Arterial Thromboembolism in Patients With AF and CHA₂DS₂-VASc Score 0-2 With and Without Cancer

Background: It is unclear whether newly diagnosed cancer adds to the risk of arterial thromboembolism (ATE) in patients with atrial fibrillation/flutter (AF). This is especially relevant for AF patients with low to intermediate CHA₂DS₂-VASc scores in whom the risk-benefit ratios between ATE and bleeding are delicately balanced. Objectives: The objectives were to evaluate the ATE risk in AF patients with a CHA₂DS₂-VASc score of 0 to 2 with and without cancer. Methods: A population-based retrospective cohort study was performed. Patients with a CHA₂DS₂-VASc score of 0 to 2 not receiving anticoagulation at cancer diagnosis (or the matched index date) were included. Patients with embolic ATE or cancer before study index were excluded. AF patients were categorized into AF and cancer and AF and no cancer cohorts. Cohorts were matched for multinomial distribution of age, sex, index year, AF duration, CHA₂DS₂-VASc score, and low/high/undefined ATE risk cancer. Patients were followed from study index until the primary outcome or death. The primary outcome was acute ATE (ischemic stroke, transient ischemic attack, or systemic ATE) at 12 months using International Classification of Diseases-Ninth Revision codes from hospitalization. The Fine-Gray competing risk model was used to estimate the HR for ATE with death as a competing risk. Results: The 12-month cumulative incidence of ATE was 2.13% (95% CI: 1.47-2.99) in 1,411 AF patients with cancer and 0.8% (95% CI: 0.56-1.10) in 4,233 AF patients without cancer (HR: 2.70; 95% CI: 1.65-4.41). The risk was highest in men with CHA₂DS₂-VASc = 1 and women with CHA₂DS₂-VASc = 2 (HR: 6.07; 95% CI: 2.45-15.01). Conclusions: In AF patients with CHA₂DS₂-VASc scores of 0 to 2, newly diagnosed cancer is associated with an increased incidence of stroke, transient ischemic attack, or systemic ATE compared with matched controls without cancer.