October 16, 2008; Washington Post
Aspirin Doesn't Prevent First Heart Attack, Stroke
Bayer´s request to extend the labeling of aspirin to include primary prevention denied
Contradicting current recommendations, a new trial finds that aspirin does not reduce the risk of heart attack and stroke for people with diabetes or peripheral arterial disease.
Aspirin clearly is effective in secondary prevention, reducing the risk for people who already have had a heart attack or stroke, said study author Dr. Jill Belch, a professor of vascular medicine at the University of Dundee in Scotland. Her report was published in the online issue of the BMJ.
However, in the study of 1,276 people who had not yet suffered a heart attack or stroke but were at high risk because they had diabetes or peripheral arterial disease (partial blockage of leg arteries), "we found that they did not benefit from daily aspirin," Belch said. The study showed that aspirin is ineffective in primary prevention, she noted.
"The number of heart attacks and strokes was exactly the same over eight years for those taking aspirin and those taking placebo," Belch said.
The same was true of the antioxidants given in the trial, she said, which was no surprise. "All the antioxidant studies over the past 10 years have been negative," Belch said.
Both the American Heart Association and the U.S. government recommend aspirin for people who have not had heart attacks or strokes but are at high risk for cardiovascular trouble because of conditions such as diabetes.
Those recommendations probably should be changed, said Dr. William R. Hiatt, a professor of medicine at the University of Colorado, who wrote an accompanying editorial.
The newly reported study "is consistent with six other studies on primary prevention, and all those studies were negative," Hiatt said.
The current recommendations are based on analysis of studies that found some primary prevention benefit in subgroups, he said. "Overall, if you do not have heart disease, the risk of bleeding outweighs any benefit you get from aspirin," Hiatt said.
The U.S. Preventive Services Task Force recommendation for use of aspirin in people at high risk of heart disease cited five studies that included 50,000 people. But its report noted that "no trial showed a significant all-cause mortality difference between aspirin-treated and control groups."
Hiatt said that he served on an advisory committee of the U.S. Food and Drug Administration that reviewed a request in 2003 by Bayer to extending the labeling of aspirin to include primary prevention in heart disease. "We couldn't support that request," he said.
Advertisements urging people to take aspirin to benefit the heart are accurate for those who already have had an event, both Belch and Hiatt said.
"It works if you've already had a heart attack," Belch said. "But there is no proof for primary prevention, no proof at all."
"The evidence is solid that aspirin should be given to people with known heart disease," Hiatt said. "But the evidence for people who have risk factors for heart disease is different." By Ed Edelson, HealthDay Reporter
more information on aspirin:
=> Aspirin-like drugs are 15th leading cause of death in U.S.
=> FDA Plans Warnings for Over-Counter Pain Relievers
=> Lawmakers question ads for Bayer 'herbal' aspirin
=> UK Government bans aspirin for under-16s
3 November 2009, Yorkshire Post
Daily pill that could be doing more harm than good
By Sheena Hastings
HEALTHY people should not take aspirin to prevent heart attacks because the risks could outweigh the potential benefits, health researchers have warned. A review of studies on use of the drug has concluded that people who do not have obvious cardiovascular disease should abandon their daily tablet.
After carrying out the review, an editorial in The Drugs and Therapeutics Bulletin (DTB) recommends that doctors should reassess all patients taking the drug for prevention of heart disease. The review, covering six separate sets of controlled trials reported that taking aspirin does not prevent cardiovascular disease deaths in people without symptoms of cardiovascular disease (CVD) and can cause serious internal bleeding.
Low-dose aspirin is widely used by people who have already had a heart attack or stroke to help prevent further episodes. This "secondary prevention" approach is known to have real benefit and has become a well-established strategy.
But, since the benefit of aspirin in secondary prevention became established a few years ago, many thousands of people who have no history or symptoms of heart attack or stroke are thought to have taken to popping a small dose of the drug each day as a preventative measure, but without being prescribed it.
