Anticoagulation with Warfarin Safe for Some, Not for Others

WarfarinThe American College of Chest Physicians guidelines recommend anticoagulation with generic warfarin (Coumadin, Bristol-Myers Squibb) for patients with atrial fibrillation who are 75 years of age or older. But as many as 50% of patients might not be getting the anticoagulation they need to prevent a stroke.

Researchers from Montefiore Medical Center say that this low rate might be a result of physicians’ perceptions about bleeding risk, falls, and the need for frequent laboratory monitoring and dosage adjustments. They conducted a retrospective study to determine how warfarin drugs or acetylsalicylic acid was being used in patients at risk for stroke and hemorrhage, including those with a history of falls or dementia.

Looking at a year’s worth of information on 106 patients, the researchers assessed the prevalence of stroke, hemorrhage, and falls and the possible effects of anticoagulation in dementia. Ninety patients were receiving warfarin, and 16 were taking aspirin.

At 12 months, two of the 90 patients receiving warfarin (order) had a stroke; five patients had major hemorrhage, and 18 had died. Five of 11 patients (45%) with a history of falls and eight of 17 patients (47%) who had dementia died, compared with eight of 65 patients (12%) who had no history of falls or dementia. However, it was unclear whether the higher mortality rate among warfarin (buy) patients with falls was a result of risk factors unde lying a propensity to fall, atrial fibrillation, or warfarin drugs use. In warfarin patients with falls who survived, the prevalence of stroke and major hemorrhage was not significantly higher compared with that for patients not treated with generic warfarin. The data suggest that older adults should be carefully screened for falls as part of the decision-making process about anticoagulants.

The coordination and monitoring in the study might have limited the variability in International Normalized Ratio that can result from polypharmacy, drug interactions, and confusion regarding dose alterations. Ultimately, the debate comes down to quality of life versus reducing the risk of stroke and hemorrhage.

Source: Am J Geriatr Pharmacother 2009;7;159-166