High Fluctuation Between Anticoagulants, Frequent Off-Label Dosing, and No Difference Concerning Outcomes: Results of a Real-Life Cohort Study

Background Recently published studies indicated a high proportion of patients taking direct oral anticoagulants (DOACs) are off-label under- or overdosed. The present study aimed at investigating whether off-label dosages are corrected over time and whether off-label doses are associated with differences in bleeding rates, ischemic stroke, or venous thromboembolism. Methods In this retrospective cohort study, patients presenting to our emergency department between January 1 and December 31, 2018, with therapeutic oral anticoagulation were included (ie, vitamin-K antagonists [VKAs], rivaroxaban, apixaban, edoxaban, and dabigatran) and follow-up for a maximum of 2 years until December 31, 2019, was made. Detailed chart reviews were performed for each case concerning characteristics, indication, bleeding complications, or changes in the used substance or dosage. Results We reviewed 2588 consultations of 1228 patients receiving therapeutic oral anticoagulation. During the maximum follow-up period of 2 years vitamin K antagonists and rivaroxaban lost the largest proportions in favor of apixaban. The overall distribution of dosage correctness remained almost unimproved (correct dosing in 62.5%, underdosing in 23.6%, coverdosing in 13.9%).The corresponding outcomes did not differ with respect to bleeding events, ischemic stroke, or venous thromboembolism among various anticoagulants as well as between correct and off-label doses. Conclusions A rising proportion of existing oral anticoagulation regimes was changed to apixaban, while the proportion of off-label dosages of all oral anticoagulants remained stable. No difference in bleeding rates, de novo strokes, or thromboembolisms was found between anticoagulants as well as between correct and off-label doses.