Heart attack drug less beneficial for people of Bangladeshi or Pakistani ancestry

A medication commonly prescribed to prevent heart attacks is much less likely to benefit people of Bangladeshi and Pakistani ancestry, compared with those of European descent, a study has found.

The drug clopidogrel is commonly prescribed to patients after a heart attack to prevent further attacks. It works by stopping blood cells known as platelets from sticking together.

This helps to prevent dangerous blood clots from forming. However, clopidogrel needs to be activated in the body to be effective.

Studies of European populations show that 30% of people have changes in their genes, known as genetic variants, that reduce or prevent activation through the production of an enzyme called CYP2C19.

People of South Asian ancestry have high rates of cardiovascular disease. However, researchers have not up to now looked for these variants in UK South Asian populations.

The researchers at Queen Mary University of London examined the health data of 44,396 British people of Bangladeshi and Pakistani ancestry.

They found that 57% of participants have a common genetic change which means they cannot activate the heart attack drug. All study participants were from the Genes & Health cohort, and more than two in three of British South Asians in this cohort who have had a heart attack received clopidogrel.

Using the participants’ long-term health data, the research team was able to show that people with two loss-of-function CYP2C19 variants were more than three times more likely to have recurrent heart attacks. This may be because treatment with clopidogrel doesn’t work for them, they argued.

The study, published in the journal JACC: Advances, was funded by the National Institute for Health and Care Research Barts Biomedical Research Centre and Barts Charity.

The researchers argue their study has highlighted the importance of understanding how treatments affect different ancestral groups. This is key to ensuring that everyone has equal access to effective treatments.

Dr Emma Magavern, lead author and clinical doctor and researcher at Queen Mary University of London, said: “Clopidogrel has been shown to prevent heart attacks mainly in people of European ancestry. For the first time we show that genetic variants that render clopidogrel ineffective are present at much higher rates (57%) in British people of Bangladeshi and Pakistani ancestry and are linked with higher risk of having another heart attack in people prescribed clopidogrel.

“This study highlights the importance of using genetics to determine who can benefit from clopidogrel after a heart attack, and how not doing so is likely to disproportionately disadvantage specific groups, such as South Asians.”