Medicine For People!
- Aspirin and Heart Attack
- How Aspirin Reduces Heart Attack Risk
- Understanding the Research
- Who Benefits From Aspirin
- Who Shouldn't Take Aspirin
- Additional Benefits of Aspirin
- Alternatives to Aspirin
- Learn More
- Quick-Look Summary
- Rant O' the Month -- "Purifying" Rashes
- Monroe Street Clinic News -- Influenza Vaccine
"An aspirin a day keeps the heart attack away." We've all heard it, but like most truisms, this one is not always so. If you think you may be having a heart attack, you should call 911 and then immediately chew up and swallow an aspirin tablet before the medics arrive. This will improve your chance of survival. However, if you're taking a baby aspirin every day to prevent a heart attack, it may pose more risk than benefit. This month Medicine for People examines what the medical research says about the power of aspirin to prevent heart attack. If you don't want to know about the research and just want the bottom line, skip down to the Quick-Look Summary at the end of this article.
How Aspirin Reduces Heart Attack Risk
Your blood contains red blood cells and white blood cells. It also carries little objects called platelets, which are about one-eighth the diameter of a red blood cell. These initiate a blood clot by becoming sticky and adhering to each other and to blood vessel walls. Aspirin makes the platelets less likely to stick to each other.
Aspirin reduces the tendency of platelets to adhere to diseased plaque where they can set off a blood clot that blocks blood supply and leads to aheart attack or stroke. Aspirin does not retard the progress ofarteriosclerosis, and it does not reduce the growth of plaque.
Please note that aspirin is the only nonsteroidal anti-inflammatory drug that does this magic. Others such as ibuprofen and naproxin do not help.In fact, if taken with aspirin, they interfere with aspirin's ability to make platelets more slippery.
Understanding the Research
Our knowledge about aspirin and heart attack prevention comes from several studies. These studies made headlines, but, as usual, you need to look beyond the headlines to see what the studies actually said. Here are some questions to ask:
What was overall survival?
One key question is whether or not the overall survival of the people taking aspirin was improved. Since you do not know what you're going to die from, what you want to know is whether your overall chances are better with or without aspirin. This means that after you have given aspirin to half the group and placebo to the other half, you don't just look at heartdisease. You keep it simple. You wait a few years and then count the bodies.
In most, heart attack rates fall but rates of stroke rise. Some people also experience fatal gastrointestinal hemorrhage caused by taking aspirin (see Who Shouldn't Take Aspirin below). The number you want to look at is "all-cause mortality." These studies that only discuss heart attack rates or deaths from heart attack and don't discuss "all-cause mortality" don't tell you what you need to know.
The Physicians Health Study, one of the largest studies on aspirin and heart attack prevention, found that over five years aspirin cut the risk of heart attack by two-thirds, bringing it down to about 31 percent of what itotherwise would have been. This saved about 18 lives over the course of the study. Unfortunately, there were 22 cases of sudden death in theaspirin group compared to only 12 in the placebo group. Total deaths were not statistically different between the aspirin group and the placebo group. Another large study, the Myocardial Infarction Study, failed to show any benefit of aspirin, either in patients who had heart disease or who did not have heart disease.
Did They Use Only Aspirin?
The Physicians Health Study, published in 1989, looked at 22,000 male physicians who were taking an adult "aspirin" (325 mg) every other day. I put aspirin in quotes, because the aspirin they used contained magnesium as well. Numerous studies have shown that people with higher levels of magnesium are less likely to suffer death from heart disease and more likely to survive after a heart attack. So the second question you want to ask when you see a study on aspirin and heart disease is: did they use plain aspirin or did they use a brand such as Bufferin®, which contains magnesium, another heart-friendly agent? If so, you cannot be sure what caused the results.
Do You Fit the Study Population?
If a study shows a benefit to a group of people from some medical intervention, we cannot assume that the benefit extends to all humans of every variety. For example, the Physicians Health Study, a study of men,did show decreased heart attack rate with aspirin (to repeat, there was no change in all-cause mortality). However, a study of women, the Nurses Health Study, found that any dose of aspirin was associated with higher rates of heart attack, stroke and increased mortality. In addition to gender, age is another important factor.
