Bleeding in patients with atrial fibrillation treated with dabigatran, rivaroxaban or warfarin

Bleeding in patients with atrial fibrillation treated with dabigatran, rivaroxaban or warfarin

European Journal of Internal Medicine 38 (2017) e20 Contents lists available at ScienceDirect European Journal of Internal Medicine journal homepage...

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European Journal of Internal Medicine 38 (2017) e20

Contents lists available at ScienceDirect

European Journal of Internal Medicine journal homepage: www.elsevier.com/locate/ejim

Letter to the Editor Bleeding in patients with atrial fibrillation treated with dabigatran, rivaroxaban or warfarin Keywords: Bleeding risk Atrial fibrillation Direct oral anticoagulants

To the Editor I read with great interest the paper by Ellis et al. [1], which is a retrospective cohort study to determine the incidence of bleeding in patients with atrial fibrillation (AF) beginning dabigatran, rivaroxaban or warfarin during 3-year. Bleeding incidences were calculated per 100 patientyears of treatment, and they were 3.9 (95% confidence interval (CI), 3.6– 4.4) in warfarin patients, 4.2 (95% CI, 3.7–4.7) in dabigatran patients, and 4.1 (95% CI, 3.0–5.3) in rivaroxaban patients. In addition, intracranial hemorrhage (ICH) rates were 0.71 (95% CI, 0.56–0.90) in warfarin patients, 0.4 (95% CI, 0.18–0.87) in dabigatran patients, and 0.27 (95%CI, 0.10–0.80) in rivaroxaban patients. The authors recognized no significant differences in the prevalence of bleeding and ICH in dabigatran and rivaroxaban patients against warfarin patients. I have some queries on their study. First, Lip et al. [2] also conducted a retrospective cohort study to compare the major bleeding risk among patients with apixaban, rivaroxaban, dabigatran or warfarin. They adopted Cox model and adjusted hazard ratios (HRs) (95% CIs) of apixaban, rivaroxaban or dabigatran against warfarin for major bleeding were 0.52 (0.30–0.89), 1.13 (0.91–1.41), or 0.88 (0.64–1.21), respectively. These data were in concordance with those by Ellis et al., and the advantage of apixaban for preventing major bleeding should also be confirmed by further study. Second, Camm et al. [3] investigated the risk of rivaroxaban in patients with nonvalvular AF, and ICH occurred in 0.4 events per 100

patient-years. Tamayo et al. [4] reported that major bleeding in patients with nonvalvular AF treated with rivaroxaban was 2.86 events per 100 person-years, and prevalence of ICH in all major bleeding was under 10%. Coleman et al. [5] reported that ICH occurred in 0.49 events per 100 patient-years in patients treated with rivaroxaban. The prevalence of ICH by rivaroxaban treatment was lower than 0.5 per 100 patientyears, which was also in concordance with data by Ellis et al. [1]. Ellis et al. [1] reported that the number of bleeders in patients with rivaroxaban was 44, and a limited number, especially in ICH, would partly contribute to the lack of significance. Finally, the authors mentioned that past randomized controlled trials (RCTs) showed similar bleeding rates in patients with dabigatran, rivaroxaban and warfarin. The randomized controlled trial has a highest quality of evidence, and a meta-analysis with RCTs is needed to confirm the risk of bleeding by dabigatran, rivaroxaban or warfarin by further study. References [1] Ellis MH, Neuman T, Bitterman H, Dotan SG, Hammerman A, Battat E, et al. Bleeding in patients with atrial fibrillation treated with dabigatran, rivaroxaban or warfarin: a retrospective population-based cohort study. Eur J Intern Med 2016;33:55–9. [2] Lip GY, Pan X, Kamble S, Kawabata H, Mardekian J, Masseria C, et al. Major bleeding risk among non-valvular atrial fibrillation patients initiated on apixaban, dabigatran, rivaroxaban or warfarin: a “real-world” observational study in the United States. Int J Clin Pract 2016;70:752–63. [3] Camm AJ, Amarenco P, Haas S, Hess S, Kirchhof P, Kuhls S, et al. XANTUS: a real-world, prospective, observational study of patients treated with rivaroxaban for stroke prevention in atrial fibrillation. Eur Heart J 2016;37:1145–53. [4] Tamayo S, Frank Peacock W, Patel M, Sicignano N, Hopf KP, et al. Characterizing major bleeding in patients with nonvalvular atrial fibrillation: a pharmacovigilance study of 27,467 patients taking rivaroxaban. Clin Cardiol 2015;38:63–8. [5] Coleman CI, Antz M, Bowrin K, Evers T, Simard EP, Bonnemeier H, et al. Real-world evidence of stroke prevention in patients with nonvalvular atrial fibrillation in the United States: the REVISIT-US study. Curr Med Res Opin 2016;32:2047–53.

Tomoyuki Kawada Department of Hygiene and Public Health, Nippon Medical School, Japan E-mail address: [email protected]

http://dx.doi.org/10.1016/j.ejim.2016.11.016 0953-6205/© 2016 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

27 November 2016