Ischaemic Stroke in South Asians

South Asians make up the largest ethnic minority in the UK, however current research on ischaemic strokes within this demographic is limited. In this thesis, I explored differences in characteristics of ischaemic stroke in South Asians in the UK (BSA), India (ISA), and white British (WB) patients. I undertook a review of the limited literature available in which BSA reported earlier stroke onset compared to the WB population. BSA also presented with an increased mortality rate, and greater prevalence of cardiometabolic risk factors, including hypertension. These studies used small sample sizes while the only study reporting age was conducted +20 years ago.

To answer gaps within the literature I utilised the UK and Indian arms of the ongoing prospective international hospital-based study on South Asian stroke (BRAINS study). This database consists of 1650 BSA (men:1074, women:576), 1279 ISA (men:864, women:415) and 2291 WB (men:1296, women:995) ischaemic stroke patients. Both BSA and ISA suffered from stroke ~7 and ~20 years, respectively, earlier than their WB counterparts (BSA:64.3±15.1 years, vs. ISA:52.0±13.4 years, vs. WB:71.5±13.5 years, P<0.001). I found after adjusting for age, sex, atrial fibrillation, smoking history and central obesity in stepwise logistic regression, there was a ~2-fold increase in small vessel occlusion prevalence (BSA vs WB:1.65, 95%CI:1.15 – 2.38) and a ~30-60% decrease in large artery atherosclerosis (ISA vs WB:1.88, 95%CI: 1.44–2.44) classified stroke in both ISA and BSA, compared to WB patients.

Both BSA (OR=4.87, 95%CI: 3.80–6.25) and ISA (OR=1.96, 95%CI: 1.53–2.51) had an increased risk of having 3+ metabolic risk factors by ~4-6 fold compared to WB patients. BSA has a lower risk of atrial fibrillation compared to their white British counterparts (OR:0.40, 95%CI:0.33-0.49). No ethnic-specific differences were reported in the use of anticoagulation at admission (P=0.93) or discharge (P=0.64).

Based on the results presented in this thesis, prevention and management strategies should consider distinct ethnic variations in ischaemic stroke age of onset, subtypes, and comorbidities. South Asian populations need more research on underlying mechanisms and potential interventions for reducing the stroke burden.