Stroke-Preventive Drug Underused
WebMD News Archive
Dec. 20, 1999 (Atlanta) -- Erring on the side of caution, most doctors fail
to give patients with atrial fibrillation a drug that can greatly reduce their
risk of stroke. A new study shows that four out of 10 eligible patients still
don't get the drug, although it does show HMOs that offer doctors better
support can increase proper treatment.
Atrial fibrillation is a condition in which the heart tends to beat out of
rhythm. There are several types of treatment, but patients remain at high risk
of stroke. A blood-thinning drug marketed as warfarin sodium or Coumadin
greatly reduces this risk, but doctors often are reluctant to prescribe it.
"We are actually encouraged, in part, by our findings, because in the
rest of the country only a third of patients are getting it," the lead
author of the study, Alan S. Go, MD, tells WebMD. "More work needs to be
done to improve its use. Patients with atrial fibrillation should at least
consult with their doctor to see if they're candidates to take it."
The Anticoagulation and Risk Factors in Atrial Fibrillation Study (ATRIA)
analyzed patients enrolled in the Kaiser Permanente Medical Care Program in
northern California. The over 11,000 patients eligible for warfarin therapy
during the study period had one or more risk factors for stroke. Only 59% of
these patients received warfarin therapy. Even among patients considered ideal
candidates -- aged 65-74 years with heightened risk due to previous stroke,
hypertension, or both -- only 62% received the drug.
"We don't know the exact reasons why patients were not placed on
warfarin therapy, except for patients who refused and patients with underlying
risk [of adverse effects]," Go says. "Even with that limitation, it is
unlikely that explains all the eligible patients who were not receiving
Randall S. Stafford, MD, PhD, and Daniel Singer, MD, have studied national
patterns of warfarin use in atrial fibrillation. They found that during the
1980s, when the drug's stroke-reduction benefits first became known, use
increased greatly -- to as many as 40% of eligible patients -- but then leveled
off. In an interview to provide objective comment, Stafford tells WebMD that
physician reluctance to provide warfarin stems from fear of doing harm.
"When physicians think about using warfarin and assess the risks and
benefits, there may be tendency to overemphasize the risk and undervalue the
benefit," says Stafford, assistant professor at the Institute for Health
Policy at Massachusetts General Hospital in Boston. "That's because the
benefit [of warfarin therapy] is in prevention, and you never know who didn't
[go on to] have a stroke. But in terms of the risk, you see it and you know you
caused it. Physicians want to be careful about causing harm to