Aspirin - Unraveling the Truth About Aspirin for Heart Disease.

By Ryan Minarik, ND, LAc

 

Aspirin use for the prevention of heart attacks is heavily promoted through magazines and commercials by cardiologists   Yet, in my reading through medical literature, I frequently come across headlines and quotes that seem to indicate it had little, if any, true benefit for heart attack prevention. 

 

Aspirin is the drug name for salicylic acid, a derivative of white willow bark, which has long been used as an effective pain reliever and fever reducer.  White willow bark’s effectiveness in herbal preparations led to the development of a patentable drug form, and thus, aspirin. 

 

In the late 60’s, it was proposed that aspirin might reduce the stickiness of platelets, reducing clot formation.  If this were true, aspirin could help prevent heart attacks and strokes from clots.  Without going into needless details, early studies reported in the British Medical Journal and The Lancet, both prominent medical publications, indicated aspirin had no benefit in preventing or reducing second heart attacks in those who already had a previous attack.  More studies were done, but the conclusions were basically the same:  aspirin did little, if anything to prevent deaths from heart attacks.

 

A large study published in 1989, the Physicians Health Study (PHS), involved 22,000 doctors1.  Half the doctors received 325mg aspirin (in the form of Bufferin, we’ll get to that later), and the other half received a placebo.  The astounding results showed a 44% reduction in the risk of myocardial infarction (heart attack) in those who took aspirin.  This of course made national news, and the study’s website still touts it highly today.  A few key points, less highly touted:  the risk of death from cardiovascular events was unchanged (in study terms, no reduction in mortality).  With aspirin there was an increase in risk of ulcer and blood transfusion.  There also was a mild increase in stroke.  Finally, the benefit of reduced incidence of non-fatal heart attacks was primarily in individuals over 50 years old, and was greatest in those with lower cholesterol levels.  The higher the cholesterol, the less benefit.  Interesting.

 

Around the same time, a smaller, similar study was done with British doctors2.  This study had contradictory findings to the PHS: there was no statistically significant decrease in heart attack incidence, non-fatal or fatal, in those who took aspirin.  One argument is that the American study was much larger, and thus more relevant.  Maybe true, but 44% compared to 0% is a huge difference. 

 

Before going on to more recent studies, let me highlight a possibly minor but relevant difference in these studies:  the British study used pure aspirin, while the American one used aspirin in the form of Bufferin.  Why is that important?  Bufferin is aspirin, buffered with magnesium (one source has 97mg of magnesium per 325mg of aspirin3), a well-studied mineral with all the actions to prevent heart disease such as being a vasodilator, anticoagulant or clot-reducer, and antiarrythmic.  It also is a general muscle relaxant and helps with anxiety, key factors in long term heart disease risk.

 

Are you starting to get it?  Let’s move on...

 

Many short and long term studies were done in the 80s and 90s, and the benefits of aspirin were debated, but one fact remained true:  the incidence of fatal heart events did not change with aspirin.  In most studies, there seemed to be a reduction in the risk of non-fatal heart attacks, but only in those who were already at high risk for cardiovascular disease.  For those at low risk, a review of three major studies4 advised against prophylactic or preventative aspirin at all. In fact one of the three, the Nurses Health Study, found an increase in deaths.

 

In  2002, a group did a meta-analysis (a large scale review of past studies) on the benefits of aspirin to try to get some clarity.  This review confirmed that aspirin did not prevent or reduce deaths, and for those at low risk of heart disease, aspirin is definitely not indicated.  It did however, (and this is what is repeatedly highlighted in the media and by cardiologists) show that aspirin reduced the incidence of non-fatal heart attacks in high risk individuals.  But by how much?  The findings can often be worded to be misleading:  there was definitely a reduced risk, but the absolute difference in numbers having a heart attack was about 3.5% (36 more attacks per 1000 people not taking aspirin).  And remember, this is in a high risk population (previous heart attack, smoking, obesity, high blood pressure, etc), and there was still no difference in the number that actually died from these events. 

