Ischemic heart disease among South Asians with ischaemic stroke in three countries across two continents: the BRAINS study

Background: Ischaemic heart disease (IHD) and cardiometabolic risk factors have been extensively investigated in those of European descent, yet they are more common among South Asians who make up around 20% of the world's population. We explored the differences in IHD and cumulative metabolic profile in South Asians with stroke living in the UK, India and Qatar, compared with white British stroke patients. Methods: The study included first-ever ischemic stroke white British patients and South Asians living in UK, India and Qatar from the ongoing large Bio-Repository of DNA in Stroke (BRAINS) international hospital-based stroke study. Results: We analysed 4359 patients of which 1575 were white British (WB) UK residents, 1135 British South Asians (BSA), 1084 South Asians in India (ISA), and 565 South Asians in Qatar (QSA). Stroke patients from BSA and ISA background had a 9.5% (95%CI: 6.2-12.9, P<0.001) and 15.8% (95%CI: 13.1-28.9, P<0.001) higher prevalence of IHD respectively, compared to WB patients. Adjusting for traditional stroke risk factors, BSA patients continued to display an increased association of IHD compared to WB patients: OR=1.59 (95%CI: 1.25-2.02, P<0.001). Among South Asian ethnicity, compared to ISA, BSA had an almost twice the association of IHD: OR=1.83 (95%CI: 1.37-2.45, P<0.001). The OR for the presence of 2, or >= 3 cumulative cardiometabolic risk factors was 2.55 (95%CI: 2.02-3.23, P<0.001), and 3.86 (95%CI: 3.02-4.95, P<0.001) for South Asians (ISA, BSA, QSA) compared to WB patients, respectively. Conclusion: South Asian ischaemic stroke immigrants have a higher prevalence of IHD as well as more cumulative cardiometabolic risk factors compared to those who remain on the subcontinent. Countries with large immigrant South Asian populations should focus public health campaigns to mitigate their high cardiometabolic risk profiles.