Direct oral anticoagulant assay utilization and associated bleeding events: a multi-center cohort study

Background: There is a lack of evidence regarding direct oral anticoagulant (DOAC) assay plasma concentrations and their association with bleeding events or transfusion requirements. This multicenter study aimed to characterize the use and plasma levels of DOAC assays of anticoagulated patients who present to emergency with a bleeding event and their association with bleeding severity.

Methods: A multicenter retrospective cohort study of consecutive emergency bleeding presentations with a DOAC assay over a five-year period was conducted. Linear regressions were performed for continuous outcomes, binary logistic regression for categorical outcomes.

Results: There were 86 patients on a DOAC, who presented with a major bleeding event, and had a DOAC assay performed. Assays were performed within a median time of 4.8 hours (IQR = 9,14.4) from presentation and had a median result of 122.9 ng/ml(IQR = 42,160). DOAC assay plasma level was not significantly associated with type or severity of bleed however, for every 10 unit increase in DOAC assay plasma level, the odds of administering reversal increases by 4% (OR = 1.04, 95%CI:1.00-1.08).

Conclusion: A wide range of plasma levels can be expected in patients who present with bleeding events. Higher DOAC plasma levels do not necessarily confer a worse bleeding event or increased transfusion requirements; however, it is associated with an increased likelihood of anticoagulant reversal administration.