Antithrombotic therapy and bleeding complications in patients with atrial fibrillation and active cancer

Abstract

Abstract Background Little is known about the extent to which an active cancer diagnosis increases bleeding and thromboembolic risks in atrial fibrillation (AF) patients. Data on major bleeding rates per antithrombotic management strategy are lacking in AF patients with active cancer. Purpose To examine the incidence rates of major bleeding per antithrombotic treatment in AF patients with active cancer and to examine whether cancer type impacts major bleeding and thromboembolic risks. Methods We used Danish population-based health care databases to conduct this cohort study. We included all incident AF (including atrial flutter) patients aged ≥50 years between January 1st 1995 and December 31st 2016, out of whom we identified AF patients who subsequently developed cancer. We used International Classification of Diseases 10th Revision codes to identify data on cancer type and outcomes (i.e. major bleeding, arterial and venous thromboembolism). We used Anatomical Therapeutic Chemical codes to provide information on antithrombotic treatment (e.g. no anticoagulant treatment, platelet inhibitors, vitamin K antagonists, direct oral anticoagulants, or a combination of antithrombotic drugs) which was evaluated as a time-dependent variable. The follow-up started from the incident cancer diagnosis until the occurrence of an outcome, death or the end of the two year follow-up. Incidence rates per 100 patient-years and adjusted hazard ratios were computed. Results 22,996 AF patients with a subsequent incident cancer diagnosis were included in the study. These patients had higher major bleeding and thromboembolic risk compared to those without cancer, with adjusted HRs of 2.11 (1.99–2.23) and 1.36 (1.27–1.44), respectively (Figure 1). Highest bleeding risk was observed for intracranial and respiratory cancer, while haematological and respiratory cancer were associated with highest thromboembolic risk. Bleeding risk increased with increasing number of antithrombotic drugs and was higher in AF patients with active cancer compared to those without, across all exposure categories (Figure 2). Conclusions Patients with AF and active cancer are at increased risk of major bleeding and thromboembolisms than those without cancer. Treatment with dual or triple antithrombotic therapy in AF patients with active cancer showed very high bleeding rates. Funding Acknowledgement Type of funding sources: None.