Abstract 14100: Oral Anticoagulant Discontinuation in Patients With Nonvalvular Atrial Fibrillation
Objective: To identify factors associated with discontinuation of oral anticoagulants among patients with non-valvular atrial fibrillation (NVAF).
Methods: A retrospective cohort study was conducted using the MarketScan insurance claims database from Oct 2010 to Jul 2012. Patients were eligible if they newly initiated an oral anticoagulant in the study period, were ≥18 years old, had a diagnosis of AF (ICD-9 code 427.31 or 472.32), and had at least 6 months of continuous enrollment after oral anticoagulant initiation. Patients were excluded if they had valvular heart disease or cardiac surgery during the 12 month pre-index period. Patients were followed until an interruption in continuous enrollment, a switch or discontinuation of index treatment, or end of the study, whichever occurred earliest. Discontinuation was defined as no prescription for index drug within 60 days of last days’ supply of last prescription. Multivariate Cox proportional hazards regression was used to assess factors associated with discontinuation. Adjusted hazard ratios (HR) and 95% confidence intervals (CI) were reported.
Results: Among 12,129 eligible patients, 8,143 (67.1%) were on warfarin and 3,986 (32.9%) on novel oral anticoagulants (NOACs): dabigatran or rivaroxaban. Of these, 304 (2.5%) patients switched oral anticoagulants during follow-up and were excluded from the analysis. Overall, 47.3% of patients discontinued during follow up with mean time to discontinuation of 120 days. After adjusting for demographic and clinical covariates, patients taking NOACs vs. warfarin (HR= 0.91, CI: 0.86-0.97), older patients (≥65 vs. 18 to 34, HR=0.32, CI: 0.24-0.43), those with diabetes (HR= 0.84, CI: 0.77-0.90), prior stroke/TIA (HR= 0.65, CI: 0.56-0.75), prior PE (HR= 0.71, CI: 0.58-0.88), and CHF (HR= 0.80, CI: 0.74-0.87) statistically less likely to discontinue. Patients with prior bleeding events were significantly more likely to discontinue (HR= 1.20, CI: 1.08-1.34).
Conclusion: The risk of discontinuation of oral anticoagulant treatment among NVAF patients was high. Patients on NOACS compared to warfarin and those with several comorbid conditions had significantly lower risk of discontinuation, while those with prior bleeding were more likely to discontinue.
- © 2013 by American Heart Association, Inc.