Thromboembolic and bleeding complications during oral anticoagulation therapy in cancer patients with atrial fibrillation: a Danish nationwide population-based cohort study.

Coexisting cancer in patients with atrial fibrillation (AF) has been associated with thromboembolism and bleeding. We used Danish population-based medical databases to conduct a population-based cohort study that included all AF patients who redeemed a prescription for vitamin K antagonists (VKA) or non-VKA oral anticoagulant (NOAC) between July 2004 and December 2013. We characterized these patients according to the presence (N = 11,855) or absence (N = 56,264) of a cancer diagnosis before redemption of their oral anticoagulant prescription, and then examined their 1-year risk of thromboembolic or bleeding complications or death. We next used Cox regression to compare the hazard ratios for complications among VKA- or NOAC-treated AF patients with versus without a cancer diagnosis, after adjusting for sex, age, and CHA2 DS2 VASc score. One-year risks of thromboembolic complications in AF patients who redeemed a VKA prescription were similar in those with (6.5%) and without (5.8%) cancer [hazard ratio (HR) 1.0 (95% confidence interval (CI): 0.93, 1.1)]. This also was found for bleeding complications (5.4% vs. 4.3%, HR 1.1 [95% CI: 1.0, 1.2]). For AF patients with cancer who redeemed a NOAC prescription, risks were also similar for thromboembolic complications (4.9% of cancer patients vs. 5.1% of noncancer patients, HR 0.80 [95% CI: 0.61, 1.1]), and for bleeding complications (4.4% vs. 3.1%, HR 1.2 [95% CI: 0.92, 1.7]). The absolute risks of thromboembolic or bleeding complications were nearly the same in patients with and without cancer who redeemed prescription for VKAs or NOACs.