The current recommended threshold predicts the risk of heart disease with reasonable accuracy in white people, but underestimates the risk in people of south Asian and African origin.
Researchers identified 1,069 men and women from nine general practices in south London. All participants were aged 40-59 years, 404 were white, 342 were south Asian, and 323 were of African origin.
They used a standard risk threshold of 15% to compare the ten year risk of coronary heart disease (CHD), stroke, and combined cardiovascular disease (CVD). This threshold identifies 91% of white people, but only 81% of south Asians and people of African origin for blood pressure treatment.
After adjusting for age and sex, the estimated 10 year risk of CHD varied significantly by ethnic group. South Asians had the greatest risk of CHD and combined CVD, whereas people of African origin had the lowest. However, people of African origin had the highest risk of stroke.
These results imply that we should be using lower thresholds of CHD risk when treating raised blood pressure in people of African or south Asian origin, say the authors. Using thresholds of 12% in south Asians and 10% in people of African origin would increase the probability of identifying those at risk to 100% and 97% respectively. Risk of CVD would be an even better measurement, they conclude.