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African American Health

Clinical Trial Diversity: The Need and the Challenge

Clinical trials (also called medical research and research studies) are used to determine whether new drugs/treatments are both safe and effective. In addition, they help researchers decide if a drug's risks are worth its benefits (risk/benefit ratio). The Food and Drug Administration (FDA) considers the results from clinical trials in approving a drug or treatment. Once approved, the therapy becomes available for doctors to prescribe to their patients.

New therapies are tested on people in clinical trials only after laboratory and animal studies show promising results. It is a challenge for researchers to recruit adequate numbers of clinical trial participants, and even more of a challenge to recruit African Americans. This is a concern because there is evidence that certain drugs have different effects on African Americans than they do on Caucasians.  This article addresses the following questions:

  1. Why don't more African Americans participate in clinical trials?
  2. How can a person be sure that a clinical trial is safe?
  3. Does drug effectiveness vary across races?
  4. How can I participate in a clinical trial?
  5. What questions should I ask before participating in a clinical trial?

Why don't more African Americans participate in clinical trials?

There is a general distrust of the medical/healthcare system amongst some African Americans, and perhaps many, based on personal experience. In addition, historical events have given African Americans reason to mistrust clinical trials.

On July 26, 1972, the New York Times reported on what it called the "longest running non-therapeutic experiment on human beings in medical history." Departing from their Hippocratic Oath to "first, do no harm," physicians from the U.S. Public Health Service allowed nearly 400 poor, black sharecroppers with syphilis to go untreated for forty years. These men from Macon County, Alabama were told they were being treated for "bad blood." However, they were all actually part of the Tuskegee Experiment, which was designed to study the progression of syphilis-a potentially fatal sexually transmitted disease.

Many health professionals and leaders in the black community cite the Tuskegee Experiment as a factor contributing to low participation of African Americans in routine preventive care, clinical trials, and organ donation. However, we can be thankful that the Tuskegee Experiment did lead to a change for the better in how medical research is done. 

How can a person be sure that a clinical trial is safe? 

Does drug effectiveness vary across races?

There are many therapies to which African Americans are known to respond differently than whites.1, 2 For example, some drugs are less effective in African Americans (such as beta blockers for hypertension), some cause increased adverse events (such as occurrence of angioedema with use of ACE inhibitors), and some show both types of differences. 1, 2

One study 3 showed that although ACE inhibitors are particularly effective in whites, but not African Americans. A combination of hydralazine plus isosorbide dinitrate reduced the mortality of black patients. At the same time, white patients given this combination of drugs showed no difference from placebo (sugar pill). The study concluded that clinical trials involving large numbers of black patients are needed to further clarify their response to therapy.

Another study compared enalapril therapy for heart failure among blacks and whites.4 Enalapril therapy reduced the risk of hospitalization for heart failure among white patients with left ventricular dysfunction, but not among similar black patients. Again, the researchers concluded that their findings underscored the need for additional research on the efficacy of therapies for heart failure in black patients. 

How can I participate in a clinical trial? 

Not all studies involve drugs; some long-term studies will only ask you to have a physical and fill out some paper work every few years. Other studies need "controls"-people who don't receive the treatment so the results of those receiving treatment can be compared with them. You have the right to quit any study you become involved in at any time. 

What questions should I ask before participating in a clinical trial? 

If you want to become part of a clinical trial, ask questions about the risks and benefits of the study.

1 Levy, Richard A, ed., Ethnic & racial differences in response to medicines : preserving individualized therapy in managed pharmaceutical programs, Reston, VA: National Pharmaceutical Council, 1993

2 Kalow W., "Interethnic variation of drug metabolism." Trends Pharmacol Sci. 1991 Mar; 12(3):102-7.

3 Carson P, Ziesche S, Johnson G, Cohn JN, "Racial differences in response to therapy for heart failure: analysis of the vasodilator-heart failure trials. Vasodilator-Heart Failure Trial Study Group." J Card Fail. 1999 Sep; 5(3):178-87.

A racially diverse, volunteer panel of health and other professionals from throughout Ohio reviewed this document. Panel members offer their perspectives on NetWellness content developed for African Americans prior to posting.

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Last Reviewed: Aug 21, 2009

Kenneth   Davis, Jr, MD, FACS Kenneth Davis, Jr, MD, FACS
Professor of Surgery and Clinical Anesthesia
College of Medicine
University of Cincinnati