Safety and efficacy of well managed warfarin. A report from the Swedish quality register Auricula

• Published in: Thrombosis and haemostasis Vol. 113; no. 6; p. 1370
• Main Authors: Sjögren, Vilhelm, Grzymala-Lubanski, Bartosz, Renlund, Henrik, Friberg, Leif, Lip, Gregory Y H, Svensson, Peter J, Själander, Anders
• Format: Journal Article
• Language: English
• Published: Germany 2015
• Subjects: Aged; Aged, 80 and over; Anticoagulants - adverse effects; Anticoagulants - therapeutic use; Atrial Fibrillation - blood; Atrial Fibrillation - diagnosis; Atrial Fibrillation - drug therapy; Atrial Fibrillation - epidemiology; Blood Coagulation - drug effects; Drug Monitoring - methods; Female; Hemorrhage - chemically induced; Hemorrhage - epidemiology; Humans; Incidence; International Normalized Ratio; Male; Middle Aged; Predictive Value of Tests; Registries; Retrospective Studies; Risk Factors; Stroke - blood; Stroke - diagnosis; Stroke - epidemiology; Stroke - prevention & control; Sweden - epidemiology; Time Factors; Treatment Outcome; Venous Thromboembolism - blood; Venous Thromboembolism - diagnosis; Venous Thromboembolism - drug therapy; Venous Thromboembolism - epidemiology; Venous Thromboembolism - prevention & control; Warfarin - adverse effects; Warfarin - therapeutic use; Sweden
• ISSN: 0340-6245
• DOI: 10.1160/TH14-10-0859

The safety and efficacy of warfarin in a large, unselected cohort of warfarin-treated patients with high quality of care is comparable to that reported for non-vitamin K antagonists. Warfarin is commonly used for stroke prevention in atrial fibrillation, as well as for treatment and prevention of venous thromboembolism. While reducing risk of thrombotic/embolic incidents, warfarin increases the risk of bleeding. The aim of this study was to elucidate risks of bleeding and thromboembolism for patients on warfarin treatment in a large, unselected cohort with rigorously controlled treatment. This was a retrospective, registry-based study, covering all patients treated with warfarin in the Swedish national anticoagulation register Auricula, which records both primary and specialised care. The study included 77,423 unselected patients with 100,952 treatment periods of warfarin, constituting 217,804 treatment years. Study period was January 1, 2006 to December 31, 2011. Atrial fibrillation was the most common indication (68 %). The mean time in therapeutic range of the international normalised ratio (INR) 2.0-3.0 was 76.5 %. The annual incidence of severe bleeding was 2.24 % and of thromboembolism 2.65 %. The incidence of intracranial bleeding was 0.37 % per treatment year in the whole population, and 0.38 % among patients with atrial fibrillation. In conclusion, warfarin treatment where patients spend a high proportion of time in the therapeutic range is safe and effective, and will continue to be a valid treatment option in the era of newer oral anticoagulants.