Antithrombotic Medication and the Risk of Vitreous Hemorrhage in Atrial Fibrillation: Korean National Health Insurance Service National Cohort

Purpose: Antithrombotic therapy could be related with nuisance bleeding. This study investigated whether vitreous hemorrhage (VH) is associated with specific types of antithrombotic medication in patients with atrial fibrillation (AF). Materials and Methods: In the Korean National Health Insurance Service National Sample Cohort, we identified 9352 antiplatelet/anticoagulant-treated AF patients. The occurrence of VH was compared between warfarin (n=1493) and a propensity score (PS)-matched antiplatelet group (n=1493) and between warfarin (n=1493) and a PS-matched warfarin+antiplatelet group (n=1493). Results: The outcomes of VH were lower in the warfarin than in the matched antiplatelet (1.45 vs. 3.72 events/1000 patient-years) and matched warfarin+antiplatelet groups (1.45 vs. 6.87 events/1.000 patient-years). Compared with warfarin, the risk of VH increased with antiplatelet [adjusted hazard ratio (aHR) 3.90; 95% confidence interval (CI) 1.22-12.4, p=0.022] and warlarin+antiplatelet agents (aHR 4.39,95% CI 1.74-11.2, p=0.002). Compared with warfarin only, warfarin+antiplatelet agents increased the risk of VH in patients 65 years, regardless of gender and hypertension. The risk of VH was significantly higher with dual antiplatelet therapy (aHR: 5.02,95% CI: 1.56-16.2, p=0.007) or in dual (aHR: 5.02,95% CI: 1.74-14.5, p=0.003) or triple therapy using warfarin and antiplatelet agents than with warfarin monotherapy (aHR: 6.12,95%CI: 1.76-21.3, p=0.004). Conclusion: Dual antiplatelet or triple therapy increased the risk of VH significantly, compared to warfarin monotherapy. Considering the low efficacy of preventing ischemic stroke and high risk of bleeding, dual or triple therapy using warfarin and antiplatelet agents should be avoided to prevent VH in AF patients.