Safety and efficacy of apixaban and rivaroxaban versus warfarin in real-world atrial fibrillation patients are similar to their randomized trials: insights from GARFIELD-AF registry
Authors: Himmelreich J.C.L , Virdone S , Camm A.J , Harskamp R.E , Pieper K.S , Fox K.A.A , Bassand J.-P , Fitzmaurice D.A , Goldhaber S.Z , Goto S , Haas S , Misselwitz F , Turpie A.G.G , Verheugt F.W.A , Kakkar A.K ,   GARFIELD-AF Investigators
Published: October 2021

Abstract

Introduction
Generalisability of patient selection in the landmark trials for the approval of apixaban (ARISTOTLE) and rivaroxaban (ROCKET AF) for use in non-valvular atrial fibrillation (AF) is limited. Although observational data have confirmed the safety and efficacy of these non-vitamin K oral anticoagulants (NOACs) in unselected AF populations, robust replication of randomized trials in observational studies is warranted.

Purpose
To investigate the proportion of real-world AF patients who would have been eligible for the landmark trials for ARISTOTLE and ROCKET AF, and to assess reproducibility of these landmark trials in the largest, worldwide, prospective registry of newly diagnosed AF patients.

Methods
We analysed data from the Global Anticoagulant Registry in the FIELD–Atrial Fibrillation (GARFIELD-AF) registry. We assessed the eligibility of AF patients treated with apixaban or vitamin K antagonist (VKA) for ARISTOTLE, and those treated with rivaroxaban or VKA for ROCKET AF, using the selection criteria of the original trials. We replicated the inclusion and exclusion criteria of ARISTOTLE and ROCKET AF by deriving the set of patients eligible for each trial and calculating the adjusted hazard ratios (HRs) for stroke or systemic embolism, major bleeding, and all-cause mortality within 2 years of enrolment, using a propensity score overlap weighted Cox model. We compared the results from observational data with those reported in the original ARISTOTLE and ROCKET AF publications.

Results
Among all patients enrolled in GARFIELD-AF, 67% were eligible for recruitment in ARISTOTLE and 37% in ROCKET AF. The corresponding proportions among anticoagulated patients were 70% and 39%, respectively. Among patients on apixaban and VKA, 2570/3615 (71%) and 8005/11718 (68%), respectively, were eligible for ARISTOTLE. Of patients using rivaroxaban and VKA, 2005/4914 (41%) and 4368/11721 (37%), respectively, were eligible for ROCKET AF. Annual eligibility rates among real-world NOAC users were stable over time (Figure 1). Registry participants on rivaroxaban or VKA eligible for ROCKET AF had a higher burden of cardiovascular co-morbidity than those on apixaban or VKA eligible for ARISTOTLE. The adjusted HRs in observational data were compatible with results of the original trials in all selected outcomes (Figure 2).

Conclusion
Representativeness of ARISTOTLE and ROCKET AF for real-world AF populations was limited, with ROCKET AF's criteria being more restrictive. Despite inclusion of only incident AF cases in GARFIELD-AF versus mostly prevalent AF cases in the original trials, the results were similar. Our work indicates that the results from ARISTOTLE and ROCKET AF appear robust and reproducible in real-world patients with newly diagnosed AF.

Funding Acknowledgement
Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This work was supported by an unrestricted research grant from Bayer AG, Berlin, Germany, to TRI, London, UK, which sponsors the GARFIELD-AF registry. This work is supported by KANTOR CHARITABLE FOUNDATION for the Kantor-Kakkar Global Centre for Thrombosis Science.