Highlights from

ACC 2019

American College of Cardiology Annual Scientific Session & Expo

New Orleans 16-18 March 2019

Lower rates stroke/SE with DOACs in frail non-valvular AF patients

Results suggest that DOACs are associated with lower rates of stroke/systemic embolism (SE) and varying rates of major bleeding compared with warfarin in frail non-valvular atrial fibrillation (AF) patients [1].

AF is the most common arrhythmia in the elderly, and it is an independent risk factor for stroke [2]. Also, the prevalence of frailty increases steadily with age, from approximately 4% at 65-69 years of age to nearly 26% at 85 years or above [3]. It is estimated that non-valvular AF patients have a 4-times higher odds of being classified as frail than patients without non-valvular AF [4], and despite the high prevalence of AF among frail elderly patients, fewer frail AF patients receive oral coagulants compared with non-frail patients [5,6]. Even so, very few real-world studies have examined the comparative efficacy and safety outcomes between non-vitamin K antagonist oral coagulants (DOACs) and warfarin in the frail elderly non-valvular AF population [7,8].

Prof. Gregory Lip (University of Birmingham, United Kingdom) presented the results of a retrospective, observational study of frail non-valvular AF patients who initiated apixaban, dabigatran, rivaroxaban, or warfarin using Medicare data and 3 US commercial claims databases. Frailty was defined using the algorithm defined by Segal et al. The results showed that among non-valvular AF patients aged ≥65 years (n=258,989), 38% met frailty criteria. They identified 98,375 frail patients with non-valvular AF, including 18.8% on apixaban, 6.4% on dabigatran, 26.1% on rivaroxaban, and 48.7% warfarin patients. The mean frailty indicator score was 0.4. Before propensity score matching (PSM), >90% of patients had CHA2DS2-VASc scores ≥4, and >80% had HAS-BLED scores ≥3. After PSM, 17,750 apixaban-warfarin, 6,204 dabigatran-warfarin, and 24,388 rivaroxaban-warfarin PSM pairs were included in the analysis. The mean follow-up time was 7-8 months. After PSM, all baseline characteristics were balanced between the matched cohorts. Approximately 50.5% of apixaban, 38.6% of dabigatran, and 52.3% of rivaroxaban (10 or 15 mg) patients were on a lower dose (2.5 mg, 75 mg, and 10 or 15 mg, respectively).

Compared with warfarin, all DOACs were associated with a lower risk of stroke/SE. Apixaban and rivaroxaban patients had a lower risk of ischaemic stroke compared with warfarin patients. Apixaban and dabigatran use were associated with a lower risk of haemorrhagic stroke vs warfarin use, and apixaban was associated with a lower risk of major bleeding compared with warfarin. Dabigatran was associated with a similar risk and rivaroxaban was associated with a higher risk of major bleeding compared with warfarin. Gastrointestinal bleeding was the most prevalent type of major bleeding with apixaban being associated with a lower risk and dabigatran and rivaroxaban associated with a higher risk vs warfarin. All DOACs were associated with a lower intracerebral haemorrhage risk vs warfarin.

keywords: non-valvular atrial fibrillation, DOAC, warfarin, stroke, systemic embolism, apixaban, dabigatran, rivaroxaban, arrhythmia

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