Site-Level Variation in and Practices Associated With Dabigatran Adherence

IMPORTANCE Unlike warfarin, which requires routine laboratory testing and dose adjustment, target-specific oral anticoagulants like dabigatran do not. However, optimal follow-up infrastructure and modifiable site-level factors associated with improved adherence to dabigatran are unknown. OBJECTIVES To assess site-level variation in dabigatran adherence and to identify site-level practices associated with higher dabigatran adherence. DESIGN, SETTING, AND PARTICIPANTS Mixed-methods study involving retrospective quantitative and cross-sectional qualitative data. A total of 67 Veterans Health Administration sites with 20 or more patients filling dabigatran prescriptions between 2010 and 2012 for nonvalvular atrial fibrillation were sampled (4863 total patients; median, 51 patients per site). Forty-seven pharmacists from 41 eligible sites participated in the qualitative inquiry. EXPOSURE Site-level practices identified included appropriate patient selection, pharmacist-driven patient education, and pharmacist-led adverse event and adherence monitoring. MAIN OUTCOMES AND MEASURES Dabigatran adherence (intensity of drug use during therapy) defined by proportion of days covered (ratio of days supplied by prescription to follow-up duration) of 80% or more. RESULTS The median proportion of patients adherent to dabigatran was 74% (interquartile range [IQR], 66%-80%). After multivariable adjustment, dabigatran adherence across sites varied by a median odds ratio of 1.57. Review of practices across participating sites showed that appropriate patient selection was performed at 31 sites, pharmacist-led education was provided at 30 sites, and pharmacist-led monitoring at 28 sites. The proportion of adherent patients was higher at sites performing appropriate selection (75% vs 69%), education (76% vs 66%), and monitoring (77% vs 65%). Following multivariable adjustment, association between pharmacist-led education and dabigatran adherence was not statistically significant (relative risk [RR], 0.94; 95% Cl, 0.83-1.06). Appropriate patient selection (RR, 1.14; 95% Cl, 1.05-1.25), and provision of pharmacist-led monitoring (RR, 1.25; 95% Cl, 1.11-1.40 were associated with better patient adherence. Additionally, longer duration of monitoring and providing more intensive care to nonadherent patients in collaboration with the clinician improved adherence. CONCLUSIONS AND RELEVANCE Among nonvalvular atrial fibrillation patients treated with dabigatran, there was variability in patient medication adherence across Veterans Health Administration sites. Specific pharmacist-based activities were associated with greater patient adherence to dabigatran.