Oral anticoagulation in emergency department patients: high rates of off-label doses,no difference in bleeding rates

Abstract Background Empirically, a significant proportion of patients using Direct Oral AntiCoagulation (DOAC) take off-label reduced doses. We aimed to investigate: the prevalence, indications, doages and bleeding complications of oral anticoagulants on admission to the emergency department Methods In this retrospective analysis patients presenting to our emergency department between January 1st and December 31st 2018 with therapeutic oral anticoagulation were included (vitamin-K antagonists, rivaroxaban, apixaban, edoxaban, dabigatran). A detailed chart review was performed for each case concerning characteristics, indication and bleeding complications. Results 19.662 consecutive emergency department cases were reported. 1.721 (9%) had therapeutic oral anticoagulation. Vitamin-K antagonists (41%), rivaroxaban (36%) and apixaban (19%) were the most common. Stroke prophylaxis in patients with atrial fibrillation (63.2%) and venous thromboembolism (24.1%) were the most common indications. In 27 cases (1.6%) no indication could be identified. 32% of patients were classified to have either off label-doses of DOACs or an INR out of range (in vitamin-K antagonists), while 20% were classified as off-label under-dosed and 12% as over-dosed. No difference in likelihood of bleeding on admission could be found between the respective drugs. Only concomitant use of aspirin was significantly associated with presence and higher severity of bleeding. Conclusions Vitamin-K antagonists are still the most widely used drug followed by rivaroxaban. A significant proportion of patients are being prescribed off label-doses. While no difference was found for the respective anticoagulants with respect to bleeding, concomitant aspirin use was a significant predictor for bleeding in our collective.