Dabigatran adherence in atrial fibrillation patients during the first year after diagnosis: a nationwide cohort study

BACKGROUND: There is a perception among physicians that lack of routine monitoring with non-vitamin K antagonist oral anticoagulants (NOACs) may lead to poor medication adherence. We studied adherence during the first year of usage in a cohort of patients with newly diagnosed non-valvular atrial fibrillation (AF) started on the NOAC, dabigatran etexilate.

METHODS AND RESULTS: Nationwide Danish patient and prescription purchase registries were used to identify newly diagnosed AF patients initiating dabigatran, co-morbidities, and refill patterns under a twice-daily, one pill regimen. Adherence was characterised among remaining users (N=2,960) after 1 year using the proportion of days covered (PDC), gap rates, and restart rates. The overall 1-year PDC was 83.9%, with 76.8% patients having a 1-year PDC in excess of 80%. Patients with CHA2 DS2 -VASc score ≥2 were more adherent than patients with CHA2 DS2 -VASc score of 1 (PDC ratio: 1.12; 95% confidence interval [CI]: 1.08-1.17) and generally patients with higher morbidity were more adherent. In particular, patients with prior bleeding were more adherent than patients with no prior bleeding (PDC ratio: 1.02; 95% CI: 0.98-1.06). The overall gap rate was 1.4 gaps per year. There were no clear tendencies in gap rates among subgroups, although patients with higher morbidity tended to have slightly more, but shorter gap periods.

CONCLUSION: More than 75% of patients were adherent >80% during the first year. Patients with higher morbidity, including patients with a higher risk of stroke or bleeding, exhibited better adherence. This improvement may be attributable to more regular contact with the health care system. This article is protected by copyright. All rights reserved.