AHA Scientific Sessions 2026 Abstract · Nov 2, 2026
Assessing Net Clinical Benefit of Primary Prevention Aspirin Therapy in Older Adults According to Coronary Artery Calcium Burden: The Multi-Ethnic Study of Atherosclerosis
By Razavi A, Dzaye O, Post WS et al.
Background: Among many individuals with a high burden of atherosclerosis, there is a net benefit from primary prevention aspirin therapy. Older adults have the highest coronary artery calcium (CAC) burden, but the role of aspirin therapy in older persons is less clear due to a concomitantly higher risk of bleeding. Research Question: Do adults > 70 years old with moderate to severely elevated CAC have net benefit from aspirin therapy for the primary prevention of atherosclerotic cardiovascular disease (ASCVD)? Methods: There were 832 Multi-Ethnic Study of Atherosclerosis (MESA) > 70 years old without known ASCVD or high-risk bleeding conditions at Visit 1 (2000-02). High-risk bleeding conditions were defined as systolic blood pressure > 160 mmHg, use of proton pump inhibitors or H2-blockers, or chronic kidney disease > stage 3b. Estimates for ASCVD risk reduction (11%) and increase in major bleeding (43%) with aspirin were derived from the ASPREE (ASPirin in Reducing Events in the Elderly) trial and applied to the five-year incidence of ASCVD and major bleeding events in MESA to calculate five-year number needed to treat (NNT ₅ ) and number needed to harm (NNH ₅ ). Analyses were stratified according to CAC burden (0, 1-99, > 100, > 300 Agatston Units [AU]) and age. Results: The mean age was 75 years, 50% were women, 63% were non-White, and 18% reported statin use. Three in four individuals had prevalent CAC, with 26% and 14% having CAC scores > 100 and > 300, respectively. The 5-year event rate per 100 person-years was 11.5 for ASCVD and 4.5 for major bleeding in the overall sample. There was a stepwise lower modeled NNT ₅ across higher CAC burden ( Figure ). Among these participants > 70 years old, the NNT ₅ was lower than the NNH ₅ for individuals with CAC > 300 (85 versus 97), but not for individuals with CAC > 100 (112 versus 97). Among those with CAC > 300, modeled benefit was greater for persons <80 years old (NNT ₅ : 90 versus NNH ₅ : 118) compared to those > 80 years old (NNT ₅ : 64 versus NNH ₅ : 35). Conclusion: Overall, older individuals with CAC <300 had net harm from aspirin. Among adults with CAC > 300, only those 70-79 years old had a net benefit from primary prevention aspirin therapy. Assessment of subclinical atherosclerosis burden in older adults may guide shared decision-making and treatment personalization when considering aspirin for primary prevention.