(P162) DEVELOPMENT AND APPLICATION OF A TAXONOMY ON THE BENEFITS OF ORAL ANTICOAGULANT SWITCHING IN ATRIAL FIBRILLATION

Background: Oral anticoagulants (OACs) are a mainstay of stroke prevention therapy in patients with atrial fibrillation (AF). AF patients often switch between the 5 OACs available; warfarin, dabigatran, rivaroxaban, apixaban, and edoxaban. Although each OAC has unique attributes (e.g. efficacy, safety, regimen complexity, and drug interactions), there are no studies examining whether the intended benefits of OAC switching are realized. The possible beneficial effects of a medication switch could be inferred by comparing the objectively known attributes of the medications involved in the switch and trial data. Administrative databases can be used to infer the consequential benefits of OAC switches, however, it requires a common language at its foundation. This study aimed to generate consensus on a taxonomy of the potential beneficial consequences of OAC switching in patients with AF and apply the taxonomy to real world data.

METHODS AND RESULTS: A Delphi study was used to solicit the input of 9 expert clinicians (7 clinical pharmacists, 2 cardiologists) through ratings, suggestions, and criticism to achieve consensus on a taxonomy. The RAND/UCLA appropriateness method (RAM) was used to analyze the data for consensus. Median ratings, disagreement index and comments made by the participants were used to iterate the taxonomy after each round. Participants were then asked to rate the applicability of the resulting taxonomy to OAC switch types that occur in practice. The resulting taxonomy was applied to OAC switch types retrospectively observed from a 10-year period of AF patients in British Columbia. The taxonomy was finalized in two rounds of Delphi with consensus on 5 items: safety, effectiveness, convenience, economic, and drug-interaction benefits (Table 1). In the 9771 OAC switches observed in the application cohort, potential safety benefits were observed: 35%, 62% and 17% of the switches had the potential to reduce the risk of major bleeding, intracranial hemorrhage and gastrointestinal bleeding respectively. Potential effectiveness benefits were also observed: 16% and 28% of the switches had the potential to reduce all-cause mortality and stroke and systemic embolism respectively. Convenience, economic and drug interaction benefits were found in 45%,12% and 46% of the OAC switches observed, respectively, while 6% of the switches had an indeterminate benefit to them.

Conclusion: It was feasible to develop a taxonomy for the benefits of OAC switching and to apply it to a real-world cohort of patients in whom switches were common. The taxonomy has potential value for future studies involving OAC and possibly other medication switches.