Aspirin and Heart Attacks: Secondary Prevention, Yes; Primary Prevention, No

We discussed in the April issue of Worst Pills, Best Pills News that there is a great deal of difference between the use of the cholesterol-lowering “statin” drugs, such as atorvastatin (LIPITOR) or rosuvastatin (CRESTOR) for preventing heart attacks or strokes in people who have not had a previous cardiovascular event, including angina, strokes, or heart attacks (primary prevention) — and their use for people who have already had such cardiovascular events (secondary prevention). There is much less evidence for their effectiveness in primary prevention, especially in people with fewer risk factors such as high blood pressure, smoking, or diabetes. In these latter cases, it is likely that the risks outweigh the benefits.

The same appears to be the case for the use of aspirin in primary prevention of heart attacks. Aspirin is the preferred preventive treatment for those who have already had a heart attack (secondary prevention), at least for the majority of people who are not intolerant to aspirin. The Food and Drug Administration (FDA) has approved the use of aspirin in the following situations in patients:

• who have had a previous heart attack or unstable chest pain (angina), to reduce death and non-fatal heart attacks
• who have chronic stable angina, to reduce heart attacks and sudden death
• who have undergone revascularization procedures, such as the placement of a stent, for a pre-existing condition
• who have had a suspected acute heart attack, to reduce vascular deaths
• who have had ischemic stroke or transient ischemia of the brain due to fibrin platelet emboli (clots), to reduce death and non-fatal stroke

In 2003, Bayer, the producer of Genuine Bayer Aspirin, petitioned the FDA to allow the use of aspirin to reduce the risk of a first heart attack in patients with a coronary heart disease risk of 10 percent or greater over 10 years.

On December 8, 2003, the FDA’s Cardio-Renal Drugs Advisory Committee met to evaluate the results of five published clinical trails submitted by Bayer to support their petition. The committee refused to recommend aspirin for primary prevention. Some of the concerns raised by the committee or by FDA staff included:

• In only one of the five studies submitted by Bayer was there a reduction in fatal heart attacks. In this study there was a larger, though not statistically significant, increase in fatal sudden death, strokes or other fatal cardiovascular events.
• “The lack of efficacy [prevention of cardiovascular events, primarily a first heart attack] in the face of associated morbidity, ie., bleeding, prevents the recommendation of use of aspirin for the primary prevention of cardiovascular morbidity and mortality.”

In response to the main question asked by of the advisory committee, should the professional labeling for aspirin recommend its use for primary prevention of heart attacks, the committee voted 11 to 3 against that recommendation

What You Can Do

The lack of evidence of an aspirin benefit in the primary prevention of heart attack is clearly outweighed by the increased risk of bleeding from aspirin, and you should not use aspirin for the primary prevention of heart attacks.