Clinical Summary

Appropriateness of initial dose of NOACs in non-valvular Afib

Sarfaroj Khan

Takeaway

Majority of patients with non-valvular atrial fibrillation (Afib) starting therapy with non-vitamin K antagonist oral anticoagulants (NOACs: apixaban, dabigatran, and rivaroxaban) were prescribed appropriate daily dose based on the approved European Union (EU) drug label in the UK.
However, underdosing was twice as frequent among patients starting treatment on apixaban than those on dabigatran or rivaroxaban.

Why this matters

This is the first and largest assessment for appropriateness of the initial prescribed daily dose of NOACs to patients with non-valvular Afib in the UK.
Findings warrant research into the patient characteristics that may influence inappropriate underdosing of NOACs.

Study design

Population-based study included 30,467 patients (age, ≥18 years) with non-valvular Afib with a first prescription for NOAC from the UK primary care (January 2011-December 2016).
Outcome: percentage of patients prescribed a NOAC dose according to the European Union (EU) labels (appropriately dosed), and not according to the EU labels (inappropriately dosed).
Funding: BAG.

Key results

50.1% of patients started on rivaroxaban, 35.6% on apixaban and 14.4% on dabigatran.
According to the EU labels, percentage of patients prescribed daily dose of first apixaban, dabigatran and rivaroxaban included:
- recommended dose: 74.9%, 74.4% and 84.2%;
- lower than recommended: 21.6%, 8.7% and 9.1% and
- higher than recommended: 3.5%, 16.9% and 6.6%, respectively.
Patients with severe renal impairment received reduced dose of apixaban (≤5 mg, 91.1%), dabigatran (≤200 mg, 80.0%) and rivaroxaban (15 mg, 83.0%).