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Is warfarin underused?


Clinical bottom line

A survey of patients with atrial fibrillation in a VA hospital in the USA suggests that use of warfarin is appropriate in most patients with atrial fibrillation


SD Welsbord et al. Is warfarin really underused in patients with atrial fibrillation? J Gen Intern Med 2001 16: 743-749.


The study population was patients with hospital or clinic visit to a VA hospital coded for atrial fibrillation over two years to July 1999. The records were reviewed with regard to appropriateness of warfarin therapy, and possible contraindications for warfarin use. This was essentially done independently by two reviewers.


There were 1,289 patients with a diagnosis of atrial fibrillation, of whom 844 (65%) had received at least one warfarin prescription.

There were 421 patients (mean age 73 years) who had not received a warfarin prescription and who had not dies. Warfarin prescriptions from another source were identified in 54 others, leaving a final 367 patients with no warfarin prescription.

In these 367:

This left 42 patients (11%) who appeared to be reasonable candidates for anticoagulation with warfarin. These 42 patients were extensively reviewed.

In these 42 patients:

Thus only 16 (3.6%) of patients with AF and not on warfarin were judged to be reasonable candidates for warfarin and who did not receive it.


Though historically warfarin has been reported to be underused. This survey suggests that this is not a universal finding and that primary providers may be far more compliant with the standard of care for patients with atrial fibrillation than previously believed.