CHA₂DS₂-VASc score and risk of thromboembolism and bleeding in patients with atrial fibrillation and recent cancer

Background: Cancer may influence the risk of thromboembolism and bleeding associated with the CHA ₂DS ₂-VASc score. We examined the risk of thromboembolism and bleeding associated with the CHA ₂DS ₂-VASc score in atrial fibrillation patients with and without recent cancer. Methods and results: Using nationwide registers all patients diagnosed with atrial fibrillation from 2000 to 2015 and not on oral anticoagulation or heparin therapy were included and followed for 2 years. Recent cancer was defined by a cancer diagnosis 5 years or fewer earlier. Risks of thromboembolism and bleeding were estimated in cumulative incidence curves and Cox regression models.We included 122,053 patients with incident atrial fibrillation, 12,014 (10%) had recent cancer. The 2-year cumulative incidence of thromboembolism and bleeding in patients with versus without recent cancer was 1.7% (95% confidence interval (CI) 0.5–2.8) and 4.3% (95% CI 2.4–6.2) versus 1.2% (95% CI 0.9–1.5) and 1.7% (95% CI 1.4–2.0) for CHA ₂DS ₂-VASc score 0; 3.2% (95%CI 2.2-4.3) and 4.4% (95%CI 3.2-5.6) versus 1.8% (95%CI 1.6-2.1) and 3.0% (95% CI 2.7–3.3) for CHA2DS2-VASc score 1; and 7.1% (95% CI 6.6–7.7) and 6.8% (95% CI 6.3–7.2) versus 10.9% (95% CI 10.7– 11.1) and 6.2% (95% CI 6.1–6.4) for CHA2DS2-VASc score 2 or greater. Although the CHA ₂DS ₂-VASc score was associated with thromboembolism and bleeding in both patients with and without cancer, the association differed between the groups for thromboembolism (test for interaction, p<0.001) and bleeding (test for interaction, p<0.001). Conclusion: The association of the CHA ₂DS ₂-VASc score and risk of thromboembolism and bleeding differed between atrial fibrillation patients with and without recent cancer. Therefore, the CHA ₂DS ₂-VASc score should be used with caution in patients with recent cancer.