Comparative effectiveness studies of medications.

Comparative effectiveness studies of medications or, more appropriately, studies comparing the safety and efficacy of drugs have been conducted for decades, particularly for cancer chemotherapy. Research oncologists can stratify individuals participating in studies using prognostic criteria based on tissue diagnosis and disease staging. Conversely, research cardiologists, in particular those evaluating drugs for atherosclerotic vascular disease, have had to stratify individuals using criteria based on the risk of having a vascular event (ie, coronary heart disease risk). During the past 20 years, new imaging techniques, such as coronary calcium scoring, that are able to screen asymptomatic populations for atherosclerosis have been developed. In the future, studies comparing drugs for cardiovascular disease should be based on the presence of disease, such as atherosclerosis, rather than on the risk of a vascular event.