Over the last few years, the DTB says various different sets of health guidelines have been issued which recommended aspirin for "primary prevention" of cardiovascular disease in patients showing no symptoms. They included people aged 50-plus with type 2 diabetes and those with high blood pressure.
A study of trials involving 95,000 patients carried out earlier this year warned that taking aspirin where there was no history of heart attack or stroke could do more harm than good. The benefits are much more finely balanced against harm than was previously thought, even in individuals estimated to be at high risk of experiencing cardiovascular events, including those with diabetes or high blood pressure.
In the latest advice, the DTB stresses that patients who already have cardiovascular problems should continue to take aspirin if they have already been prescribed the medication. But the journal calls on doctors to review giving the drug to others, such as diabetics and those with high blood pressure.
"What we know about aspirin is that it makes the blood less sticky," says David Phizackerley of the DTB. "For those with cardiovascular disease it prevents further cardiac events, working by making the blood less sticky, preventing the blood vessels from narrowing further."
The prescribed dosage of aspirin given to patients who have cardiovascular disease and may have already had a stroke or heart attack is 75-100mg a day – a small amount compared to that routinely taken to deal with pain. Trials carried out in 2002 suggested that a low dosage might be of benefit for people who had not suffered a stroke or heart attack.
"But that trial was based on a mixed group of those who had and those who hadn't had a cardiovascular event of some kind," says Mr Phizackerley. "Now we have data showing that for those who haven't had a stroke or heart attack, the benefits are small. Looking at information on those who have taken aspirin but have no symptoms or disease, in other words people who are well, taking aspirin didn't prevent deaths.
"The chance of reducing heart attack, weighed against chances of suffering internal bleeding were almost the same."
Research shows that in people taking aspirin for 6.4 years, it would prevent three cardiovascular events per 1,000 women, and four per 1,000 in men.
But it would cause two and a half women per thousand and three men per 1,000 to suffer serious gastrointestinal bleeding.
The bleeding, if severe, shows in stools and can lead to anaemia or acute illness and the need for blood transfusion. It's caused because a side-effect of aspirin is that it irritates and damages production of the gastric mucosa, or protective layer inside the stomach.
Professor Steve Field, chairman of the Royal College of General Practitioners, called the DTB "an excellent source of independent advice for medical professionals..." and "...Given the evidence, the DTB's statement on aspirin prescription is a sensible one. The Royal College of General Practitioners would support their call for existing guidelines on aspirin prescription to be amended and for a review of patients currently taking aspirin for prevention."
No-one should be taking aspirin unless it is prescribed by a doctor, says Cathy Ross, a senior cardiac nurse at the British Heart Foundation.
"There was some thought a few years ago that it might be beneficial for people over 50 to take the drug, but unless you already have heart disease or circulatory disease the risk of taking aspirin outweighs the benefit. Anyone already prescribed it should continue, though.
"We advise people not to take aspirin daily unless it's prescribed by their doctor."
Ms Ross added that anyone over 40 should, in any event, go to their general practitioner and ask for a cardiovascular risk assessment, which includes checks on blood pressure, cholesterol and blood tests. The results are analysed and the patient is then told what the risk is over the next 10 years of them developing cardiovascular disease.
A result of 20 per cent-plus is high and the patient might be started on drugs to deal with any particular blood pressure /cholesterol /other problems, as well as being recommended lifestyle changes to tackle any weight, smoking, exercise and other issues that could be contributing to the high risk. "Patients whose risk factor is lower are are given advice on healthy lifestyle choices and monitored regularly.
"Most people in the 20 per cent-plus group either take no exercise, smoke, are diabetic or have family history of cardiovascular disease. One noticeable factor, though, is that if a patient doesn't exercise they'll often tell you that their parents didn't either.
"The same goes for diet – if parents eat a diet high in saturated fat, it's unlikely that their children will eat as healthily as they should.
"The best way to reduce your risk of developing cardiovascular disease is to avoid smoking, eat a diet low in saturated fat and rich in fruit and vegetables, and take regular physical activity."