WHICH DRUG IS BETTER AT HEART ATTACK PREVENTION:
ASPIRIN OR A STATIN?

By Maryann Napoli
(December 2002)

Early this year, the U.S. Preventive Services Task Force published a summary of all the scientific evidence supporting the use of aspirin for the primary prevention of heart attacks (Annals of Internal Medicine, 1/15/02). A co-author of this summary, Michael Pignone, MD, MPH, University of North Carolina at Chapel Hill, is interviewed about its findings. He is asked how aspirin compares with the top-selling cholesterol-lowering drugs called "statins," which include pravastatin (brand name: Pravachol), lovastatin (Mevacor), simvastatin (Zocor), fluvastatin (Lescol), and atorvastatin (Lipitor).

I'm pursuing the question of whether people on statin drugs can be just as safely, effectively, and less expensively treated with aspirin.

Dr. Pignone: What a great question. People who have had a heart attack will probably benefit from taking both drugs. As for people who have not had a heart attack or do not have heart disease, both statins and aspirin will reduce nonfatal heart attacks. The amount is about the same for both drugs: a 30% risk reduction.

Can you translate that?

Dr. Pignone: A 30% risk reduction means that if you have a 10% risk of having a heart attack over the next ten years, and you go on statin or aspirin therapy, your risk goes down to 7%. Another way of saying it is that aspirin or statins will reduce your risk of having a heart attack by a third. People can determine their risk for heart disease by going to our Web site at www.med-decisions.com. Our information is based on the Framingham Heart Study, which followed a large number of people over the course of many years to determine the risks of heart disease. [At our Web site] you can also see how taking aspirin or statins will affect your risk of having a heart attack.

What about reducing the heart attack death rate?

Dr. Pignone: [The studies show that] there's a trend for both drugs to reduce fatal heart attacks, but the people [in these studies] are generally in good health. Not many died [within the study period], so we do not have enough statistical certainty to reach a firm conclusion.

And the harms of statins?

Dr. Pignone: The harms of statins are pretty small. About one in 1,000 people will develop a serious amount of muscle damage. A few percent will have muscle pain; and less than one in 10,000 will have a serious consequence like kidney failure or death. We don't know how many of the serious adverse events occurred because of Baycol [a statin], which was withdrawn, but it appears to happen, rarely, with all the statins. Most of the serious adverse events occurred among persons who had underlying serious illness, or were on more than one cholesterol-lowering drug at the same time.

What about the other adverse reactions reported by people on statins like memory loss, insomnia, and fatigue?

Dr. Pignone: In randomized controlled trials, there appears to be no difference in the rate of these symptoms between people on statins and people on placebos. Putting all the statin trials together, we have information from over 30,000 people. The trials lasted five to seven years, and statins have been available for 10-15 years, so we are pretty certain that there are no major side effects beyond muscle damage. The cost, though, can also be considered an adverse effect. [Statins can cost up to $1,800 per year.]

And the risks of taking low-dose aspirin?

Dr. Pignone: If 1,000 middle-aged or older people take aspirin over five years, about one will have a bleeding stroke. And about five out of 1,000 will have bleeding in their GI tract that will require hospitalization.

Doses used in the trials ranged from 75 mg to 500 mg a day. Does bleeding occur even at the lowest dose?

Dr. Pignone: You can't avoid the bleeding side effects of aspirin by using a very low dose. Aspirin is very good at blocking our platelets, which is why it increases the risk of bleeding and also prevents heart attacks. So that's the data-similar benefit for reducing heart attacks and a little more adverse effects of aspirin, but a substantially lower cost. Currently, we don't know which drug is the better initial choice, but we plan to use cost-effectiveness modeling to examine this question further and help inform clinical practice.