Safety and efficacy of well managed warfarin

Abstract

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.

Risk of Recurrent Stroke and Death After First Stroke in Long‐Distance Ski Race Participants

“…The effectiveness of anti–vitamin K treatment and compliance is generally very high in Sweden. There is likely no difference between skiers and nonskiers 16. After adjustment for confounders such as socioeconomic data and smoking, the association remained essentially unchanged for death but the risk for recurrent stroke was similar for skiers and nonskiers.…”

Validation of a Modified CHA 2 DS 2 -VASc Score for Stroke Risk Stratification in Asian Patients With Atrial Fibrillation

“…8 The treatment threshold with vitamin K antagonist may even be lower with good quality anticoagulation control, where a high time in therapeutic range (>70%) is achieved, given that a high time in therapeutic range is associated with best efficacy and safety related to vitamin K antagonists. [22][23][24] All clinical risk scoring systems have broadly comparable predictive value for identifying high-risk patients who sustain stroke events. Rather than a categorized approach to stroke risk stratification focusing on high-risk patients, a simple approach to thromboprophylaxis is to initially identify truly low-risk patients in whom OACs could be clearly omitted.…”

Should Patients With Atrial Fibrillation and 1 Stroke Risk Factor (CHA 2 DS 2 -VASc Score 1 in Men, 2 in Women) Be Anticoagulated?

“…[36][37][38][39] Of note, real-world studies show that good average individual TTR (ie, good-quality anticoagulation control, average TTR >70%) is associated with low stroke and bleeding risks. 40,41 This approach would avoid a trial of VKA (or warfarin stress test), which may put patients at risk of thromboembolism as a result of poor TTRs in the initial inception phase. 42 Those patients with a SAMe-TT 2 R 2 score >2 can be flagged for education and more regular review or follow-up to ensure good anticoagulation control or can be offered an NOAC (Figure 2).…”