Drinking increases warfarin bleed risk

A study published in Pharmacoepidemiol Drug Safety has found that heavy drinking more than doubles the risk of major bleeding among people taking warfarin, according to a study of 570 adults with a mean age of 70 years. The risk seems to be even higher in people with certain genes.

Patients with Alcohol Use Disorders Identification Test Consumption Questionnaire (AUDIT-C) scores suggesting moderate or severe alcohol misuse and those who reported heavy episodic drinking (5= drinks on an occasion) were approximately twice as likely (odds ratio [OR] 2.10 and 2.36 respectively) to experience major bleeding.

Major bleeding risk was greater in patients showing moderate to severe alcohol misuse who had taken warfarin for at least a year (OR 2.53) than those treated for less than a year (OR 1.13). Similar results emerged with heavy episodic drinking (OR 2.96 and 1.61 respectively). The authors identified certain genetic variants that increased the bleeding-alcohol interaction between 2.60 and 6.48 fold.