Leaders: Preventing Hemorrhage Through Research, Team Care

Dr. Margaret Fang, the medical director of the Anticoagulation Clinic at the University of California, San Francisco, has spent the past several years studying ways to prevent hemorrhage in older Americans through proper anticoagulation therapy. As a member of the Kaiser Permanente of North California ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation) Study Group, she is investigating thromboembolic and hemorrhagic outcomes among more than 13,000 atrial fibrillation patients. Most recently, she and her research collaborators developed and evaluated a new risk stratification scoring system to assess the likelihood of anticoagulant-related bleeding in atrial fibrillation patients. (J. Am. Coll. Cardiol. 2011; 58: 395-401).

In an interview with Hospitalist News, Dr. Fang explained some of the recent findings from the ATRIA Study Group and offered her views on the best role for hospitalists in assuring proper anticoagulation therapy.

Hospitalist News: In a recent study, your team evaluated a tool to assess the risk of bleeding in atrial fibrillation patients. How would that tool be used clinically?

DR. FANG: We developed a bleeding risk score called the ATRIA bleed score. It’s specifically designed to be used in patients who are taking anticoagulants. Our goal was to try to use clinical factors to help clinicians and patients estimate the risk of having a major bleeding event while taking an anticoagulant.

There are stroke risk–stratification schemes out there that I think are more widely used in patients who have atrial fibrillation. These are based on their clinical factors and can estimate their annual risk of stroke. Anticoagulants have complications of bleeding too, so it’s important to describe what we think a patient’s risk of bleeding is while on therapy. This score used five fairly easily available clinical factors. Based on whether patients have these risk factors or not, we can counsel them about what their likelihood of having a bleed is in a given year. The range can be as low as less than 1% to nearly 18% per year. Depending on where a patient falls in that risk spectrum and their estimated risk of stroke, you can then decide whether or not it’s worth proceeding with taking anticoagulants.

HN: Do clinicians tend to overestimate bleeding risk?

DR. FANG: I think so. If you look at practice patterns of whether patients with atrial fibrillation are prescribed anticoagulants or not, it shows that almost half of eligible patients are not taking anticoagulants. When you survey physicians as to whether that’s because of a knowledge deficit or something else that’s keeping them from prescribing anticoagulants, the dominant reason is that they think the patient has too high of a bleeding risk or it’s too hard to control or manage the anticoagulants for a given patient. Even though a lot of studies have shown that the consequences of having a stroke are much more severe than the consequences of having a bleed on therapy, a significant proportion of patients with atrial fibrillation are not prescribed anticoagulants.

HN: If the ATRIA bleed score were widely used, would there be more patients who could take advantage of anticoagulation therapy?

DR. FANG: By using this tool, clinicians can find not only the very high-risk patients, but also may be reassured that on average their patients have a lower risk of bleed than what they may have anticipated. They may find that the bleeding risk is not as high as they thought, especially when used in conjunction with a stroke risk scheme.

The other thing to consider is that prescribing anticoagulants will always be a decision that is made with a great deal of patient involvement. So, tools like a stroke risk calculator or a bleeding risk calculator facilitate that discussion and help the patient understand the risks and benefits of therapy.