Association between prothrombin time and bleeding in hospitalized patients receiving rivaroxaban

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.