Studies Suggest Better Approaches to Staying Clot-Free
One trial found gene tests help with standby med warfarin, another shows promise for newer drug
A test that can reveal a person's entire genetic code currently costs about $1,000 -- down from $80,000 a few years ago, said Dr. Joseph Loscalzo, chairman of the department of medicine and physician-in-chief at Brigham and Women's Hospital in Boston. Loscalzo, who also is editor-in-chief of the journal Circulation, said he expects that one day such a test could cost as little as $100.
MedStar's Howard said a person would only need one genetic test to help guide their therapy. After all, genetics do not change.
The picture regarding these tests remains hazy, however. A related study, led by Dr. Stephen Kimmel, of the University of Pennsylvania Perelman School of Medicine, was presented Tuesday at the AHA meeting. The study of nearly 1,000 patients found no significant difference between those whose warfarin dose was based on genetic testing and those with doses set using current guidelines.
In that study, both groups of patients were in the therapeutic sweet spot about 45 percent of the time.
The difference between the two studies might be the other factors beyond genetics that can determine warfarin dosing, said Dr. Patrick Ellinor, a cardiologist at the Massachusetts General Hospital Heart Center.
Those factors can include the age, weight and race of the patient, as well as whether they smoke or have other health risks. "That's just as helpful as the genetic information, and we should be using it," said Ellinor, who also is an associate professor at Harvard Medical School.
Another study suggested a potential substitute for warfarin. The study found that the medication edoxaban does just as good a job preventing stroke and heart attack but with significantly lower risk of bleeding.
The edoxaban study involved more than 21,000 atrial fibrillation patients at nearly 1,400 hospitals in 46 countries.
Edoxaban performed just as well as warfarin in preventing strokes, according to the study, which was published recently in the New England Journal of Medicine and presented at the AHA meeting.
But major bleeding was 20 percent lower among patients taking a high dose of edoxaban and 53 percent lower among those taking a low dose, compared to patients taking similar doses of warfarin.
Compared to warfarin, the high dose of edoxaban was associated with a 14 percent reduction in death by heart attack or stroke, while the low dose was associated with a 15 percent reduction.
"We know this drug is safer than warfarin, particularly at a low dose," said the study's lead author, Dr. Robert Giugliano, a researcher and physician at Brigham and Women's Hospital.