Is the message about aspirin confusing patients?

Media reports and practice guidelines about aspirin use are inconsistent.

Last month we celebrated the 110th anniversary of aspirin. Aspirin was originally developed in 1897 for arthritis but that initial indication has expanded through years of clinical research. Physicians have placed more than 25 million Americans on aspirin therapy to prevent myocardial infarction. The drug’s cardiovascular beneficial effects are widely accepted in the medical community and beyond.

Despite these advances, surveys document that aspirin is still not being used by many who could benefit from it. So why isn’t it used more frequently?

Mixed messages

There are a number of possible reasons. The first of these concerns discrepancies in media reports that may contribute to an inconsistent message about its cardiovascular benefits. An article published online April 3, 2007, in The Wall Street Journal questioned whether women should take aspirin to prevent heart disease. The article was based on published studies with conflicting results, including the Women’s Health Study (WHS) and the Nurses Health Study.

Carl J. Pepine

Five days after the Journal article, an article appeared in The New York Times that recommended select age groups should consider taking aspirin. In that article, Elizabeth Nabel, MD, director of the National Heart, Lung, and Blood Institute, recommended that “men 45 and older and women over age 65 should take an aspirin every day to prevent heart attacks and strokes. Those at high risk should take up to 325 mg daily; all other men and women over 65 but at lower risk should consider 81 mg a day or 100 mg every other day.”

Secondly, aspirin is an over-the-counter medication that may be dangerous if administered during a viral syndrome to a person younger than 19 years, due to a statistical link with Reye’s Syndrome.

Third, the fact that aspirin use for fever or arthritis is often overshadowed by other NSAIDs may have muddied the waters for some about whether to take aspirin for cardiovascular prevention. Commercials for more popular lipid- and BP-lowering agents are commonplace on television; aspirin is not as widely publicized.

When the public is subjected to differing opinions and recommendations in the media, what are people to believe? We have no specific test for either physicians or patients to rely on that result in a recommendation for its use. Likewise, we lack a specific test to identify who will respond to its use. Finally, its benefits may be so intuitive that we simply assume that patients are taking it.

Aspirin proven beneficial

There is a well-documented reduction in risk for CHD and stroke for men aged 45 and older and women aged 65 and older who take aspirin. Ridker et al reported in 2005 that low-dose aspirin resulted in a 17% risk reduction for first stroke and a 24% reduction in ischemic stroke among apparently healthy women 45 and older. Aspirin use did not result in an increase of gastrointestinal illness or fatal bleeding events. Even more important, hemorrhagic stroke did not differ significantly between placebo and aspirin groups. Does the benefit of aspirin uniquely begin when one turns 45? Do 44-year-old men not achieve benefit?

The recent meta-analysis (Bartolucci and Howard) of six trials (British Doctors’ Trial [BDT], Physicians’ Health Study [PHS], Thrombosis Prevention Trial [TPT], Hypertension Optimal Treatment [HOT] study, Primary Prevention Project [PPP], and the WHS) assessing aspirin use in primary prevention of cardiovascular events suggested superiority of aspirin for total CHD (OR=0.772; P=.001), nonfatal MI (OR=0.755; P=.001), and total cardiovascular events (OR=0.852; P=.001) in 47,293 patients receiving aspirin and 45,580 not receiving aspirin.

Inconsistent recommendations

Review of the guidelines from American Heart Association/American College of Cardiology, AHA/American Stroke Association, American Diabetes Association, American Society of Health System Pharmacists, American Academy of Family Physicians, ACC/AHA/European Society of Cardiology, American College of Clinical Pharmacy, and the U.S. Preventive Services Task Force finds guideline language is inconsistent and potentially confusing.

The following statements are some examples: “start,” “continue indefinitely,” “can be continued,” “start and continue,” “administer,” “should be used,” “recommended,” “should be used concurrently,” “suggested,” “reasonable,” “acceptable options,” and “may be considered.” The language is highly variable. We need to be careful that we don’t send inconsistent messages to practioners or the public in our guidelines.

Another factor contributing to the confusion about aspirin is the dosage. Dosage recommendations are widely variable. Trial researchers have chosen between 75 mg (not available in the United States) and more than 650 mg, creating confusion when trying to pinpoint the appropriate regimen.

Most agree that lower doses cause less gastrointestinal side effects and have little difference in beneficial effect compared with higher doses. Rather than getting hung up on the dose perhaps our recommendations should simply be to take a pill as suggested by Gus Grant, MD, PhD, in a personal communication.

Just why professionals don’t recommend aspirin is unclear to me. No one owns aspirin or sponsors it – it’s available over-the-counter.

When I lecture, I often query the audience to see who takes aspirin. Virtually everyone raises their hands. Then I ask them if they recommend aspirin to their patients and about 80% raise their hands. Very few raise their hands when I ask if they recommend it to the general public for primary prevention.

As aspirin turns 110-years-old, perhaps it’s time we start using it to its full potential.

Carl J. Pepine, MD, is the Chief Medical Editor of Cardiology Today.

For more information:

• Bartolucci AA, Howard G. Meta-analysis of data from the six primary prevention trials of cardiovascular events using aspirin. Am J Cardiol. 2006;98:746-750.
• Ridker PM, Cook NR, Lee IM, et al. A randomized trial of low-dose aspirin in the primary prevention of cardiovascular disease in women. N Engl J Med. 2005;352:1293-1304.