Major clinical studies that evaluate prevention strategies for heart disease and stroke fail to consider a participant's ethnicity, a factor that can more than double the rate of death in some groups, according to research led by St. Michael's Dr. Joel Ray.

The study, published online in the Quarterly Journal of Medicine, reviewed 45 major clinical trials on prevention strategies. Researchers found that only 1 in 4 studies reported on the ethnicity of participants. None included information about whether a participant was an immigrant. When ethnicity is reported, it is often superficial in scope.

"On the one hand, some immigrant groups to Canada have lower rates of chronic diseases than Canadian-born residents," Ray explains. "But, at the same time, some ethnic groups — like those from South Asia, including India and Pakistan — have dramatic early onset of heart disease and stroke. And, not all ethnic groups respond to preventive treatments in the same manner, such blood pressure medications among persons of Afro-Caribbean decent."

In Canada, 17 per cent of citizens are of a visible minority. Heart disease costs accounts for 17 per cent of hospitalizations each year. Rates of heart disease and stroke are highest among South Asians, one of the largest and fastest growing ethnic groups in Canada, the USA and the U.K. South Asian immigrants have up to a four times higher risk of death from heart disease compared to native-born populations.

"This makes it important to consider ethnicity when conducting research studies so that we can better target prevention strategies to different ethnic groups," says Ray.

The researchers say some ethnic groups may also be reluctant to enrol in clinical trials because consent forms tend to be in English and French. Others may shy away from committing to participating in research because of cultural norms, they add.

"Most of our scientific research on heart disease and prevention stems from studies conducted in the industrialized world, and among predominantly White populations," Ray said. "Future studies must both recruit and report on ethnic and immigrant status of their study groups to ensure we are treating these patients in the best way possible. This must become a priority concept for researchers and funding agencies such as the Canadian Institutes of Health Research and the Heart and Stroke Foundation of Canada."