Should oral anticoagulants still be prescribed to patients with atrial fibrillation with a single stroke risk factor but at high bleeding risk- A nationwide cohort study

Aims: To investigate the co-distributions of stroke and bleeding risks in Asian patients with atrial fibrillation (AF) and the clinical benefits of oral anticoagulants (OACs) among AF patients with a single stroke risk factor but at high bleeding risk. Methods and results: From 1 January 2001 to 31 December 2016, a total of 404 949 AF patients were retrospectively identified from Taiwan National Health Insurance Research Database. Stroke risk was assessed using the CHA2DS2-VASc score and was categorized into low risk (score = 0 for males and 1 for females), intermediate risk (i.e. a single non-sex stroke risk factor; score = 1 for males and 2 for females), and high risk (score ≥2 for males and ≥3 for females). A high risk of bleeding was defined as a HAS-BLED score ≥3. Around 57.5% of AF patients were at high risk for both stroke and bleeding, and most patients (97.6%) with a low stroke risk were also at low risk for bleeding. Around 18.3% of patients with a CHA2DS2-VASc score of 1 (males) or 2 (females) were at high bleeding risk, and the use of OACs in such patients was associated with a lower risk of composite adverse events of ischaemic stroke, intracranial haemorrhage, or mortality (4.19/100 person-years vs. 5.22/100 person-years, adjusted hazard ratio = 0.781, P = 0.04). Conclusion: For AF patients with an intermediate risk of stroke (i.e. a single non-sex stroke risk factor) but at high bleeding risk, the use of OACs was still significantly associated with a better overall clinical outcome.