Thromboembolism and mortality in the Tasmanian Atrial Fibrillation Study

Background: Although utilization of anticoagulation in patients with atrial fibrillation (AF) has increased in recent years, contemporary data regarding thromboembolism and mortality incidence rates are limited outside of clinical trials. This study aimed to investigate the impact of the direct oral anticoagulants (DOACs) on the clinical outcomes of patients with AF included in the Tasmanian Atrial Fibrillation Study.

Methods: The medical records of all patients with a primary or secondary diagnosis of AF who presented to public hospitals in Tasmania, Australia, between 2011 and 2015, were retrospectively reviewed. We investigated overall thromboembolic events (TEs), ischemic stroke/transient ischemic attack (IS/TIA), and mortality incidence rates in patients admitted to the Royal Hobart Hospital, the main teaching hospital in the state. We compared outcomes in 2 time periods: prior to the availability of DOACs (pre-DOAC; 2011 to mid-2013) and following their general availability after government subsidization (post-DOAC; mid-2013 to 2015).

Results: Of the 2390 patients with AF admitted during the overall study period, 942 patients newly prescribed an antithrombotic medication (465 and 477 from the pre-DOAC and post-DOAC time periods, respectively) were followed. We observed a significant decrease in the incidence rates of overall TE (3.2 vs 1.7 per 100 patientyears [PY]; P < .001) and IS/TIA (2.1 vs 1.3 per 100 PY; P = .022) in the post-DOAC compared to the pre-DOAC period. All-cause mortality was significantly lower in the post-DOAC period (2.9 vs 2.2 per 100 PY, P = .028). Increasing age, prior stroke, and admission in the pre-DOAC era were all risk factors for TE, IS/TIA, and mortality in this study population. The risk of IS/TIA was more than doubled (hazard ratio: 2.54; 95% confidence interval: 1.17-5.52) in current smokers compared to ex- and nonsmokers.

Conclusion: Thromboembolic event and all-cause mortality rates were lower following the widespread availability of DOACs in this population.