Researchers have revealed crucial insights into the comparative effectiveness and safety of different aspirin dosages for secondary prevention of atherosclerotic cardiovascular disease. 

In the randomized ADAPTABLE trial, published in JAMA Cardiology, the researchers recruited 15,076 patients with a median age of 67.6 years—10,352 of whom were male and 4,724 of whom were female. The patients were then randomly assigned to receive either 81 mg or 325 mg of aspirin daily. The study aimed to assess the primary efficacy outcomes of all-cause mortality and hospitalization for myocardial infarction or stroke, and the primary safety outcome of hospitalization for major bleeding requiring transfusion. 

The researchers found no statistically significant sex-specific differences in outcomes between 81-mg and 325-mg aspirin doses, indicating similar safety and efficacy for both doses among patients with chronic, stable atherosclerotic cardiovascular disease.

Among the efficacy outcomes were:

• The primary efficacy outcome was similar among both sexes: 8.1% in female patients vs 7.1% in male patients.
• There was no significant interaction by sex for the primary efficacy endpoint between the two doses.
• Compared with male patients, female patients had a higher risk of hospitalization for stroke (adjusted hazard ratio [HR] = 1.72) but a lower rate of revascularization procedures (adjusted HR = 0.79) compared.

The safety outcomes revealed that:

• The rate of major bleeding was low, with no statistically significant differences between male and female patients.
• Female patients on the 81-mg dose had a slightly higher rate of bleeding compared with those on the 325-mg dose (adjusted HR = 2.21); however, this did not significantly impact overall safety.

Additionally, adherence to the randomized aspirin dose was similar between sexes. The patients in the 325-mg group were more likely to switch or discontinue their dose compared with those in the 81-mg group.

The trial's secondary analysis indicated no statistically significant sex-specific differences in the safety and efficacy of 81-mg vs 325-mg aspirin doses for the secondary prevention of atherosclerotic cardiovascular disease. Although the findings suggested that both doses may be comparable in safety and efficacy among both male and female patients, individual risk factors such as stroke and revascularization needs should be considered when tailoring aspirin therapy.

The results supported the continued use of aspirin as a cornerstone therapy in atherosclerotic cardiovascular disease management, with careful consideration of dose adjustments based on patient-specific factors.

For full conflict of interest disclosures, refer to the study.