Testing the therapeutic equivalence of novel oral anticoagulants for thromboprophylaxis in orthopedic surgery and for prevention of stroke in atrial fibrillation

Background: In studying the comparative effectiveness of novel oral anticoagulants (NOACs) in orthopedic surgery and in non-valvular atrial fibrillation, previous meta-analyses have found no proof of difference in head-to-head indirect comparisons between individual agents. However, the question of their therapeutic equivalence remains unanswered. Objectives: The objective of this analysis was to test the equivalence of three NOACs (dabigatran, rivaroxaban, apixaban) in orthopedic surgery and four NOACs (dabigatran, rivaroxaban, apixaban, and edoxaban) in non-valvular atrial fibrillation. Methods: Standard pair-wise meta-analysis and network meta-analysis for indirect comparisons were combined with equivalence testing. The endpoint was venous thromboembolism in orthopedic surgery and a composite of stroke or systemic embolism in atrial fibrillation. Comparisons were expressed as risk difference (RD). Margins for equivalence testing were derived from the original trials. Results: Our results indicate that rivaroxaban and apixaban (but not dabigatran) are equivalent for thromboprophylaxis in orthopedic surgery. In atrial fibrillation, all the four NOACs we tested were found to meet the criterion of therapeutic equivalence. Some concern, however, is raised by some findings focused on adverse events of these agents, in which the equivalence was not proven in all analyses. Conclusions: Regardless of clinical implications, our results can be the basis to develop local acquisition tenderings on NOACS. In Italy, a new law has been issued according to which equivalence analyses have become a mandatory prerequisite for local tenderings.