Adherence to a novel oral anticoagulant among patients with atrial fibrillation

BACKGROUND: Dabigatran is a direct thrombin inhibitor approved by the FDA in October 2010 for the treatment of nonvalvular atrial fibrillation. Little is known regarding patient adherence to this therapy. OBJECTIVE: To examine adherence and persistence to dabigatran among adults with atrial fibrillation. METHODS: We used IMS Health's LifeLink Health Plan Claims Database from 2010 to 2012 to identify patients with atrial fibrillation who were new users of dabigatran. We derived adherence and persistence for continuously enrolled patients at 6 months, 9 months, and 12 months of follow-up. We measured adherence using the medication possession ratio (MPR), defined as individuals with MPRs of 0.80 or greater as adherent, and examined persistence by identifying individuals with gaps in drug possession of 60 days or greater. RESULTS: Of 5,951 adults with atrial fibrillation who were new users of dabigatran, 49% had prevalent atrial fibrillation and at least 6 months of ontinuous follow-up. Of these, 89% used dabigatran as the only oral anticoagulant, whereas the remainder filled prescriptions for at least 1 other oral anticoagulant during the follow-up period. Among those using dabigatran alone (n = 2,713), the mean MPR was 0.73 (standard error = 0.30), 41% were nonadherent with therapy, and 32% had gaps of 60 days or greater. Among those observed for 9 (or 12) months who used dabigatran alone, rates of nonadherence were 47% (49%), whereas 48% (49%) discontinued therapy during follow-up. Rates of adherence and persistence were similar for patients with incident atrial fibrillation. CONCLUSIONS: Nonadherence to dabigatran was common among patients with atrial fibrillation. Future studies are needed to understand the reasons for nonadherence.