Also in a real-world setting, novel oral anticoagulants were associated with better outcomes

Coleman C, Antz M, Bowrin K, et al.
Curr Med Res Opin. 2016 Sep 20:1-7. [Epub ahead of print]

Background

Randomised clinical trials have demonstrated favourable efficacy and safety profiles for the oral factor Xa inhibitors rivaroxaban, apixaban, edoxaban, compared to warfarin [1-3]. However, in clinical practice oral anticoagulants (OACs) may be used differently.

In the ‘Real-world evidence on stroke prevention in patients with atrial fibrillation in the United States’ (REVISIT-US) study, the efficacy and safety of rivaroxaban or apixaban was compared to warfarin in NVAF patients in a real-life setting using data from a large, US administrative claims database. Patients were OAC treatment naïve in the 180-days prior to the treatment and had never been treated to rivaroxaban or apixaban. Each eligible rivaroxaban user or apixaban user was 1:1 propensity-score matched to a warfarin user. Primary endpoints were ischemic stroke and intracranial hemorrhage (ICH).

Main results

• 11.411 rivaroxaban users were matched to 11.411 warfarin users.
• A lower hazard of ischemic stroke or ICH was noticed for rivaroxaban users compared to warfarin users (HR: 0.61, 95% CI: 0.45-0.82).
• Separately, both HRs for stroke and ICH were lower for rivaroxaban compared to warfarin (HR: 0.71, 95% CI: 0.47-1.07 and HR:0.53, 95% CI: 0.35-0.79 respectively).

• 4.083 apixaban users were matched to 4.083 warfarin users.
• A lower hazard of ischemic stroke or ICH was noticed for apixaban users compared to warfarin users (HR: 0.63, 95% CI: 0.35-1.12), although non-significant.
• Separately, the HR for ICH was 0.38 (95% CI: 0.17-0.88), whereas this increased for ischemic stroke (HR: 1.13, 95% CI: 0.49-2.63, non-statistically).

Conclusion

The real-world REVISIT-US study of NVAF patients within the United States confirmed results of the corresponding phase III trials (ROCKET-AF, ARISTOTLE); both rivaroxaban and apixaban were associated with less intracranial haemorrhage versus warfarin. Further investigations need to be done regarding the non-statistically significant higher rate of ischemic stroke with apixaban compared to warfarin, as this was observed in a relatively small number of patients. One explanation might be the more frequently use of the reduced apixaban dose (2.5mg twice daily) or poor adherence.

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References

1. Patel MR, Mahaffey KW, Garg J, et al.; ROCKET AF Investigators. Rivaroxaban versus warfarin in nonvalvular atrial fibrillation. N Engl J Med. 2011;365:883-891.
2. Granger CB, Alexander JH, McMurray JJ, et al., ARISTOTLE Committees and Investigators. Apixaban versus warfarin in patients with atrial fibrillation. N Engl J Med. 2011;365:981-92.
3. Giugliano RP, Ruff CT, Braunwald E, Murphy SA et al., ENGAGE AF-TIMI 48 Investigators. Edoxaban versus warfarin in patients with atrial fibrillation. N Engl J Med. 2013;369:2093-104.