Individual and Population Benefits of Daily Aspirin Therapy: A Proposal for Personalizing National Guidelines

Background— Clinical practice guidelines that help clinicians and patients to understand the magnitude of expected individual risks and benefits would help with patient-centered decision-making and prioritization of care. We assessed the net benefit from taking daily aspirin to estimate the individual and public health implications of a more individualized decision-making approach. Methods and Results— We used data from the National Health and Nutrition Examination Survey representing all US persons aged 30 to 85 years with no history of myocardial infarction and applied a Markov model based on randomized evidence and published literature to estimate lifetime effects of aspirin treatment in quality-adjusted life years (QALYs). We found that treatment benefit varies greatly by an individual's cardiovascular disease (CVD) risk. Almost all adults have fewer major clinical events on aspirin, but for most, events prevented would be so rare that even a very small distaste for aspirin use would make treatment inappropriate. With minimal dislike of aspirin use (disutility, 0.005 QALY per year), only those with a 10-year cardiac event risk >6.1% would have a net benefit. A disutility of 0.01 QALY moves this benefit cut point to 10.6%. Multiple factors altered the absolute benefit of aspirin, but the strong relationship between CVD risk and magnitude of benefit was robust. Conclusions— The benefits of aspirin therapy depend substantially on an individual's risk of CVD and adverse treatment effects. Understanding who benefits from aspirin use and how much can help clinicians and patients to develop a more patient-centered approach to preventive therapy.