Risk of hemorrhage from warfarin higher in clinical practice than clinical trials show

Rates of hemorrhage for older patients on warfarin therapy are much higher than rates reported in clinical trials, found a study published in CMAJ (Canadian Medical Association Journal).

"The rate of hemorrhage in our study is considerably higher than those reported in of warfarin therapy, which have ranged between 1% and 3% per person-year," writes lead author Tara Gomes, Institute for Clinical Evaluative Sciences (ICES), Toronto, with coauthors.

Warfarin, a commonly used blood thinner, is used to treat patients with atrial fibrillation to help prevent stroke and blood clots.

The study looked at 125,195 patients in Ontario aged 66 years or older with atrial fibrillation who started warfarin between Apr. 1, 1997 and Mar. 31, 2008. The overall risk of hemorrhage over the 13-year study period was 3.8% per person-year but was 11.8% in the first 30 days of therapy. For people older than 75 years, the overall risk was 4.6% compared with 2.9% for younger people.

Hemorrhage was defined as major bleeding requiring a visit to the emergency department or admission to hospital. Most admissions to hospital involved gastrointestinal hemorrhages (6785, or 63%). Almost 1 in 5 people (1963, or 18%) admitted to hospital for hemorrhages died in care or within a week after discharge.

"There are currently no large studies offering real-world, population-based estimates of rates among patients taking , which are needed for future comparisons with new anticoagulant agents once they are widely used in routine clinical practice," the authors write.

More information: www.cmaj.ca/lookup/doi/10.1503/cmaj.121218

Related Stories

Blood-Thinning Drug Linked to Increased Bleeding in Brain

date Sep 29, 2008

(PhysOrg.com) -- Patients who take the commonly used blood-thinning drug warfarin face larger amounts of bleeding in the brain and increased risk of mortality if they suffer a hemorrhagic stroke, new research from the University ...

Recommended for you

Cognitive impairment predicts worse outcome in heart failure

date May 24, 2015

Cognitive impairment predicts worse outcome in elderly heart failure patients, reveals research presented today at Heart Failure 2015 by Hiroshi Saito, a physiotherapist at Kameda Medical Centre in Kamogawa, Japan. Patients ...

1950s drug is future heart treatment

date May 22, 2015

Oxford University researchers have found a promising future treatment for heart disease, going back to a drug first developed in 1950.

Time is muscle in acute heart failure

date May 21, 2015

Urgent diagnosis and treatment in acute heart failure has been emphasised for the first time in joint recommendations published today in European Heart Journal.

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.