Non-Vitamin K oral anticoagulants are non-inferior for stroke prevention but cause fewer major bleedings than well-managed warfarin: A retrospective register study

Abstract

Background For patients with atrial fibrillation, non-vitamin K oral anticoagulants, or NOACs (dabigatran, rivaroxaban, edoxaban, and apixaban) have been proven non-inferior or superior to warfarin in preventing stroke and systemic embolism, and in risk of haemorrhage. In the pivotal NOAC studies, quality of warfarin treatment was poor with mean time in therapeutic range (TTR) 55–65%, compared with 70% in Swedish clinical practice. Methods We compared NOACs (as a group) to warfarin in non-valvular atrial fibrillation, studying all 12,694 patients starting NOAC treatment within the Swedish clinical register and dosing system Auricula, from July 1, 2011 to December 31, 2014, and matching them to 36,317 patients starting warfarin using propensity scoring. Endpoints were thromboembolic events and major bleedings that were fatal or required hospital care. Outcome data were collected from validated Swedish hospital administrative and clinical registers. Results Mean age was 72.2 vs 72.3 years, proportion of males 58.2% vs 57.0%, and mean followup time 299 vs 283 days for NOACs and warfarin. Distribution of NOACs was: dabigatran 40.3%, rivaroxaban 31.2%, and apixaban 28.5%. Mean TTR was 70%. There were no significant differences in rates of thromboembolic/thrombotic events or gastrointestinal bleeding. NOAC treated patients had lower rates of major bleeding overall, hazard ratio 0.78 (95% confidence interval 0.67–0.92), intracranial bleeding 0.59 (0.40–0.87), haemorrhagic stroke 0.49 (0.28–0.86), and other major bleeding 0.71 (0.57–0.89). Conclusion For patients with atrial fibrillation, NOACs are as effective for stroke prevention as well-managed warfarin but cause fewer major bleedings.