 

Aspirin is a well-known pain reliever, right?  So if there is no change in deaths, but the number of heart attacks is reduced, is aspirin just covering the often tell-tale heart pain that sometimes indicates an attack?  “Silent” myocardial infarctions, or those with no pain, are estimated to account for 25% of all attacks, so are these just increased?5,6  (By the way, I did not come up with that, it was proposed by a British doctor, John Cleveland, in his response to the above meta-analysis, whereby he highlights flaws even in that study and argues against aspirin use at all in heart disease)7 in 8

 

Most recently, a 2008 study highlighted in US World News and Report9 found a “contradiction” to earlier studies:  aspirin does not reduce heart attack or stroke risk (non-fatal or fatal) in people with diabetes or peripheral vascular disease, two populations for whom it was highly recommended.  It’s funny; if you truly review the studies, I don’t think this was very contradictory.

 

In summary,  it appears that aspirin may help reduce heart attack occurrence (but not death) only in individuals with high risk of heart disease that have had a heart attack before and are over 50 but have low cholesterol.  Prophylactic aspirin use undoubtedly increases risk of ulcer, kidney failure, and hemorrhagic stroke.  But if you’re still waiting for a more conclusive analysis, and want more than a 3% absolute reduction of potentially hiding the heart pain, consider this:  A recent study found cat owners had 30-40% less incidence of fatal (yes, even fatal) heart attacks!10  You’d think they’d spend more time analyzing that but I guess the Humane Society has limited resources.

 

If your doctor has prescribed aspirin, I am not suggesting to go off it immediately.  Truly, cardiologists can be lifesavers; they are invaluable specialists.  There are certainly some instances where aspirin is indicated and helpful, just ask why you’re on it, and maybe challenge the idea.  And if they can’t help, please see someone who will listen: get advice about proper amounts of magnesium, heart protective nutrients, foods, and herbs that can truly reduce clot risk, and dietary changes necessary to prevent heart attacks.

 

And until then... go hug a cat.

 

A couple good additional articles:

- Alternatives to aspirin for prevention of heart attack and stroke - Letter to the Editor

Townsend Letter for Doctors and Patients ,  May, 2002.  (Accessed at http://findarticles.com/p/articles/mi_m0ISW/is_2002_May/ai_85131534/?tag=content;col1)

 

- http://articles.mercola.com/sites/articles/archive/2002/01/26/aspirin-heart-part-one.aspx

 

References

1 Original Study Physicians Health Study: N Engl J Med. 1989 Jul 20;321(3):129-35.Links

 

2 British Doctors Study: Peto R; Gray R; Collins R et al. Randomised trial of prophylactic daily aspirin in British male doctors. BMJ 1988 Jan 30 296 313-316.

 

3 I found magnesium in the ingredient list, but couldn’t find actual magnesium amounts in American drug company websites. However, a Canadian pharmacy reported: ACETYLSALICYLIC ACID 325 MG, DIHYDROXYALUMINUM AMINOACETATE 49 MG, MAGNESIUM CARBONATE 97 MG  (http://www.77canadapharmacy.com/Bufferin.php)

 

4 John M. Boltri, Mark R. Akerson, Robert L. Vogel .  Aspirin prophylaxis in patients at low risk for cardiovascular disease: a systematic review of all-cause mortality - Original Research.  Journal of Family Practice,  August, 2002.

 

5 Cleland JGF, Bulpitt CJ, Falk RH, Findlay IN, Oakley CM, Murray G, et al. Is aspirin safe for patients with heart failure? Br Heart J 1995; 74: 215-219[Medline].

 

6 Cleland JGF. Anticoagulant and antiplatelet therapy in heart failure. Curr Opinion Cardiol 1997; 12: 276-287 [Medline].

 

7 For Debate:  Preventing atherosclerotic events with aspirin.  BMJ. 2002 January 12; 324(7329): 103–105.

 

8 http://articles.mercola.com/sites/articles/archive/2002/01/26/aspirin-heart-part-one.aspx  accessed 5/12/09

 

9 http://health.usnews.com/articles/health/healthday/2008/10/17/aspirin-doesnt-prevent-first-heart-attack-stroke_print.htm  accessed 5/12/09

 

10 Qureshi A et al, "Cats as domestic pets reduce the risk of cardiovascular diseases: Results from the Second National Health and Nutrition Examination Study Mortality Follow-up Study." ASA Meeting 2008.