Does Ethnicity Alters the Risk of Stroke in Patients with Modifiable Cardiometabolic Risk Factors?

Background Ethnic inequality in stroke risk was partially explained by history of hypertension, diabetes, and socioeconomic status. We aimed to estimate the impact of ethnicity on stroke risk in patients with hypertension, diabetes or hypercholesterolaemia. Methods Multistate models were constructed using electronic health records including date at onset of stroke, stroke risk factors, and the Index of Multiple Deprivation in adult patients of Asian, Black, or White ethnicity, registered in 41 general practices in south London between 2005 and 2021. Transitions to hypertension, diabetes, or hypercholesterolaemia (transition 1) and from these risk factors to stroke (transitions 2) were considered. Results Of the 849,968 registered patients, 651,888 (76·7%) were of Asian (8·6%), Black (18·2%), or White (73·2%) ethnicity and 54·1% were female. Patients of Black ethnicity had higher incidence of stroke (2·1%) and cardiometabolic risk factors, whereas patients of Asian and White ethnicity had intermediate and lower levels of stroke (1·2% and 1·0% respectively) and cardiometabolic risk factors. Asian and Black ethnicities were associated with higher risks in transition 1 compared to White ethnicity. Ethnicity did not alter transition 2, except for hypercholesterolaemia, Black ethnicity being associated with higher risk of stroke compared to Asian and White ethnicity. Conclusion Our results confirm that Black ethnicity does not confer excess stroke risk in patients with hypertension or diabetes. This observation was also made for Asian ethnicity. Black ethnicity was associated with increased stroke risk only in patients with Hypercholesterolaemia. Funding Guys and St Thomas grant (EIC180702).