Efficacy and safety of non-vitamin K antagonist oral anticoagulants compared with warfarin in patients with atrial fibrillation

AIMS: Non-vitamin K antagonist oral anticoagulants (NOACs) were in pivotal randomised controlled trials at least non-inferior to warfarin for stroke prevention in atrial fibrillation, but time in therapeutic range (TTR) for warfarin was lower (mean 55%-65%) than in Swedish general care where TTR is >70%. We compared efficacy and safety of NOACs and warfarin treatment for stroke prevention in Sweden. METHODS: Retrospective cohort study of all non-selected oral anticoagulation naïve atrial fibrillation patients with first prescription for NOACs or warfarin between December 2011 and December 2014, excluding patients with mitral stenosis or mechanical valvular prosthesis. Data were obtained from cross-linked national registers, propensity scores were used as continuous covariates, and associations between treatment and outcomes were evaluated by multivariable Cox regressions. RESULTS: -VASc points (mean) 3.38 vs 3.24, p<0.001, in NOAC and warfarin groups, respectively. HRs (95% CI) for NOACs versus warfarin were 1.04 (0.91-1.19) for all-cause stroke or systemic embolism, 1.16 (1.00-1.35) for ischaemic stroke, 0.85 (0.76-0.96) for major bleeding, 1.22 (1.01-1.46) for gastrointestinal bleeding, 0.60 (0.47-0.76) for intracranial haemorrhage and 0.89 (0.81-0.96) for all-cause mortality. CONCLUSION: In this large non-selected anticoagulation naïve Swedish atrial fibrillation cohort, the risks for all-cause stroke or systemic embolism were similar with NOACs and warfarin, but NOACs were associated with significantly lower risks of all-cause mortality, major bleeding and intracranial haemorrhage but higher risk of gastrointestinal bleeding. Better safety suggests NOACs as preferred treatment for patients with atrial fibrillation starting oral anticoagulation