Be Wary of Mixing Race and Medicine

Population genomics is making rapid and remarkable advances in detailing the specific genetic variations that characterize ­people in different parts of the world. This information could provide, among other things, invaluable clues to why some medicines are more effective for particular ethnic groups. The worry is that genomic differences between groups will be misunderstood, and perhaps misused, to justify crude generalizations about races.

BiDil, a new heart failure drug that will be marketed to African Americans, doesn’t help. By most estimates, it is an important medicine for heart failure, a disease that has reached epidemic levels in the United States. A clinical trial completed last year found that the pill reduced mortality among African Americans with heart failure by an astounding 43 percent. That’s great news for patients and cardiologists. And the drug has gained the backing of prominent medical groups such as the Association of Black Cardiologists. But if the U.S. Food and Drug Administration approves a race-specific pill, which it could do by mid-year, it will send a confusing message about what researchers are learning from population genomics—and raise troubling questions about how drug developers and physicians will use their growing knowledge of group differences.

As our feature “Race and Medicine” (p. 60) explains, much of the controversy is over the validity of using race as a shortcut to more biologically exact categories. Critics of BiDil point out that conventional racial groups are socially constructed categories that may have little relationship to genetic populations. Such cate­gories are an uncertain guide to predicting which patients a drug will benefit, and using them as such ignores the complex lessons of population genomics. While tests done in the 1980s and early 1990s suggested that the treatment that would later become BiDil was, on average, more effective for black patients than it was for whites, the pill has not been tested in a large study of an ethnically diverse population taking current heart failure medicines. This matters because the reason for the racial differences in the earlier studies is not known. Without that knowledge, it is not possible to specify more precisely which individual patients, black or white, the drug will actually help.