Racial differences in atrial fibrillation-related bleeding and mortality

Funding Acknowledgements Type of funding sources: None. Background Adverse outcomes associated with atrial fibrillation (AF) in Asians have not yet been fully elucidated. This study was designed to study racial differences in the risk for bleeding and the effect of new-onset AF on bleeding and mortality. Methods This study is based on a patient-level comparative analysis of UK Biobank and Korean National Health Insurance Service-Health Screening data. The primary outcome was intracranial hemorrhage (ICH). The secondary outcomes were major bleeding and gastrointestinal (GI) bleeding. Five-year incidence rates (IR), rate difference (IR in those with AF minus IR in those without AF) and rate ratio (IR in those with AF divided by IR in those without AF) of the outcomes were calculated. Results Between 2005 and 2012, we identified 422,121 Asians (mean [SD] age, 55.1 [8.4] years; 54.2% of men) and 380,763 Whites (mean [SD] age, 57.1 [8.0] years; 45.1% of men). During the five-year follow-up period, the IR of AF per 1000 person-years were 2.29 (95% CI, 2.22–2.35) in Asians and 3.55 (95% CI, 3.46–3.63) in Whites. The IR of ICH was greater in Asians with and without AF than in corresponding White groups. The rate difference for ICH was 1.84 (95% CI, 1.18–2.51) in Asians and 0.80 (95% CI, 0.56–1.04) in Whites. For major bleeding, the IR of Asians were not only higher than those of Whites, but also the rate difference was 1.3-fold higher in Asians than in Whites. However, different tendencies were observed for GI bleeding. Conclusion Despite the higher incidence of AF in Whites, Asians with AF have a worse prognosis in terms of ICH and major bleeding. However, further studies are needed to explain the different trends of gastrointestinal bleeding.