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.

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 ( = .035) and cardiovascular death ( = .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,  = .08), major bleeding (HR: 1.25, 95% CI: 0.73-2.16,  = .42), and all-cause death (HR: 1.09, 95% CI: 0.75-1.57,  = .65). On Kaplan-Meier analysis, both groups had similar risks of stroke/systemic embolism ( = .09), major bleeding ( = .28), and all-cause death ( = .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.