Abstract & Commentary
Synopsis: The outpatient bleeding risk index is a means of identifying the potential risk of bleeding in patients with deep venous thrombosis and pulmonary embolism.
Source: Wells P, et al. Arch Intern Med. 2003;163:917-920.
Evidence demonstrates that long-term anticoagulation prevents recurrent thrombosis in patients with idiopathic deep venous thrombosis or pulmonary embolism. Recent studies place the risk of recurrent venous thrombosis at 27% per year, whereas the risk of major hemorrhage while on anticoagulation is 3.7% per year.1
In 1998, Beyth and colleagues developed a modified outpatient bleeding risk index and found that rates of major bleeding at 12 months of anticoagulation were 3%, 12%, and 48% for patients considered low, moderate, and high risk respectively.2 These risk stratifications were based on the original outpatient bleeding risk index by Landefeld3 which found 5 independent risk factors for major hemorrhage—age older than 65 years, history of gastrointestinal bleeding, history of stroke, serious co-morbid condition, and atrial fibrillation. Patients without any of the aforementioned risk factors were considered low risk, whereas those with 1 or 2 risk factors were placed in the moderate category. High-risk patients were those with 3 or more risk factors.
In this prospective study conducted at the University of Ottawa, 222 patients with diagnosed pulmonary embolism or deep venous thrombosis were observed for an average of 18.5 months. These patients were categorized as low, moderate, or high risk based on the 5 factors published by Landefeld et al. Bleeding events were also recorded with major hemorrhage defined as bleeding that led to the loss of 2 units of blood in a 7-day period or bleeding that was life threatening. All other bleeding episodes were classified as minor.
Within the low-risk group there were 128 patients of which there were 7 minor (5.5%) and zero major hemorrhagic events. Also, 92 patients fell into the moderate risk category of which 5 had minor hemorrhage (5.4%) and 5 had major hemorrhage (5.4%). There were only 2 patients in the high-risk category, 1 of which had a minor bleeding episode (50%), and none suffered a major hemorrhage.
Comment by Jonathan Edelson, MD, and Jill Karpel, MD
Previous studies reported the average annual frequency of fatal, major, and minor bleeding during warfarin therapy were 0.6%, 3.0%, and 9.6%, respectively.2-4
The ability to assess patient risk of bleeding may help to identify which patients need closer monitoring of anticoagulation therapy. In addition, patient risk of bleeding may be weighed against the risk of recurrent thrombotic events. Determining whether an individual patient is at high risk for such complications would be of paramount importance in tailoring treatment strategies for patients with deep venous thrombosis or pulmonary embolism.
Dr. Edelson and Dr. Karpel are Pulmonary and Critical Care Fellows at North Shore University Hospital, Manhasset, NY.
References
1. Kearon C, et al. N Engl J Med. 1999;340:901-907.
2. Landefeld CS, et al. Am J Med. 1989;87:153-159.
3. Beyth RJ, et al. Am J Med. 1998;105:91-99.
4. Landefeld CS, Beyth RJ. Am J Med. 1993;95:315-328.
In 1998, Beyth and colleagues developed a modified outpatient bleeding risk index. In this prospective study conducted at the University of Ottawa, 222 patients with diagnosed pulmonary embolism or deep venous thrombosis were observed for an average of 18.5 months.
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