|02-26-2003, 03:29 PM||#1|
Join Date: Jul 2001
Low doses of warfarin cut blood-clot risk, study says
By Daniel Q. Haney
February 25, 2003
BOSTON - Steady low doses of an old-fashioned blood thinner have been shown to dramatically lower the risk of recurring, dangerous blood clots in the legs and lungs, offering the first effective treatment for an estimated 750,000 U.S. victims annually.
3 Until now, there has been no accepted long-term therapy to prevent these sporadic clots from coming back, as they often do. The new study, released yesterday, found that a modest dose of the drug warfarin reduces this risk by two-thirds.
Warfarin, also known as Coumadin, is the standard blood thinner for treating these clots. Typically, the medicine is stopped after a few months because of worry that the standard dose will trigger bleeding.
Dr. Paul Ridker of Boston's Brigham and Women's Hospital, who directed the federally sponsored study, said the treatment costs pennies a day and is easy to administer once the correct dose is determined for each patient.
"It provides an immediate new standard of care, because the current standard is no care," Ridker said. "Physicians should strongly consider switching their patients to long-term treatment to prevent these clots."
The American Heart Association estimates that about 2 million people each year suffer a deep vein thrombosis, a clot in a vein deep in the leg.
The result is painful swelling that becomes life-threatening if the clot floats to the lungs. This complication occurs in about 600,000 people annually, killing 60,000.
More than half of all cases result from surgery or trauma, such as broken bones, and aren't likely to recur.
However, Ridker estimates that 750,000 people each year have a deep vein thrombosis resulting from more obscure causes, often an inherited tendency to spontaneously form unwanted clots. Almost a third of these people get another clot within eight years.
His study compared low-dose warfarin and dummy pills in people at risk for these recurring clots.
It began in 1998 and was scheduled to end in 2005.
However, the early results were so dramatically positive that researchers decided it would be unethical to continue giving people placebos, so the study was stopped in December.
"This disease generally affects younger people, most of whom are otherwise healthy. The issue of how to manage it is a very, very big problem. Anything that reduces the risk is a major advance, and this is one," said Dr. Andrew Schafer, head of medicine at the University of Pennsylvania.
The results will be published in the April 10 issue of the New England Journal of Medicine. They were posted yesterday on the journal's Web site.
Warfarin was introduced in 1954. (It's also a chief ingredient in rat poison.) Several new drugs are in testing that developers hope will be safer or more effective than warfarin.