Medication adherence to direct anticoagulants in patients with non-valvular atrial fibrillation – A real world analysis

Abstract

Introduction

Direct oral anticoagulants (DOACs) changed the landscape of atrial fibrillation (AF) treatment, but also brought with them new challenges in terms of accessibility and compliance. The purpose of this study was to assess adherence to DOACs, and its determinants in a population of AF patients.

Methods

Single-center retrospective study including all patients with non-valvular AF treated with a DOAC from the outpatient general cardiology list at a tertiary center, whose first DOAC prescription was between 1 April 2016 and August 2018. The number of pharmacy refills from the day of first prescription to 31 August 2018 was counted (by means of an electronic prescription platform). Medication refill adherence (MRA) was calculated by dividing the total days' supply by the number of days under therapy. Non-compliance was defined as MRA <90%.

Results

A total of 264 patients (120 men, mean age 74 ± 12 years) met the inclusion criteria. The median CHA₂DS₂VAS_C score was 3 (interquartile range (IQR) 2-5) and the median HAS-BLED was 1 (IQR 1-2). Rivaroxaban, apixaban, dabigatran and edoxaban were prescribed in 45%, 41%, 24% and 13% of patients, respectively. During the study 51 patients (19%) used at least two DOACs .Patients took DOACs for a median period of 439 days (IQR 269-638), during which the included population adhered to therapy 90% of the time (IQR 75-100%). Half of the patients (51%) were classified as non-compliant; therapy duration (adjusted odds ratio 1.06 per month, 95% confidence interval (CI) 1.03-1.08, p<0.001), DOACs twice daily (adjusted OR 1.73, 95%CI 1.08-2.75, p=0.022), and higher out-of-pocket costs (adjusted OR 2.13, 95%CI 1.28-3.45, p=0.003) were independent predictors of non-compliance.

Conclusion

Half of the patients (51%) were classified as non-compliant (medication refill adherence <90%). Therapy duration, DOACs twice daily and higher out out-of-pocket costs were independent predictors of non-compliance, which could be targets to improve patient adherence.