In the 1960s, the potential of aspirin to prevent the formation of thrombosis (anti-platelet aggregation) was discovered. In 1985, the United States Food and Drug Administration (FDA) approved its indication for preventing second cardiovascular events in people who had already had a heart attack. Since then, its use for this purpose has been controversial and the recommendations have evolved, going from its effectiveness in primary prevention (when there has never been a cardiovascular event) in people at risk (hypertensive, diabetic, obese, hypercholesterolemic ) to the limitation of the indication for those who are already sick (secondary prevention).
The latest recommendations are from April, when the US Preventive Services Task Force (USPSTF) amended the 2016 guideline on the daily use and intake of low-dose aspirin to prevent cardiovascular disease (CVD). “Do not initiate the use of low-dose aspirin for the primary prevention of cardiovascular disease in adults 60 years of age and older,” was the recommendation. The latter guidelines stated that for people aged 40 to 59, who have at least a 10% risk of developing cardiovascular disease, the benefit is small, so the decision to take the drug should be made jointly between the doctor and the patient.
Four months later, a new nuance has arrived, in which women are placed at the center of prevention. Specifically, “Low-dose aspirin should be considered for primary prevention in women aged 40-59 years at high risk of atherosclerotic cardiovascular disease (ASCVD) and in those aged 60-69 years at cardiovascular risk of at least 20% or who have diabetes associated with a risk of ASCVD of 10%”, can we read in the article published in the scientific journal ‘Jama’ by doctors Mayo Clinic and Harvard University School of Medicine.
The results come from an analysis of 13 primary prevention clinical trials, which included 161,680 participants with no history of cardiovascular disease, 53% of whom were women. Aspirin doses below 100 mg have been evaluated in 11 trials, in which no significant reduction in mortality was observed. What was found was that taking the drug reduced the number of non-fatal heart attacks and strokes – the data for women came from a single study (from the “Women’s Health Study”, the first large-scale prevention study), which included 39,876 participants. The most negative part is that the examination confirmed an increased risk of bleeding – gastrointestinal bleeding, intracranial bleeding, even major bleeding requiring a transfusion – soon after starting aspirin for prevention, especially in men over 60 years old.
So, is it okay to take low-dose aspirin to prevent heart attacks in those who haven’t had it?
Here are the proposals from different medical organizations:
“US Preventive Services Task Force” (USPSTF), 2022: use of 100 mg may be considered in people aged 40 to 59 with a 10% risk of developing cardiovascular disease;
American Diabetes Association, 2022: Doses of 75-162 mg are considered in diabetics over 50 with an additional cardiovascular risk factor who are not at risk for bleeding.
European Society of Cardiology, 2021: Not recommended when cardiovascular risk is low because bleeding risk is higher. Under 70, and for people at very high cardiovascular risk, each particular situation must be assessed.