Comprehension of Nonvalvular Atrial Fibrillation and Anticoagulant Adherence in Elderly Patients in a Subcohort Study of the All Nippon Atrial Fibrillation in the Elderly Registry

Abstract

In this subcohort study of the ANAFIE (All Nippon Atrial Fibrillation In the Elderly) Registry enrolling >30,000 Japanese elderly (aged ≥75years) patients with nonvalvular atrial fibrillation (NVAF), we assessed the association between patient comprehension of NVAF and adherence to anticoagulant therapy with clinical outcomes. Data from 1,968 patients evaluated for NVAF comprehension by a questionnaire consisting of 4 key questions, and 2,362 patients who completed the Morisky Medication Adherence Scale-8 questionnaire were analyzed. Overall, NVAF comprehension was low (81.9% had <3 points), and compared with high comprehension (score ≥3), low comprehension (0 points: 42.1%) was associated with poor prognosis, nonsignificantly higher risk of stroke or systemic embolic event (adjusted hazard ratio [aHR] 2.60 [95% confidence interval 0.97 to 6.94, p=0.057]), all-cause death (aHR 1.71 [0.96 to 3.04, p=0.069]), and significantly higher risk of net clinical outcome (composite of stroke/systemic embolic events, major bleeding, and all-cause death) (aHR 1.63 [1.04 to 2.54, p=0.032]). Adherence to anticoagulant therapy assessed by Morisky Medication Adherence Scale-8 was high (64.9% had high adherence; 29.2%, had medium adherence), but compared with high adherence (score 8), low adherence (score <6: 5.9%) was associated with poor prognosis, significantly higher risk of ischemic stroke (aHR 2.95 [1.08 to 8.04, p=0.035]), all-cause death (aHR 1.93 [1.16 to 3.21, p=0.011]), and net clinical outcome (aHR 1.75 [1.12 to 2.75, p=0.015]). Overall, NVAF comprehension and adherence showed a weak correlation to anticoagulant therapy at baseline (correlation coefficient 0.049). In conclusion, low NVAF comprehension and low anticoagulant adherence were associated with poor clinical outcomes in elderly patients with NVAF.