Aspirin: Risk vs. Benefit

Medicine is an enterprise that evolves over time. This is because new information comes to light and the synthesis of data takes time. Also, not surprisingly, much of what we do comes with the baggage of “that’s how we have always done it.” Change is incremental and often controversial.I have blogged in the past about the use of aspirin. This topic needs to be divided into those patients who have had a vascular event such as a stroke or myocardial infarction and those who are at risk and have not had an event. It is otherwise called primary and secondary prevention. Further, the groups need to be divided into male and female because the difference between them seems to be quite real but poorly understood.

If you have suffered stroke caused by a blood clot or a myocardial infarction, or have undergone coronary artery bypass grafting or angioplasty, then taking aspirin for life is generally recommended. It’s in the primary prevention group that the discussion is about.

This discussion dates back to 2002 when the US Preventive Services Task Force published its original study. This was updated in March of this year and states that aspirin is beneficial to men 45 to 79 in preventing myocardial infarction and preventing stroke in women aged 55-79. In 2003, the FDA advisory panel voted 11-3 to reject a petition by Bayer to expand aspirin’s indications to be used for primary prevention in moderate risk patients.

Since that time, papers have been published showing that in key patient populations such as those with asymptomatic atherosclerosis, type 2 diabetes and peripheral artery disease, no benefit over risk can be found. This was further propelled by the publication of an article by the group that started the whole debate the Antithrombotic Treatment Trialist group from Oxford, England. It was this group, in 2002, which published the original article. This group published again this March reversing their original opinion. I quote from their article, “We should be careful not to give the impression that aspirin doesn’t work. It works. But the balance of benefit / hazard is not good enough for a primary-prevention situation.”1

If you are taking low dose aspirin to “prevent” something and have never had an event then you should talk with your doctor. This is especially true of women who seem to be at the greatest risk and receive the least benefit. The risk of bleeding is real; the benefit seems more ephemeral.

1. Lancet 2009; 373:1849-1860.

Tags: aspirin, Myocardial Infarction, Stroke

This entry was posted on Friday, December 11th, 2009 at 2:44 pm and is filed under Coronary Artery Disease, Myocardial Infarction, Peripheral Artery Disease. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.