Racial differences in atrial fibrillation-related stroke: A patient-level comparative analysis of UK Biobank and Korean nationwide data

Abstract Background This study aimed to evaluate the differences in stroke risk and the impact of atrial fibrillation (AF) among racial groups by conducting a patient-level comparative analysis using two nationwide datasets. Methods and Results This study utilized data from the Korean National Health Insurance Service-Health Screening and UK Biobank, which included participants who underwent health examinations between 2005 and 2012. The primary outcome was a composite of ischemic and hemorrhagic stroke. A total of 446,986 East Asians in Korea, 3904 East Asians in the UK, and 403,240 Caucasians in the UK were analyzed. East Asians in Korea had a higher comorbidity burden compared to both UK groups ( p <0.001). During the follow-up period, the incidence of AF showed no significant difference between East Asians in Korea and the UK (Log-rank p =0.21), while Caucasians had a higher rate (Log-rank p <0.001). Incidence rates of the primary outcome per 1000 person-years were 3.78 (95% CI 3.72–3.85) for East Asians in Korea, 0.92 (95% CI 0.64–1.20) for East Asians in the UK, and 1.13 (95% CI 1.10–1.16) Caucasians in the UK. Although there was no difference between the two UK groups ( p =0.13), the rate was significantly higher among East Asians in Korea ( p <0.001). This trend consistently observed regardless of AF status or oral anticoagulant use. Conclusions Based on this patient-level analysis, East Asians in Korea, unlike East Asians in the UK, were more susceptible to stroke compared to Caucasians. This increased vulnerability was partly attributed to their higher comorbidity burden. Key messages What is new? This large-scale study utilizes patient-level data from approximately one million individuals to evaluate stroke risk differences and the impact of atrial fibrillation (AF). While East Asians in the UK demonstrated a similar stroke incidence to Caucasians in the UK, East Asians in Korea, who had the greatest burden of underlying cardiovascular disease such as hypertension, dyslipidemia, and heart failure, showed a stroke incidence rate more than three times that of the two UK race groups. The impact of AF on stroke was not significantly difference between the East Asians in Korea and Caucasians in the UK. What are the clinical implications? In contrast to East Asians in Korea, East Asians in the UK demonstrated a stroke risk similar to that of Caucasians, underscoring the imperative need for rigorous management of cardiovascular risk factors and lifestyle modification in order to prevent stroke. Future studies should investigate how other risk factors, such as extreme weather, dietary habits, and genetic factors, contribute to the differences in long-term prognosis between East Asians and other racial groups.