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

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. Keywords: East Asians, atrial fibrillation, stroke ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research was supported by a grant of Patient-Centered Clinical Research Coordinating Center (PACEN) funded by the Ministry of Health & Welfare, Republic of Korea (HC19C0130) ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by the institutional review board of Yonsei University Health System (4-2022-1241). Regarding the K-NHIS-HealS, the informed consent requirement was waived because personal identification information was removed after cohort generation. The UK Biobank study has approval from the North West Multicenter Research Ethics Committee (REC approval 21/NM/0157). This research was conducted using the UK Biobank resource under application 77793. Informed consent was obtained by UK Biobank for all participants. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data and materials of the K-NHIS-HealS and UK Biobank are accessible to the public on their respective homepages (K-NHIS-HealS, http://nhiss.nhis.or.kr; UK Biobank, http://www.ukbiobank.ac.uk). Authorized researchers received anonymous raw data when the independent access subcommittee approved them following the evaluation of all requests for data use by the executive team.