Differences in outcomes between oral anticoagulation "new starters" and "switchers" in patients with nonvalvular atrial fibrillation: A pooled analysis of the AMADEUS and BOREALIS trials

Ying Bai; Alena Shantsila; Gregory Y H Lip

doi:10.1002/joa3.12255

Differences in outcomes between oral anticoagulation "new starters" and "switchers" in patients with nonvalvular atrial fibrillation: A pooled analysis of the AMADEUS and BOREALIS trials

J Arrhythm. 2019 Nov 11;35(6):815-820. doi: 10.1002/joa3.12255. eCollection 2019 Dec.

Authors

Ying Bai^{1

2}, Alena Shantsila¹, Gregory Y H Lip^{1

3}

Affiliations

¹ Liverpool Centre for Cardiovascular Science University of Liverpool and Liverpool Heart & Chest Hospital Liverpool United Kingdom.
² Cardiovascular Center Beijing Tongren Hospital Capital Medical University Beijing China.
³ Aalborg Thrombosis Research Unit Department of Clinical Medicine Aalborg University Aalborg Denmark.

Abstract

Background: To explore differences in outcomes between dose-adjusted vitamin K antagonists (VKAs) "new starters" and "switchers" in patients with nonvalvular atrial fibrillation (AF).

Methods: A post hoc analysis was performed to assess the outcome differences between VKA "new starters" and "switchers" in AF patients using pooled individual patient data of AMADEUS and BOREALIS trials.

Results: A total of 4169 AF patients were included in the present analysis, which included 1383 "VKA new starters" and 2786 "VKA switchers". VKA new starters had higher crude rates of all-cause mortality (P = .035) and cardiovascular death (P = .047) compared to switchers. On multivariable Cox regression analysis, both "new starters" and "switchers" showed nonsignificant trends for different risks of stroke/systemic thromboembolism (SE) (hazard ratio (HR): 1.66, 95%CI: 0.95-2.90, P = .08), major bleeding (HR: 1.25, 95% CI: 0.73-2.16, P = .42), and all-cause death (HR: 1.09, 95% CI: 0.75-1.57, P = .65). On Kaplan-Meier analysis, both groups had similar risks of stroke/systemic embolism (P = .09), major bleeding (P = .28), and all-cause death (P = .06).

Conclusions: In this post hoc analysis of clinical trial patients with AF, "new starters" and "switchers" for VKA initiation had nonstatistically significant rates of trial-adjudicated thromboembolism, major bleeding, and all-cause mortality.

Keywords: new starter; switcher; vitamin K antagonists.