UTILIZATION PATTERNS OF NON-VITAMIN K ANTAGONIST ORAL ANTICOAGULANTS IN ELDERLY PATIENTS WITH ATRIAL FIBRILLATION WHO FAILED WARFARIN THERAPY

• Published in: Value in health Vol. 20; no. 5; p. A277
• Main Authors: Han, S, Jeong, HS, Kim, HT, Suh, HS
• Format: Journal Article
• Language: English
• Published: Lawrenceville Elsevier Science Ltd 01-05-2017
• Subjects: Antagonist drugs; Anticoagulants; Atrial fibrillation; Bleeding; Cardiac arrhythmia; Confidence intervals; Dosage; Drug use; Fibrillation; Geriatrics; Health insurance; Hostility; Inappropriateness; Inpatient care; Medical diagnosis; Older people; Patients; Pharmacy; Vitamin K; Warfarin
• ISSN: 1098-3015; 1524-4733
• DOI: 10.1016/j.jval.2017.05.005

OBJECTIVES: To assess drug utilization pattern of non-vitamin K antagonist oral anticoagulants (NOACs), including potentially inappropriate dosing, switching, and concomitant use of contraindicated drugs. METHODS: We used nationally representative data named Health Insurance Review and Assessment Service-Aged Patient Sample 2014 that contained medical and pharmacy claims of approximately 1 million elderly patients aged 65 or older. We included patients who had at least one diagnosis of atrial fibrillation (AF) and had at least one prescription of NOACs (apixaban, dabigatran, or rivaroxaban) between January 1, 2014 and December 31, 2014. Switching was denned as initiating another NOAC and using it ≥ 8 days. Contraindicated drugs were defined according to package insert of each NOAC. Logistic regression model was used to assess factors associated with concomitant use of contraindicated drug. RESULTS: We identified 1,234 elderly patients with AF treated with apixaban (n=106), dabigatran (n=593), and rivaroxaban (n=535). The proportion of potentially inappropriate dosing was the highest in rivaroxaban users (16.9%), followed by dabigatran and apixaban users (9.3% and 0.9%, respectively). Switching occurred in 5.4%, 2.6%, and 0.9% of patients treated with dabigatran, rivaroxaban, and apixaban, respectively. Among 1,234 patients, 236 patients (19.1%) were prescribed contraindicated drugs. The concomitant use of other oral anticoagulants was relatively frequent. Clinic • hospital compared with tertiary hospital (odds ratio (OR): 2.434; 95% confidence interval (CI): 1.215-4.876) and outpatient setting compared with inpatient setting (OR: 4.718; 95% CI: 3.692-6.028) were significantly associated with concomitant use of contraindicated drugs. CONCLUSIONS: Among 1,234 elderly AF patients using NOACs in 2014, 11.8% were not treated with appropriate dosing and 19.1% were prescribed contraindicated drugs that could affect bleeding risk and treatment effectiveness. Furthermore, NOACs use in clinic * hospital or in outpatient setting was significantly associated with concomitant use of contraindicated drugs. Therefore, careful monitoring is warranted for these patients.