Purpose: Results of an investigation of the pharmacodynamic effect of rivaroxaban anticoagulation, as measured by prothrombin time (PT), on bleeding risk and other outcomes in hospitalized patients are reported.
Methods: In a single-center retrospective cohort study, adult inpatients who had a PT measured within 24 hours after rivaroxaban administration during a designated 23-month period were identified. Patients who experienced in-hospital bleeding events were compared with those who did not. A multivariable logistic regression model was used to quantify the association between PT and bleeding events while adjusting for albumin levels and use of nonsteroidal antiinflammatory drugs and/or antiplatelet agents. Thromboembolic events were assessed as a secondary outcome.
Results: A total of 199 patients met the criteria for inclusion in the analysis; 41 experienced a bleeding event. Among patients with a PT of ≥30 seconds versus a PT of <30 seconds, the overall rate of bleeding events was significantly higher (38.7% versus 17.3%, p = 0.0067). Results of multivariable regression modeling showed that a PT of ≥30 seconds correlated with an approximately 3-fold higher bleeding risk (odds ratio, 3.25; 95% confidence interval, 1.09-9.66). Hypoalbuminemia was also a positive predictor of bleeding risk. There was no significant between-group difference in thromboembolic events.
Conclusion: In hospitalized patients receiving rivaroxaban who had coagulation tests performed, a PT of ≥30 seconds was associated with a higher risk of bleeding. Hypoalbuminemia was also associated with bleeding in this population.
Keywords: DOAC monitoring; bleeding; direct oral anticoagulant; prothrombin time; rivaroxaban; thromboembolic.
Copyright © 2018 by the American Society of Health-System Pharmacists, Inc. All rights reserved.