One in three AF patients at high risk of stroke are not being prescribed VKA therapy

New data show that, worldwide, one in three patients with atrial fibrillation (AF) who are at high risk for stroke are not being prescribed anticoagulant therapy, particularly vitamin K antagonists (VKA) – medicines known to significantly lower stroke risk in these patients.  The findings are from the first cohort of the GARFIELD (Global Anticoagulant Registry in the Field) – an innovative research initiative being conducted by the Thrombosis Research Institute (TRI) to understand the global burden of AF, a common condition in which the two small upper chambers of the heart (the atria) quiver rather than beat rhythmically and can lead to life-threatening complications, including stroke.  

The first analysis of cohort one included 9,288 patients newly-diagnosed with AF and with at least one additional risk factor for stroke from 19 countries in the Americas, Europe, Asia, and Asia Pacific. Of these patients, 81 percent had a high risk for stroke based on a score > or = 2 on CHA2DS2-VASc, a detailed assessment of stroke risk in AF patients based on eight known risk factors. Treatment guidelines recommend that all patients with a CHA2DS2-VASc or a CHADS2 risk score > or = 2 be prescribed anticoagulation therapy with VKAs, unless contraindicated, for example because of a risk of excessive bleeding.  Whilst 81 percent of newly diagnosed patients had a CHA2DS2-VASc risk score > or = 2, only 64 percent of the high-risk patients in this cohort received any anticoagulant therapy. According to CHADS2, 55 percent of newly diagnosed patients were at high risk for stroke out of which 33 percent did not receive any anticoagulant therapy.

"We know that atrial fibrillation carries a significant stroke risk and anticoagulants can reduce that risk by more that 60 percent; however, GARFIELD data suggest a lower utilization than would be anticipated based on clinical trial evidence and current treatment guidelines," said Professor Ajay Kakkar, Director of the TRI, and Professor of Surgery, University College London.  "Too many patients remain unprotected, and understanding the reasons for this will help in the appropriate adoption of innovative strategies to prevent stroke and improve clinical outcomes."

According to the treating physicians, among patients in the entire cohort:

• The main reason cited for patients not receiving VKAs was “physician choice” (37%); fewer cited reasons such as low stroke risk (13%); excessive bleeding risk (7%) or history of previous bleeding event (2%)
• Overall 25% of patients were not prescribed an anticoagulant but received an antiplatelet drug such as aspirin alone which has proven less effective in lowering stroke risk in patients at high risk for stroke as an anticoagulant, (1) ; of these patients
  • 77% had a CHA2DS2-VASc > or = 2
  • 49% had a CHADS2 score > or = 2
• In 13 percent of patients neither antiplatelet nor anticoagulant therapy were prescribed
  • 73% of these patients had a CHA2DS2VASC score > or = 2
  • 43% of these patients had a CHADS2 score > or = 2

"GARFIELD is the largest, global disease registry that will provide us with a unique real-world view of the effectiveness and impact of current and future AF management," said Professor Jean-Pierre Bassand, Professor of Cardiology at the University of Besancon Franche-Comte. "GARFIELD is a prospective Registry in which clinical sites are going to be representative of national care settings who are managing AF patients in the long term. This will allow us to get a most complete view on how AF is being managed in real-world clinical practice rather than in expert centers and experienced research sites."