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.

1. Lip GYH, et al. J Am Coll Cardiol. 2019;73(9):432. DOI: 10.1016/S0735-1097(19)31040-X.
2. Fumagalli S, et al. Aging Clin Exp Res. 2010;22(2):129-133.
3. Song X, et al. J Am Geriatr Soc. 2010;58(4):681-7.
4. Polidori A, et al. Arch Gerontol Geriatr. 2013;57(3):325-7.
5. Oqab Z, et al. J Atr Fibrillation. 2018;10(6):1870.
6. Induruwa I, et al. Geriatr Gerontol Int. 2017;17(11):2178-2183.
7. Martinez BK, et al. J Am Heart Assoc. 2018;7(8):e008643.
8. Ozaki M, et al. J Am Coll Cardiol. 2018;71(11):A286.

Posted on 6 June, 201916 February, 2024