Coronary artery calcium screening is probably cost-effective in men, but unlikely in women.
Introduction
In an ongoing effort to prevent cardiovascular disease (CVD), clinicians have to distinguish individuals who are very likely to get a heart attack or stroke in the future, from those who have a low risk of developing these diseases. Individuals at high risk can benefit from cardioprotective treatment such as statins and aspirin. Guidelines on prevention of CVD recommend traditional risk factors such as blood pressure and cholesterol levels to be used to predict someone’s future risk of CVD. These predictions are not perfect – they sometimes over- or underestimates an individual’s true risk of disease. Earlier research has shown that using the results of a CT scan which measures the amount of calcium in the coronary arteries, substantially improves these predictions. What was unknown before our study was whether the improved prediction –by screening individuals with CT, would lead to more lives saved against acceptable costs.
Methods
In order to address this question, we developed a computer-simulation model using data from the Rotterdam Study, a population based cohort study. We compared CT coronary calcium screening with a number of important alternatives - current practice as observed in the Rotterdam Study, full implementation of current CVD prevention guidelines and statin therapy for all individuals. Asymptomatic study participants were simulated over their remaining lifetime. We calculated the life expectancy of these individuals for all alternatives, taking into account their quality of life and lifetime costs. We focused on individuals at intermediate risk of coronary heart disease.
Results
We found that in men, CT coronary calcium screening increased the (quality adjusted) life expectancy compared to the other 3 strategies, but also cost more. In fact, screening men for coronary calcium with CT would cost about $50,000 per quality adjusted life year gained. In women things were different. Similarly to men, CT coronary calcium screening increased life expectancy and was more costly compared to current practice and statin therapy in women. However, fully implementing current CVD prevention guidelines was even more effective compared to CT coronary calcium screening in women, and only a little more expensive. Analysis of uncertainty revealed that there was considerable uncertainty about the value of CT screening in men. In women, results were more robust.
Conclusions
From our modeling study, we conclude that screening for coronary artery calcium with a CT scan in asymptomatic individuals at intermediate risk of CHD is probably cost-effective in men, but unlikely to be cost-effective in women.
