Medicine, 5/3).
In the second study, researchers analyzed racial differences in patient response to the beta blocker, carvedilol. In the study, 217 black and 877 non-black participants with heart failure received either carvedilol or a placebo twice per day for up to 15 months. Researchers found that carvedilol lowered the risk of death "from any cause" or hospitalization "for any reason" by 48% in black patients and 30% in non-black patients. In addition, carvedilol reduced the risk of "worsening heart failure" -- heart failure that leads to death, hospitalization or a "sustained increase" in medication --by 54% in black patients and 51% in non-black patients. The drug also improved "functional class, ejection fraction and the patients' and physicians' global assessments" in patients from both groups, leading the researchers to conclude that the benefits of the drug were "apparent and of similar magnitude in both black and non-black patients with heart failure" (Yancy et al., New England Journal of Medicine, 5/3).