The headlines were grim. If you read no further you would conclude that aspirin is a bust when it comes to heart health.
Here is just a small sampling of the spin on the latest aspirin study:
“AHA: Aspirin Flops in Primary Prevention for Seniors,” Medpage Today
“Taking daily aspirin fails to prevent heart deaths,” Boston Globe
“Daily Aspirin May Not Prevent a First Heart Attack,” AARP News
“Large Japanese Trial Casts Further Doubt On Aspirin To Prevent A First Heart Attack,” Forbes
“New Study Downplays Aspirin’s Role in Preventing Heart Trouble,” ABC News
Before you quit taking your daily aspirin on the grounds that you might be incurring too big a risk, let’s dig a little deeper. Here at The People’s Pharmacy we try to provide the stories behind the health headlines and aspirin deserves that much.
The Details of the Japanese Study
- 14,464 Japanese volunteers (60-85 years of age) were randomized to take aspirin or no aspirin. These were people with risk factors for heart disease such as high blood pressure, high cholesterol, high LDL cholesterol, low HDL cholesterol, high triglycerides or elevated blood glucose.They were followed for an average of 5 years
- There was no significant difference in deaths between the two groups
- There was a significant difference in heart attacks. There were about half as many nonfatal heart attacks in the group taking aspirin compared to the non-aspirin group.
- There was also a significant difference in something called TIAs (transient ischemic attacks or pre-strokes). The aspirin group had 43 percent fewer TIAs than the non-aspirin group.
Why the Negative Spin?
You might wonder why the headlines and the accompanying articles were so negative when there was actually a pretty substantial benefit to taking aspirin. Had this been a statin-type drug there would have been huge headlines praising the power of the medication to reduce the risk of heart attacks and pre-stroke events by roughly 50 percent.
In fact, the very week that the aspirin study was in the news and getting such a negative spin by media doctors, they were praising the “dramatic” benefits of the drug ezetimibe (found in Zetia and Vytorin).
In a study presented at the American Heart Association, investigators reported that adding Zetia to simvastatin lowered the risk of heart attacks, strokes and other heart problems by 6.4 percent. There was no improvement in survival, however. In other words, those taking the combination of Zetia and simvastatin did not survive longer than those on simvastatin alone.
One physician from the Massachusetts General Hospital was quoted in the New York Times as saying:
“Fantastic…A truly spectacular result for patients.”
So, let’s try to make sense of this craziness. Aspirin was found in a large Japanese trial to reduce the risk of heart attacks by about 50 percent and we are told that aspirin is a “failure.” Zetia reduces the risk of heart attacks by 6.4 percent when added to simvastatin and we are told the results are “spectacular.” Go figure.
A cynical person might conclude that aspirin gets no respect because it is available over the counter and is incredibly inexpensive at pennies per day. Ezetimibe is a prescription drug and costs about $250 for a month’s supply.
Flaws with the Japanese research
Not mentioned in most of the news stories about aspirin are some fundamental problems with the Japanese study:
- This was not a double-blind trial. Patients knew whether they were getting aspirin or placebo. If this were a prescription drug trial, health experts would perceive this a major flaw in the study design.
- Many patients taking aspirin tended to stop taking aspirin over the length of the study. By the last year of the trial only 76 percent of the aspirin group was still taking the drug. Conversely, 10 percent of the people who were not supposed to be taking aspirin were actually doing so by the fifth year of the study.
- The investigators badly miscalculated the number of fatal heart attacks and other deadly vascular events in this group of Japanese subjects. They stopped the study early because there were so few heart attacks and strokes:
“…a pre-planned review at the first annual general examination in July 2006 showed that the incidence of primary outcome events (14 events among 6,745 enrolled patients) was much lower than originally estimated.”
That trend continued. At the end of the study involving 14,464 people only 56 had died in the aspirin group and only 56 had died in the non-aspirin group. The authors admitted that:
“…there remains a possibility that the statistically nonsignificnat reduction in the risk of death from cardiovascular causes, nonfatal stroke, and nonfatal myocardial infarction was due to the study being inadequately powered, rather than an absence of beneficial effect of aspirin.”
In other words, the Japanese participants were living longer and healthier lives regardless of whether they were taking aspirin or not. This screwed up the statistics.
There is a peculiarity of the Japanese population that was missed by other media outlets. The authors acknowledge:
“Hemorrhagic stroke is more common in Japanese populations than in Western populations.”
One hypothesis for this anomaly is that people in Japan have lower cholesterol levels than people in the U.S. and this increases their risk for bleeding strokes. Regardless of the cause of this vulnerability, the aspirin takers in this trial had a higher risk of bleeding strokes than non-aspirin takers. Unusual susceptibility may have made the Japanese subjects more vulnerable to such events compared to westerners.
The Bottom Line:
Many other studies have demonstrated that aspirin does indeed reduce the risk of first heart attacks, “cardiovascular events” and deaths. This is called primary prevention. An editorial in the JAMA that accompanied the Japanese study noted that in primary prevention trials involving over 100,000 participants, aspirin demonstrated a 12 percent reduction in “major vascular events.”
Everyone agrees that aspirin plays a valuable role in secondary prevention. That is, it helps prevent a repeat heart attack in patients who have already had their first event. It is also well established for people who have a clear diagnosis of heart disease.
The editorial in the JAMA noted that:
“In pooled data from about 200 trials among patients with known vascular disease, aspirin was shown to have long-term benefits in preventing major vascular events.”
In addition, the authors of this study specifically point out that aspirin has an anti-cancer effect:
“There is also a growing body of evidence to suggest benefits for aspirin in the prevention of colorectal and other cancers, and the prevention of cancer recurrence, including in the Japanese population.”
No one should ever embark on long-term aspirin treatment without medical supervision. Aspirin can cause potentially life-threatening bleeding. It also may interact with a number of prescription medications. But aspirin should not be written off as a failure because of misinterpretation of the data by the media. We hope this in-depth analysis has provided helpful insights.
