A blood thinner that works slightly better than cheap aspirin at preventing repeat heart attacks or strokes is not worth the extra cost when used long term, a study concludes.
But heart doctors say the analysis is speculative and does not reflect how the medicine is used today.
Researchers looked at aspirin at 4 cents, the drug Plavix at $3.22 a pill and a combination of the two to figure out their cost-effectiveness in treating heart disease.
Using aspirin alone was cost-effective, while using Plavix alone or with aspirin was not, they reported in Thursday's New England Journal of Medicine.
Cardiologist Dr. Eric Topol, however, said it is premature to make such an assessment because long-term use of Plavix has not been tested in patients and the medicine is not prescribed that way.
``It's only recommended at the current time for nine months of therapy, whereas this analysis is assuming a lifelong therapy,'' said Topol, who is from the Cleveland Clinic and took part in one Plavix study.
Like aspirin, Plavix, also known as clopidogrel, keeps blood platelets from sticking together and forming clots. It has been shown to work somewhat better than aspirin, which cuts the risk of heart attack, stroke or death by 30 percent in people with heart disease.
Topol said Plavix is generally used for 30 days after an angioplasty, and guidelines issued in March recommend it for 90 days after chest pain or a mild heart attack.
For the analysis, Dr. Lee Goldman and his colleagues used a computer model of the U.S. population over 35 with heart disease. They predicted how many people would have heart attacks, strokes or die over the next 25 years and what it would cost to treat them. They factored in operations, hospital stays and the added cost of living longer because of the drugs' benefits.
They calculated how much it would cost for each year of life gained. Aspirin used alone was considered cost-effective at $11,000 per year of life gained. Plavix used alone or combined with aspirin was deemed ``financially unattractive'' at $130,000 per year gained.
The researchers said the cost of Plavix would have to drop to 60 cents to $1 to bring the cost per year gained down to $50,000, the level they used as a benchmark.
``You or I might well say that we think our own lives are worth more than that,'' said Goldman, of the University of California at San Francisco. ``The question is: Would we pay for it out of our own funds or would we want to pay for someone else out of our own funds? That's where the debates take place.''
Another cardiologist, Dr. Christopher Cannon of Brigham and Women's Hospital in Boston, said the current use of Plavix is focused on high-risk patients. ``When you treat high-risk patients for short periods of time, then it becomes cost-effective,'' he said.
Bristol-Myers Squibb Co., which markets Plavix with Sanofi-Synthelabo, said the drug has been used by 11 million worldwide since it was approved in 1997. Spokeswoman Caroline Almeida said the company believes Plavix is ``priced comparably with other innovative medicines.''