Who Benefits From Aspirin
Aspirin is beneficial if you have a higher than average risk of heartdisease! The research on aspirin is unequivocal when it comes to people who are at high risk of a heart attack. This includes
- anyone who has had a heart attack,
- people with angina pectoris,
- people with diabetes,
- people aged sixty or over with a strong family history of heart disease,
- People with elevated cholesterol and elevated C-reactive protein.
Aspirin's Benefit Depends on Risk
If your risk of a heart attack is estimated to be more than 1.5 percent per year, aspirin is going to reduce those odds, even if you have not had a previous heart attack. If your risk of heart attack is only 0.5 percent per year, the risk of problems from aspirin outweighs any possible benefit.
To get an estimate of your own personal risk of heart disease, click here. By entering your blood pressure, age, sex, and cholesterol profile, you will get an estimate of your risk of heart disease over the next ten years. If you divide the percent by 10, you can get your annual risk and find out if you're better off with or without aspirin.
For you statistics lovers, here are the odds. Determine your annual riskof a heart attack as noted above. For an annual risk of 1.5 percent, ofevery 77 people who take aspirin for five years, one will avoid a heartattack without a major bleeding complication caused by the aspirin. Lowerthe annual risk to 1 percent, and you need to treat 182 people to achievethe same result.
Who Shouldn't Take Aspirin
Taking aspirin is not without risk. If your blood doesn't clot well enough, it may cause bleeding into the gastrointestinal tract or bleeding into the brain. People with history of gastrointestinal bleeding should not take aspirin. People who are taking other anticoagulant drugs should not take aspirin unless their physician advises them to.
People with kidney disease and people taking another nonsteroidalanti-inflammatory drug should not take aspirin.
Aspirin is less effective in people younger than 50 years of age, and less effective in people with low C-reactive protein. C-reactive protein is anindicator of system-wide inflammation and thus of susceptibility to cardiovascular events. For more information, visit the Cleveland Clinic Website.
Some people are hypersensitive to aspirin and will have prolonged bleeding as a result of taking it. They may notice this only with a surgical procedure or a tooth extraction.
Each year the British National Health Service pays about $160 million to care for people hospitalized with adverse reactions to aspirin. This is the most expensive drug in Britain in terms of adverse reactions and costs twice as much as the runner-up drug, furosemide.
Additional Benefits of Aspirin
People who take aspirin and other nonsteroidal anti-inflammatory drugs are a bit less likely to develop cancer of the colon. This has nothing to do with aspirin's anti-clotting ability. Aspirin appears to enhance the cell nucleus' ability to detect abnormal growth and initiate cell suicide.
Aspirin also has an antiviral effect.
Alternatives to Aspirin
The Coronary Drug Project published in the Journal of the American Collegeof Cardiology in 1986 reported on several measures thought to reduce heartdisease. None appeared effective. Nine years after termination of thestudy, however, they looked to see which study participants had survived.Unexpectedly, those patients who had taken niacin proved to be 10 percentless likely to have died than did the placebo group.
In the race to prevent heart disease, aspirin is being given a run for its money by vitamin E. There have been many studies on vitamin E and a good deal of contention in the medical literature as to whether it's beneficial or not. One of the largest studies was the Nurses Health Study, involving 87,000 women between 35 and 60 years of age. These nurses had no historyof cardiovascular disease. Those who took vitamin E supplements containing an average of 200 units of vitamin E for over two years had about 40 percent fewer cases of coronary disease and an all-cause mortality 13 percent lower than nurses who did not take vitamin E.
Numerous studies have showed that people with lower levels of magnesium have higher rates of coronary heart disease. Because the modern diet is relatively magnesium deficient compared to the diet on which we evolved, most people benefit from taking magnesium.
There are a number of other nutrients that can affect heart disease. Most important in my mind are: folic acid, vitamin B6 and vitamin B12, all of which lower homocysteine, an important risk factor for heart disease as well as cancer.
