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ASA Everyday | Will Aspirin Help or Harm You?

Will aspirin protect you from a heart attack? That seemingly simple question has become highly controversial. New research suggests healthy people over 70 won't benefit. What are the harms?

Americans have long been told that aspirin is “the wonder drug that works wonders.” Aspirin (acetylsalicylic acid or ASA for short) was supposed to prevent heart attacks and strokes caused by blood clots. In addition, a number of studies suggested that regular aspirin intake might reduce the risk of cancers of the colon, rectum, esophagus, stomach, breast, lungs, liver, pancreas and ovaries. Sounds wonderful. But prepare for a huge flip-flop. New studies published in the New England Journal of Medicine (Sept. 16, 2018) suggest that aspirin does not prevent heart attacks in older people. Those taking ASA actually had a higher death rate from cancer. Yikes! What the heck is going on?

Why People Started Taking Aspirin to Prevent Heart Attacks:

Let’s start at the beginning. The Physicians’ Health Study was one of the most impressive clinical trials of its day. Over 22,000 male doctors were recruited. Half were randomized to take one standard dose of aspirin (325 mg) every other day. The other half received a placebo pill. This double-blind trial is the best modern medicine has to offer.

After 57 months the investigators took the highly unusual step of terminating the study early. This was not because ASA had become a problem. To the contrary, the results were too favorable. The authors shared their data over 30 years ago in the New England Journal of Medicine (January 28, 1988):

“At a special meeting on December 18, 1987, the external Data Monitoring Board of the Physicians’ Health Study took the unusual step of recommending the early termination of the randomized aspirin component of the trial, primarily because a statistically extreme beneficial effect on nonfatal and fatal myocardial infarction had been found.”

“Overall, there was a 47 percent reduction in the risk of total myocardial infarction [heart attack], which is statistically significant. This includes significant benefits of ASA on both nonfatal and fatal events.”

In 1991 a follow-up analysis of the Physicians’ Health Study reported more good news about aspirin (Annals of Internal Medicine, May 15, 1991).  Doctors who had chest pain (stable angina) had a 70% reduction in heart attacks if they were taking aspirin:

“Our data indicated that alternate-day aspirin therapy greatly reduced the risk for first myocardial infarction among patients with chronic stable angina, a group of patients at high risk for cardiovascular death.”

A More Recent ASA Analysis:

Over the last three decades there has been a great deal of controversy about the value of aspirin for preventing heart attacks and other health problems.

An analysis of ASA benefits published in PLoS One (Nov. 30, 2016) concluded that increased use of aspirin by high-risk older Americans was warranted.  Their conclusion:

“As the US works to advance the triple aim of better care, better health, and smarter spending, ensuring patients receive effective preventive care will be critical. Given aspirin’s remarkable preventive effectiveness, it is a rare example of a technology that may produce less disease and better long-term health outcomes for Americans at a low price.”

New Contradictory Aspirin Research:

Three papers published in The New England Journal of Medicine (Sept. 16, 2018) present the results of a study of aspirin to prevent heart attacks in people over 70 . The study was called ASPREE (Aspirin in Reducing Events in the Elderly).

Here is what the researchers found:

“Of the 19,114 persons who were enrolled, 9525 were assigned to receive aspirin and 9589 to receive placebo. A total of 1052 deaths occurred during a median of 4.7 years of follow-up. The risk of death from any cause was 12.7 events per 1000 person-years in the aspirin group and 11.1 events per 1000 person-years in the placebo group. Cancer was the major contributor to the higher mortality in the aspirin group, accounting for 1.6 excess deaths per 1000 person-years. Cancer-related death occurred in 3.1% of the participants in the aspirin group and in 2.3% of those in the placebo group.”

The conclusions:

“Higher all-cause mortality was observed among apparently healthy older adults who received daily aspirin than among those who received placebo and was attributed primarily to cancer-related death. In the context of previous studies, this result was unexpected and should be interpreted with caution.”

Despite the caution expressed by the authors, headlines were emphatic about the disappointing results:

“Strike Three forAspirin in Primary Prevention” in Medscape, September 17, 2018

“Daily aspirin may be harmful for healthy, older adults, large study finds” by NBC News, September 16, 2018

“Study: A Daily Baby Aspirin Has No Benefit For Healthy Older People” in Health News from NPR, September 16, 2018

The Dangers of ASA:

One of the important findings of the ASPREE trial was the increased risk of bleeding (New England Journal of Medicine, Sept. 16, 2018).

“Conclusions: The use of low-dose aspirin as a primary prevention strategy in older adults resulted in a significantly higher risk of major hemorrhage and did not result in a significantly lower risk of cardiovascular disease than placebo.”

“The rate of major hemorrhage was 8.6 events per 1000 person-years in the aspirin group, as compared with 6.2 events per 1000 person-years in the placebo group.”

There were two major bleeding events: Bleeding within the upper gastrointestinal tract and bleeding within the brain.

The Bottom Line:

This ASPREE study produced no evidence that aspirin protects healthy older people (over 70) from cardiovascular complications. ASA did increase the risk for bleeding.

The People’s Pharmacy Perspective:

This was a primary prevention trial. In other words, it involved people who did not have heart disease. In that respect it was similar to The Physicians’ Health Study. The new results contradicted the earlier study. Both trials were randomized and placebo-controlled. In one, subjects took 325 mg of ASA every other day. In the ASPREE trial people over 70 took 100 mg aspirin every day.

People who already have heart disease and those who have been advised by their doctors to take aspirin should NOT stop until they have a chance to discuss aspirin use with their health care providers. There are people who are still expected to benefit from taking low-dose aspirin as a preventive measure.

We have no good answer to the question of ASA and cancer. There are a significant number of studies showing that aspirin may protect people against malignancy or reduce the risk of metastases once cancer is diagnosed. Here are some articles about this research:

How Good Is Aspirin Against Cancer in New Study?

Will Aspirin Keep Barrett’s from Turning into Cancer?

How Do You Weigh the Benefits and Risks of Aspirin?

The Bottom Line:

Healthy older people might experience more harm than benefit and should not take daily ASA on their own. People with heart disease or who are at high risk for a heart attack may benefit from aspirin. No one should embark on long-term aspirin treatment without a thoughtful conversation with a knowledgeable health professional.

Share your own thoughts about ASA in the comment section below.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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