Abstract 17182: Patterns of Discontinuation for Non-vitamin K Oral Anticoagulants in Atrial Fibrillation: Results From the ORBIT-AF II Registry

Abstract

Background: Oral anticoagulation (OAC) is effective at preventing stroke in patients with atrial fibrillation (AF), yet warfarin is often poorly tolerated. Non-vitamin K oral anticoagulants (NOACs) are as or more effective as warfarin, yet their tolerance and persistence in clinical practice is not known. Methods: We assessed patterns of persistent OAC use among 2,345 AF patients starting on therapy in the ORBIT-AF II registry (71% starting on a NOAC, and 29% on warfarin). Results: By 6 months, 364 (22%) patients started on a NOAC had discontinued or changed initial therapy versus 143 (21%) started on warfarin initially (p=0.5). Among warfarin users, patients who switched or discontinued therapy were of similar age (median ages 72 and 74 vs. 74 for stable users, p=0.7) and CHA2DS2-VASc scores (mean 98 and 3.66 vs. 3.84, p=0.4). Among NOAC users, those who discontinued treatment were younger (median age 68 vs. 73 for those who switched and 72 for stable users; p=0.0004), and lower CHA2DS2-VASc scores (3.02 vs. 3.58 and 3.47, respectively; p=0.0008). The median time to change or discontinuation was more rapid in those started on a NOAC vs warfarin (97 days vs. 122 days, p=0.003). Among those on warfarin at baseline, 7.6% (n=52) were switched to a NOAC within 6 months, whereas transitions from NOAC to warfarin was 2.5% (n=42).Transitions among NOACs occurred in 9.8%, 3.2%, and 5.5% of patients on baseline dabigatran, rivaroxaban, and apixaban, respectively. Physician preference was the most common reason for both OAC and warfarin changes (Table). Drug cost was the primary reason for change of therapy in 15% of NOAC users (vs. 0 for warfarin). Conclusions: At 6-month follow-up, one in five newly started on OAC had discontinued or changed. These rates of change were similar among warfarin and NOAC treated patients. Cost concerns drove discontinuation in a modest number of patients, however, cost concerns were more prevalent in NOAC-treated patients.