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Atrial fibrillation in patients with a history of cancer and risk of bleeding complications associated with antithrombotic therapy


 
 
 Up to one in four patients with atrial fibrillation (AF) has a cancer diagnosis. It is largely unknown to which extent a prior cancer diagnosis affects major bleeding and thromboembolic risk in AF patients. Moreover, data on major bleeding rates per antithrombotic treatment type are lacking in these patients.
 
 
 
 To examine the incidence rates of major bleeding per antithrombotic treatment in AF patients with prior cancer and to examine whether cancer type and the time-interval between AF and cancer influence major bleeding and thromboembolic risks.
 
 
 
 This nationwide population-based cohort study included incident Danish AF patients aged ≥50 years between 01–01–1995 and 31–12–2016. Data on prior cancer, major bleeding and thromboembolisms (i.e. arterial and venous) were obtained from Danish health registries via International Classification of Diseases 10th Revision codes. We stratified according to prior cancer and by time between the AF and cancer diagnosis (i.e. <1 year, 1–3 years, >3 years), and cancer type. Data on antithrombotic exposure (e.g. no anticoagulant treatment, platelet inhibitors, vitamin K antagonists, direct oral anticoagulants, or combination of antithrombotic drugs) were evaluated as a time-dependent variable. We computed incidence rates per 100 patient-years and adjusted hazard ratios in a Cox regression model.
 
 
 
 We identified 39,178 AF patients with a prior cancer diagnosis. Bleeding risk increased with increasing number of antithrombotic drugs and was higher in AF patients with a history of cancer compared to those without, across all exposure categories (Figure 1). The increased bleeding risk was similar across different time intervals between cancer and AF diagnosis. The increased thromboembolic risk steeply declined with increasing time intervals between AF and cancer diagnosis (Figure 2). Prior gastrointestinal, intracranial, haematological, respiratory and urogenital cancers were associated with an increased bleeding risk. The two latter cancer types were also associated with increased thromboembolic risks.
 
 
 
 We showed that patients with atrial fibrillation and a prior history of cancer experience higher rates of bleeding than those without cancer. Both respiratory and urogenital cancers had the highest rates of bleeding and thromboembolisms.
 
 
 
 Type of funding sources: None.
