Frequency and Determinants of Adherence to Oral Anticoagulants in Stroke Patients with Atrial Fibrillation in Clinical Practice

Background: Vitamin K antagonists (VKAs) and non-VKA oral anticoagulants (NOACs) are beneficial in patients with stroke and atrial fibrillation (AF). However, little is known about frequency and determinants of adherence to NOACs/NKAs in clinical practice. Methods: This is a single-center explorative study from the Novel Oral Anticoagulants in Stroke Patients (NOACISP)-LONGTERM registry. We included consecutive AF-stroke patients treated with NOACs/NKAs and followed up for 3-24 months. Adherence was assessed at follow-up using structured interviews and quantified as the proportion of prescribed doses taken (PDT). Outcome measures were (i) full adherence, (ii)>= 95% adherence and (iii) >= 80% adherence (i.e., PDT 100/>= 95/>= 80%). To explore determinants of full adherence, we compared characteristics of fully and non-fully adherent patients. Results: A total of 218 of 251 (86.9%) patients (48% female, mean age 77.9 +/- .1 years, 78% NOACs; 22% VKAs) were eligible for analysis with a median follow-up of 12 months: fully adherent were 78.4% patients (NOACs 77.1%, VKAs 83.3%, p = 0.35), >= 95% adherent were 95.4% and >= 80% adherent were 97.2%. Fully adherent patients took more pills daily (median (interquartile range) 7 (5-10) vs. 6 (4-8), p = 0.039), had more often previous antithrombotic treatment (70.8 vs. 53.2%, p = 0.023), caregiver-assisted medication administration (54.2 vs. 19.1%, p < 0.001) and functional dependency (32.8 vs. 15%, p = 0.011) than non fully adherent patients. Conclusions: Full adherence was frequent. Patients naive to antithrombotics, taking few pills, which they self-administer, were at the highest risk of nonadherence and may benefit most from adherence-enhancing interventions. (C) 2016 S. Karger AG, Basel