OBJECTIVES: There is limited data on oral anticoagulants (OAC) uptake and pattern of use. Real life data in patients with atrial fibrillation (AF) is important for understanding patient exposure. A cohort study of new OAC users was built to assess trends of drug use from 2011 to 2017, persistence rate, adherence level and its predictors.

METHODS: We built a cohort using the Quebec RAMQ and Med-Echo administrative databases of new adults OAC users within the 1-year following hospitalization with a diagnosis of AF. New users of OAC were defined as no OAC claims in the 1-year prior to cohort entry. Trends of OAC use, persistence rate defined as gap between refills of 30 days, and adherence level defined as the proportion of days covered (PDC) were assessed over a 1-year period following the initiation. Predictors of non-adherence (PDC<80%) were analysed using logistic regression models.

RESULTS: The cohort consisted of 33,311 incident OAC users. The proportions of warfarin claims decreased from 77.9% to 12.7% (2011-2017) of total OAC claims, with direct OACs (DOACs) accounting for 86% of claims for which apixaban and rivaroxaban accounted for 60.1% and 23.4%, respectively. After OAC initiation, the persistence rates ranged from 49.1% to 70.6%; the highest rate was with the high dose of apixaban and the lowest one with warfarin. Approximately 75% of incident OAC users were considered ‘adherent’ (PDC ≥ 80%) with mean PDC of 95.6 to 98.1% compared to ‘non-adherent’ varying between 43.1 and 50.7%. Older age, female gender, higher CHA₂DS₂-VASc score, prior stroke and treatment for chronic cardiovascular disease drugs were associated with high adherence levels.

CONCLUSIONS: The uptake of DOACs increased overtime, accounting for 86% in 2017. In our study, 25% of new OAC users presented a low adherence level. Adherence to OACs remains a significant challenge in patients with AF.