Bleeding complications in patients with gastrointestinal cancer and atrial fibrillation treated with oral anticoagulants

Background: Direct oral anticoagulants (DOACs) may increase the risk of gastrointestinal (GI) bleeding in patients with atrial fibrillation (AF) and GI cancer compared with vitamin K antagonists (VKA). Methods: We conducted a Danish nationwide cohort study comparing the bleeding risk associated with DOAC versus VKA in patients with AF and GI cancer. We calculated crude bleeding rates per 100 person-years (PYs) for GI and major bleeding. We then compared rates of bleeding at 1 year after initial oral anticoagulation filled prescription by treatment regimen using inverse probability of treatment weighting and Cox regression. Results: The unweighted study population included 1476 AF patients with GI cancer (41.6% women, median age 78 years) initiating a DOAC and 652 initiating a VKA. One-year risk of GI bleeding was 5.0% in the DOAC group and 4.7% in the VKA group with a corresponding weighted hazard ratio (HR) of 0.95 (95% confidence interval [CI]: 0.63, 1.45). For patients with active cancer, weighted GI bleeding rates were slightly higher in both the VKA and DOAC group, and the weighted HR was 1.00 (95% CI: 0.53, 1.88). The HR was 1.12 (95% CI: 0.71, 1.76) for all bleedings. Hazard ratios for GI bleeding were 0.61 (95% CI: 0.25, 1.52) for patients with upper GI cancer, and 0.92 (95% CI: 0.58, 1.46) in patients with colorectal cancer. Conclusion: Evidence from this nationwide cohort study suggests a comparable 1-year risk of bleeding associated with DOAC compared with VKA among patients with AF and GI cancer.