Purpose: Direct oral anticoagulants (DOACs) have been promoted in patients with nonvalvular atrial fibrillation (nv-AF) as a more convenient alternative to vitamin K antagonists. We estimated 1-year dabigatran and rivaroxaban adherence rates in nv-AF patients and assessed associations between baseline patient characteristics and nonadherence.
Methods: This cohort study included OAC-naive nv-AF patients with no contraindications to OAC, who initiated dabigatran and rivaroxaban, using nationwide data from French national health care databases. One-year adherence was defined by the proportion of days covered of 80% or more over a fixed 1-year period after treatment initiation. Associations between nonadherence and baseline patient characteristics were assessed using multivariate logistic regression models.
Results: The population was composed of 11 141 dabigatran (women: 48%; mean age: 74 ± 10.7 y; ≥80 y: 34.9%) and 11 126 rivaroxaban (46.5%; 74 ± 10.9 y; 34.8%) new users. One-year adherence was 53.3% in dabigatran-treated and 59.9% in rivaroxaban-treated patients, consistent with numerous subgroup analyses. A switch to vitamin K antagonist was observed in 14.5% of dabigatran and 11.7% of rivaroxaban patients; 10.2% and 5.9% of patients switched to another DOAC, respectively; and 4.3% of patients died in the 2 cohorts. In patients who did not die or switch during the follow-up, 1-year adherence was 69.6% in dabigatran-treated and 72.3% in rivaroxaban-treated patients. Having concomitant ischemic heart diseases was associated with an increased risk of nonadherence in the 2 cohorts.
Conclusion: In this real-life study, 1-year adherence to DOAC is poor in nv-AF new users. Despite the introduction of DOAC, adherence to OACs may remain a significant challenge in AF patients.
Keywords: French health care databases; adherence; atrial fibrillation; direct oral anticoagulants; pharmacoepidemiology.
© 2017 The Authors. Pharmacoepidemiology & Drug Safety published by John Wiley & Sons Ltd.