Genetic Discovery Shows Racial Differences a Factor in Mortality in Heart Attack Patients on Anti-Clotting Drug

Kristina Sauerwein, Medical Xpress, June 18, 2014

Researchers have identified the first genetic variations linked to race that begin to explain a higher risk of death among some African American and Caucasian patients taking the anti-clotting drug clopidogrel (Plavix) after a heart attack.

These variants increased patients’ risk of dying in the year following a first heart attack, but they appeared to do so for different reasons depending on race, according to a study at Washington University School of Medicine in St. Louis.

In particular, the team found that two DNA variants common in African Americans were associated with an increased risk of both bleeding and death. In Caucasians, a different variant was linked to additional heart attacks and a higher risk of death.

The research is published June 17 in the American Heart Association journal Circulation: Cardiovascular Genetics.

The variations influence the way people metabolize clopidogrel and can alter its effectiveness. The blood-thinning drug commonly is prescribed after a heart attack to reduce the likelihood of another heart attack or a stroke.

“The research is provocative,” said the study’s first author, cardiologist Sharon Cresci, MD, assistant professor of medicine and of genetics. “Knowing about potential genetic differences based on race can help physicians tailor drugs to patients based on their genetic makeup.”

Clopidogrel is metabolized in the liver, where it is turned into its active form via a group of enzymes called cytochrome P450, or CYP for short. Although clopidogrel is effective in many patients, earlier studies determined that some people metabolize the drug better than others.

Indeed, in 2010, the Food and Drug Administration added a “black box” warning to labels of clopidogrel after research that primarily involved Caucasians showed that people with a particular CYP genetic variant metabolized the drug poorly, which reduced the amount of the drug circulating in the blood. These patients had a higher risk of heart attack and stroke.

Additional studies showed that other CYP gene variants are linked to the rapid metabolism of clopidogrel and that patients with those variants had a higher risk of bleeding.

{snip}

For the study, the researchers analyzed CYP variants among 2,062 Caucasians and 670 African Americans who suffered heart attacks. Nearly 80 percent of the Caucasians and 65 percent of the African Americans were prescribed clopidogrel. {snip}

Among patients taking clopidogrel, the one-year mortality rate for African Americans was 7.2 percent, compared with 3.6 percent for Caucasians.

Caucasians who carried the CYP2C19*2 variant, which has been linked to poor metabolism of the drug, had a higher rate of repeat heart attacks and death. {snip}

However, among African Americans treated with clopidogrel, the CYP2C19*2 variant was not associated with a higher rate of death.

Rather, African Americans had higher rates of bleeding and death if they carried either of two other variants: CYP1A2*1C or CYP2C19*17, the latter of which has been associated with the rapid metabolism of clopidogrel. Among Caucasians on clopidogrel, neither variant increased the risk of death.

{snip}

Although genetic testing is available to identify CYP variants in a patient’s DNA, these tests generally are not widely used by cardiologists. Results of the current study suggest this practice may need to be reconsidered.

{snip}

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  • MekongDelta69

    Anything which may reflect negatively in any way against blacks – however factual – is considered ‘provocative.’

    • LHathaway

      No, this will reflect negatively against whites. The take away will be that whites don’t spend enough time and effort on improving the health of people of color. Never mind that they health care field is discriminating as much as they can against whites, and all of the admin of these organizations is as ‘feminine’ and dark as possible. Sometimes race is a social construct, sometimes, when it comes time to lay blame, race is very real.

  • Einsatzgrenadier

    Science will never convince race deniers because they do not care about the scientific merits of their beliefs. Although they deny the reality of race, the great irony is that they are just as racially motivated as those who seek to preserve white racial integrity. Race deniers are driven towards the achievement of a single goal: the destruction of the white race in Europe and North America. Race denial is just a weapon used by non-European ethnoracial groups and the white destroyers of western culture to undermine white racial integrity. Where there is no white racial consciousness, there can be no resistance to race replacement and miscegenation. Race deniers will say that all races are mixed or argue that there are no pure races, but the purpose of this to further race mixture. As far as they’re concerned, heart attacks are socially constructed and anti-clotting drugs are relative. Everything is an illusion. If you think something is a certain way, it will be that way. The power of thinking makes it so. However, we must never forget that those who embrace this way of thinking are racial nihilists who seek the total dispossession and destruction of the white race.

  • dd121

    Is this gal saying there may be genetic differences among the races that affect medical outcomes? Say it ain’t so. /sarc

  • IKUredux

    Obviously, this entire article is nothing more than a “social construct”. Medication is a “social construct”. Gravity is a “social construct” and harder on women, children, and minorities.

  • MooTieFighter

    Genetic studies have been used for years in medicine. This is not new. The first and second line in blood pressure medicines are often chosen based on race. This is not new in any way; however, if you ever try to tell a white deprecating lib that we are genetically different they will deny it till the end.

  • ElComadreja

    But aren’t we all alike? Just look at the prognathous jaws and pronounced sagittal keel of the negro for proof positive.