The relative cost-effectiveness of anticoagulants: obvious, except for the cost and the effectiveness.

The search for a safer and more tolerable anticoagulant alternative to warfarin has been the holy grail of thromboembolic research for decades. With its capacity to reduce the risk of ischemic stroke by nearly two thirds in patients with atrial fibrillation, warfarin remains one of the most powerful preventive tools in all of medicine.1 But in the 57 years since the drug was introduced, generations of clinicians and patients have become all too familiar with the difficulty of establishing and maintaining an adequate level of the international normalized ratio (INR) in the face of intercurrent illnesses, the use of myriad interacting drugs, and dietary changes. Partly as a result, anticoagulation remains woefully underused in patients for whom it could do enormous good.2 Sensitive to problems that result from commission more than from omission, physicians often overestimate the likelihood of hemorrhagic complications and underestimate the consequences of failing to prevent embolic events.3