Research Activities, October 2013
New review evaluates strategies for predicting and preventing stroke in atrial fibrillation patients
Comparative Effectiveness Research
A new research review by AHRQ's Effective Health Care Program compares tools that evaluate stroke risk factors and available therapies for patients with atrial fibrillation, the most common cardiac arrhythmia seen in clinical practice. Patients with atrial fibrillation have a five-fold increased risk of stroke. It is estimated that up to 25 percent of all strokes in the elderly are a consequence of atrial fibrillation and that these strokes cost Medicare approximately $8 billion annually.
The review finds that, in patients with atrial fibrillation, CHADS2 and CHA2DS2-VASc scores have the greatest discrimination for stroke events among the risk scores reviewed, whereas HAS-BLED provides the best discrimination of bleeding risk. However, additional information is needed to determine how scores should be utilized in clinical practice.
According to the review, initial trials of newer oral anticoagulants, including apixaban and higher-dose dabigatran, show a high strength of evidence for reducing stroke and bleeding events compared with warfarin in patients with atrial fibrillation, though no studies directly compare the new therapies. In addition, the review finds that for patients not suitable for oral anticoagulation therapies, apixaban is more effective and has a better safety and tolerability profile than aspirin in stroke prevention. However, additional studies are required for common clinical scenarios encountered with patients on therapies for stroke prevention, including strategies for patients undergoing invasive procedures, switching among anticoagulant therapies, and starting or restarting anticoagulant therapy in patients with previous major bleeding events.
These findings and others can be found in the research review Stroke Prevention in Atrial Fibrillation at http://go.usa.gov/DX7H.