Abstract 14106: High Cardiovascular Risk and Frequent Cardiovascular Medication Use Among Oral Anticoagulant-Naive Initiators of Rivaroxaban and Vitamin K Antagonists.

Introduction: Vitamin K antagonists (VKA) are the standard of care for stroke prevention in non-valvular atrial fibrillation (SPAF), venous thromboembolism treatment (VTE-T) and VTE prevention after knee/hip replacement surgery. Rivaroxaban, a direct factor Xa inhibitor, is also approved for these indications. As many patients requiring anticoagulants have cardiovascular comorbidities, medication use at anticoagulant initiation is of interest. Methods: Data from the Health Improvement Network (UK), the PHARMO Database Network (Netherlands), the German Pharmacoepidemiological Research Database and the Swedish National public Health Registers were used in a post-authorization study program to characterize anticoagulant-naive rivaroxaban and VKA users aged ≥2 years and to assess drug utilization patterns. Results: Overall, 136,927 rivaroxaban and 248,694 VKA new users were anticoagulant-naïve. Across the databases, median age ranged from 69-72 years for rivaroxaban and 72-73 years for VKA users; 46-56% and 53-56%, respectively, were male. The most common indication for rivaroxaban use in all countries was SPAF (31-53%). Overall, SPAF patients had high cardiovascular risk (mean modified CHA2DS2VASc score: 2.9-3.9 for rivaroxaban, 3.2-4.0 for VKA). The most frequent comorbidities were hypertension, coronary artery disease and vascular disease. Beta blockers, aspirin and statins were the most common drugs used in the pre-index year (Table), likely reflecting patients' high cardiovascular risk profile. For VTE-T, higher use of low-molecular-weight heparin in VKA (24-70%) than rivaroxaban (15-22%) users may reflect use of heparin as a bridging therapy due to VKA's slow onset of action; this is not needed for rivaroxaban. Conclusions: Patients starting anticoagulation are often on several medications; this may reflect their high cardiovascular risk profile and the need for bridging therapies with heparin in VKA users following surgery. [ABSTRACT FROM AUTHOR]