The American Heart Association recommends that individuals who have been told by their doctors that they are at a high risk for heart attack and heart attack survivors should take a low-dose aspirin every day. Aspirin thins the blood, helping to prevent heart attack or stroke resulting from a lack of blood supply.

Nearly 60 million Americans are estimated to be using daily aspirin therapy, but researchers at Duke University have discovered it may not be as effective as expected.  Given that people on low-dose aspirin daily still present with heart attacks and strokes, it was apparent that this therapy did not always work.  An estimated 25 to 30 percent eventually have a stroke or a heart attack.

The researchers recruited three groups of volunteers.  Two of these were healthy volunteers and one was made up of patients with heart disease being seen by outpatient cardiology practices.  The patients were already on low-dose aspirin therapy and one of the groups of health volunteers was given a daily standard strength aspirin.  For most participants, the body responded as expected to aspirin therapy.  However, for some, a genetic marker found in the individual’s RNA indicated that the person may not respond to this therapy and may be aspirin-resistant.  The researchers estimated that 10 to 15 percent of the general population has this marker, making aspirin therapy ineffective for them.

According to the Mayo Clinic, aspirin therapy is also not recommended for everyone.  Some individuals may also have an aspirin allergy, which could present as asthma caused by aspirin.  Also, some people with a bleeding or clotting disorder should not take on the additional risk of thinned blood.  Finally, for those that suffer from bleeding ulcers in the stomach, the thinned blood could also be life-threatening.

The identification of a potential biomarker for aspirin resistance is one of the latest developments in the field of pharmacogenomics.  This field studies how an individual’s genetic makeup affects his or her response to drugs.  There are a number of controllable factors, such as lifestyle, diet, and environment that may also influence the effectiveness of a drug, but genetics could help guide doctors on which therapies to select.  This field can reduce the need for trial-and-error with trying different medications.  Pharmacogenomics can also help develop more powerful medications, targeting areas that will be most effective genetically.  Finally, by decreasing issues with side effects and wasted, ineffective drugs, this may decrease overall healthcare costs.