It is not uncommon for me to see aspirin on the medication list of many of my older patients. It is most common with my well-controlled hypertensive or hyperlipidemia clients whom have no history of clinically evident cardiovascular (CV) disease. So when I ask them why they are on aspirin, the common reply is, “I read that it prevents heart attack and stroke so I started it on my own”, or “My husbands cardiologist suggested I take it after I took him in for a check up”. Two new studies in 2018 might shed some light on the subject.
In the ARRIVE trial, some 12,000 non-diabetic patients were randomized to 100mg of daily aspirin or placebo. Enrolled men were 55 years or older with 2 or more CV risk factors. Women in the study were at least 60 years old and had 3 or more CV risk factors. After a 5 year follow up aspirin had no CV benefit in reducing CV-related death, heart attack, unstable angina, stroke or transient ischemic events anymore than placebo. Those in the aspirin group had a slightly higher risk for gastrointestinal bleeding.
In the ASCEND trial, 15,000 middle aged or older diabetic patients were randomized to 100mg of aspirin daily or placebo. During average follow up of about 7 years, aspirin prevented 1 vascular event but caused 1 serious hemorrhage for every 100 treated patients.
So what does this mean…
Maybe we shouldn’t use aspirin as the magic prophylactic bullet for primary prevention that we once thought. Among diabetic patients, the trade off between a small benefit and harm are razor thin. And balancing one adverse event (CV event) against another adverse event (gastrointestinal bleed) is not straightforward. We cannot predict which of those outcomes would apply to any given patient. The other consideration is that a large proportion of patients in both studies were taking statins and antihypertensive drugs, and only a small proportion were current smokers. So you could conclude that these studies examined the incremental benefit of aspirin, added to other standard preventative treatments.
I like to individualize my healthcare with patients since outcomes in studies give us associations and not cause-and-effect results. One additional way to determine if a patient would benefit from aspirin is by performing a random urine test known as Aspirin Works. This measures 11-Dehydrothromboxane B2 in the urine which is produced from the breakdown of thromboxane A2. It is released by activated platelets (that cause our blood to clot) and urine levels can be used to monitor the response to aspirin therapy. This test may determine that you don’t need aspirin, or if on aspirin that your dose needs to be changed.
Ask your doctor or practitioner to perform this simple urine test to see if a daily aspirin would specifically benefit you.
Reference: Brett, A. Aspirin for primary prevention of cardiovascular events; JWatch.org, Oct 1, 2018, Vol. 38, No. 19.
NEJM JW Cardiol Oct 2018 and N Engl J Med 2018 Aug 26; [e-pub]