The academic medical centers in the United States call this a small study, but a Welch epidemiology unit looked at 2000 men who had had a heart attack, one-third of whom were advised to eat more fatty fish. Two-thirds received other advice. The only group to benefit was the group told to eat more fatty fish, and this group had a 30 percent reduction in all-cause mortality compared to the other groups. The study author corrected for potential confounding factors such as smoking, weight, etc., but the benefit persisted. In addition, fatty fish, such as tuna and salmon, tend to reduce cholesterol and triglycerides and improve symptoms of arthritis (allowing you to exercise more!!). An Italian group studied 11,000 people who had recently survived heart attack. In addition to optimalpharmacologic treatment, they were given fish oil (about 1000 mg a day of EPA and DHA). Within three months, the death rate in the fish oil group was just 60 percent of what it was in the non-fish oil group.
The Aspirin Wars: Money, Medicine and 100 Years of Rampant Competition by Charles C. Mann has a few minor historical errors but is very readable.Aside from general information about aspirin, you'll learn about the fascinating commercial exploitation of this remarkably successful and still worthwhile drug.
For much more detail on the research on baby aspirin and heart attack, click on this article from the Journal of Scientific Exploration
For people with established heart disease and no reasons not to take aspirin, a baby aspirin a day is often a good idea. Balancing the risk of aspirin with the benefits of aspirin, the net effect on average will be an increase in longevity. However, I advise consulting your physician before going on a long-term aspirin regimen.
People who have never had a heart attack, or people who have a history of kidney disease, ulcers, or who use other non-steroidal anti-inflammatory drugs, are more likely to experience side effects from an aspirin a day than they are to experience benefit. That's right. If you don't already have heart disease, you don't want to take a baby aspirin every day.
There is an important exception to this rule. If you think you may be having a heart attack, call 911 and then immediately chew up and swallow an aspirin tablet before the medics arrive. This will improve your chance of survival.
This month's nomination for the alternative medicine "hall of shame" is the claim that a rash is an attempt by the body to "purify" itself. In case you haven't heard, some health care providers and other pundits espouse the belief that a rash is the body's attempt to rid itself of some toxin or disease process. They base this upon the idea that the skin is an organ of elimination. Although you may sweat out a few odiferous molecules, the kidneys, not the skin, are the major organ of elimination. Ask anyone on kidney dialysis exactly how much of the body's waste products you can eliminate through your skin. It isn't much.
By this theory, if someone's crackpot treatment doesn't cure your rash but makes it worse, they can then tell you, "Oh, this is good. Your body is purifying itself." First, this seems a mighty convenient explanation for a treatment that doesn't work. Second, I've seen not one whit of evidence in support of this idea, either in the medical literature or in my day-to-day practice. Third, the kidney IS an organ of elimination. Are we then to interpret kidney disease as a laudable occurrence because it then indicates that the kidney is getting rid of waste products?
The rashes I see are due to infections of various types, immune or autoimmune reactions, cancers, contact with irritating substances and various other causes -- but not because the body is ridding itself of a toxin. Bah!
Weight Loss Classes
Janet Goldenbogen-Self, RN, our bariatric nurse educator, provides education and support to patients in our "Solutions" weight management program. Choosing the most effective techniques from her ten yearsexperience, she's produced a three-part "Best of the Best" series for people who want both a taste of her more in-depth program "Don't Diet, Live It" and some proven techniques you can put to work now.
- Monday October 18: "What Works "Realistic, achievable, intuitive eating techniques that actually work."
- Monday November 8: "Conquering the Metabolic Syndrome"Using food as medicine, you can reverse high cholesterol, insulin resistance, and metabolic syndrome.
- Monday November 15: "Enjoying the Holidays without Weight Gain"Eating, enjoying, but not gaining at pot lucks, restaurants, dinner parties.
Each class meets from 7 to 9 pm in the office reception area.
Call Janet at 379-8134 to register.
You may have heard that the supply of influenza vaccine is low this year.You newsletter readers are the first to know - we have 80 doses. If you would like to receive the flu vaccine, come to the office between 8:30 am and 4:30 pm weekdays. If you don't mind waiting a few minutes if we are busy, we can get to you without an appointment.
Medicine for People! is published by Douwe Rienstra, MD at Port Townsend, Washington. Edited by Carolyn Latteier.