Electronic monitoring of adherence to once-daily and twice-daily direct oral anticoagulants in patients with atrial fibrillation: Baseline data from the SMAAP-AF trial

Background: Nonadherence diminishes the efficacy of direct oral anticoagulants (DOACs) in patients with nonvalvular atrial fibrillation (NVAF). This report presents the baseline survey results regarding medication adherence among NVAF patients who were treated with once-daily edoxaban or twice-daily apixaban from a randomized control trial of the effect of an educational intervention on DOAC adherence. Methods: We prospectively studied 301 NVAF patients who were treated with edoxaban (n = 175) or apixaban (n = 126) during the 12-week observation period. Adherence was measured with an electronic monitoring system and is expressed as the percentage of days with the correct doses in the measurement period (days). Adherence to DOAC therapy was defined based on the standard threshold (>= 80%) or a strict threshold (>= 90%). Results: Of the 301 patients, 33 had incomplete data or protocol deviations, leaving 268 patients (edoxaban 158 and apixaban 110) for the per-protocol baseline analysis. There was no difference in adherence (threshold >= 80%) between the groups (edoxaban 95% vs apixaban 91%, P = .2), but there was a lower proportion of patients with strict adherence (threshold >= 90%) among apixaban users than among edoxaban users (edoxaban 87% vs apixaban 76%, P = .02). Multivariate analysis showed a negative relationship between apixaban use and an adherence rate >= 9.0% (odds ratio 0.49, 95% confidence interval [CI]: 0.25-0.94). Conclusions: Our study showed that the proportion of DOAC users with adherence (>= 80%) did not differ between the groups, but the proportion of patients with strict adherence (>= 90%) was lower among those using apixaban than among those using edoxaban.