Secondary adherence to non-vitamin-K antagonist oral anticoagulants in patients with atrial fibrillation in Sweden and the Netherlands

Abstract

Objective: There is limited evidence on patients’ adherence and the impact of the prescribed dosing regimen in non-vitamin-K oral anticoagulants (NOACs). We aimed to assess secondary adherence to NOACs and to determine the impact of the dosing regimen in patients with atrial fibrillation.

Methods: Patients using a NOAC between 2009 and 2013 were identified from the nation-wide Swedish Prescribed Drug Register and the Dutch regional IADB.nl database. Patients using a consistent dosage for at least 180 consecutive days were included. Adherence was calculated using the medication possession ratio (MPR) and adjusted for overlapping dates. Adherence was defined as a MPR ≥0.8. Sensitivity analyses were performed using a MPR ≥0.9. Logistic regression was performed to compare secondary adherence and to explore the influence of the dosing regimen.

Results: A total of 5254 Swedish and 430 Dutch NOAC users were included. The mean MPR was 96.0% (SD 7.8%) in Sweden and 95.1% (SD 10.1%) in the Netherlands. Multivariable logistic regression analysis showed that a twice daily regimen had a lower likelihood of being secondary adherent compared to a once daily regimen in Sweden (odds ratio [OR] 0.21 [95% CI 0.12–0.35]).

Limitations: The influence of selection bias introduced by the inclusion criterion of ≥2 dispensations covering at least 180 days could not be excluded.

Conclusions: This study demonstrated that secondary adherence was high in this specific setting among patients with at least two initial dispensations of a NOAC covering a minimum of 180 days. The use of NOACs in a once daily regimen showed higher adherence compared to a twice daily regimen.

Keywords:

• Adherence
• non-vitamin-K oral anticoagulants
• anticoagulation
• dosing regimen
• apixaban
• dabigatran
• rivaroxaban

Transparency

Declaration of funding

This article was not funded.

Author contributions: J.F.S. and M.J.P. were involved in the conception and design. J.F.S., M.H., L.A.L. and M.J.P. were involved in the analysis, interpretation of the data, drafting the paper and critical revision. M.S.J. was involved in the interpretation of the data, drafting of the paper and critical revision. P.T.d.B. was involved in the critical revision of the paper.

Declaration of financial and other relationships

M.J.P. has disclosed that he has received grants and honoraria from various pharmaceutical companies, including those developing, producing and marketing NOACs; none of this financial support was related to the work presented here. L.A.L has disclosed that he has received a grant from Boehringer Ingelheim, was an advisor and received lecture fees from Bayer, Boehringer Ingelheim and Pfizer/BMS; none of these relationships were related to the work presented here. M.S.J., J.F.S., P.T.d.B. and M.H. have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article.

A CMRO peer reviewer on this manuscript declares consultancy fees from Boehringer Ingelheim. The other peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgements

The authors would like to thank J.F.M. van Boven and J. Stevanovic for their assistance with writing the initial manuscript.