Aspirin for the primary prevention of cardiovascular disease in women: a cost-utility analysis

Overview

The role of aspirin in preventing cardiovascular disease, particularly heart attacks, has been most extensively studied in men. There are fewer studies looking specifically at women taking preventive aspirin. Available research shows that the beneficial effects of aspirin are different for women than for men. Aspirin, for example, prevents stroke in women and heart attacks in men. In this article, the authors create a mathematical model to help identify groups of women where aspirin use is cost-effective. They compared different groups of women with a focus on women of different ages. They found that aspirin is cost-effective in older women with risk factors for heart disease.

Methodology

The authors used a computer model to evaluate whether aspirin therapy reduced the risks of heart disease and stroke in women, compared with the increased harms of taking aspirin, including gastrointestinal bleeding and hemorrhagic stroke. They considered hypothetical populations of women with some risk factors for heart disease such as high cholesterol and high blood pressure. Using their model, they separately examined populations of women who were 55, 65 and 75 years old. The Framingham risk calculator estimated that the hypothetical 65-year-old women would have a 7.5% risk of developing heart disease and a 2.8% risk of stroke in the next ten years.

To compare the effects of these different diseases, they used quality-adjusted life years (QALYs) as the units of benefit or harm. QALYs are a measure of the ability to save lives and reduce the degree of disability among those living. Costs associated with aspirin use included such costs as the aspirin itself, physician visits for monitoring, care provided for aspirin complications, and care provided for heart disease and stroke events. The authors estimated:

  • The cost per QALY gained with aspirin use in their hypothetical populations of women

  • The harms and benefits of using aspirin in women of different ages.

Results

  • Aspirin use in a hypothetical population of 65-year-old women with moderate cardiovascular risk, produces net QALYs. In other words, aspirin reduced the risk of cardiovascular disease and stroke to a degree that outweighed the increased risk of GI bleeding and hemorrhagic stroke.

  • For this population of 65-year-old women, aspirin reduced cardiovascular risk at a reasonable cost of about $13,000 dollars per QALY.

  • In the models of 55-year-old women, aspirin was less effective than no treatment, meaning the harms outweighed the benefits.

  • At older ages (75 years), aspirin becomes less costly than no treatment, meaning that it both saves money and is beneficial to these women; a very favorable situation, as the benefit is achieved without additional costs.

Conclusions

  • Identification of groups of women where use of aspirin is cost effective. The authors created a mathematical model to help identify whether aspirin use is cost-effective in hypothetical populations of women. They emphasized that the benefits and harms of aspirin in women are age-dependent. Therefore, it is critical to consider patient age when making a recommendation regarding aspirin use.

  • Aspirin is cost-effective in older women with risk factors for heart disease. The model suggests that women over 65 years with moderate cardiovascular risk factors may benefit from aspirin use, despite the risks associated with it, and that this benefit is worth the associated added costs.