Appropriateness of Dabigatran and Rivaroxaban Prescribing for Hospital Inpatients

Background: Recent approval of the new oral anticoagulants dabigatran and rivaroxaban has led to rapid changes in anticoagulant prescribing practices. Postmarketing reports have highlighted safety concerns with these agents, and their use outside of evidence-based recommendations was noted at the authors' centre. Objectives: To determine the incidence of and risk factors associated with inappropriate prescribing of dabigatran and rivaroxaban. Methods: This retrospective cohort study investigated randomly selected dabigatran or rivaroxaban prescriptions for patients admitted to a tertiary teaching hospital between January 2010 and December 2012. Appropriateness of prescribing was determined from the documented indication, drug dosage, patient's renal function, and presence of drug interactions, if applicable. Results: Among a total of 321 medication orders reviewed, the incidence of inappropriate use was 31.2% (34/109) for dabigatran and 26.9% (57/212) for rivaroxaban. Of the 97 reasons for inappropriate use that were identified, the most common were prescribing for an unapproved indication (49/97 [50.5%]), concomitant prescribing of another anti coagulant (22/97 [22.7%]), and high prescribed dose (9/97 [9.3%]). The prescribing service was found to be an independent risk factor for inappropriate prescribing (p = 0.041). Corrections were made to 23.1% (21/91) of the incorrect regimens before hospital discharge. In a sensitivity analysis using calculated ideal body weight to estimate renal function, the overall incidence of inappropriate prescribing increased to 31.5% (101/321). Conclusions: The proportion of patients with inappropriate prescribing of dabigatran or rivaroxaban in clinical practice was higher than expected. Educational interventions and pharmacy-led initiatives with a focus on appropriate indications, concomitant anticoagulant prescribing, and review of dosage regimens are recommended to improve patient safety.