Background: Adherence to oral anticoagulants (OACs) in patients with atrial fibrillation (AF) is important in preventing stroke. The dominance of retrospective studies using administrative data has led to a lack of data on psychosocial determinants of adherence and prevented comparison of adherence between OAC drug classes. OAC switching is another aspect of adherence that is unexplored.
Methods: A prospective design was utilized to measure AF patients' self-reported adherence and OAC switching, and to identify their clinical, demographic, and psychosocial determinants. Participants were recruited from specialized AF clinics in Canada and followed for up to 2 years. Data were collected via telephone every 3-4 months using a structured survey. Adherence was measured using the Morisky Medication Adherence scale (©MMAS-8).
Results: The included participants (N = 306) were followed for a median follow up time of 14.1 months and had an average of 3.2(SD 1.4) study visits. The mean self-reported adherence on the ©MMAS-8 was 7.28(SD 0.71) for patients receiving care at specialized AF clinics. Older age, experiencing a bleed, and higher satisfaction with the burden of medications were significantly associated with higher adherence. Drug class did not have any significant impact on adherence. 7.8% of the cohort experienced a switch with most of them being from warfarin to DOAC. Taking warfarin as the index medication, experiencing a bleed and older age were significantly associated with higher odds of switching.
Conclusion: Patients with AF reported high adherence to their OAC therapy however being on DOAC may not translate to better adherence compared to VKA. Improving satisfaction with the burden of therapy is important in improving adherence.
Keywords: Adherence; Anticoagulants; Atrial fibrillation; Persistence; Stroke prevention; Switch.
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