Preventing chronic disease: an important investment, but don't count on cost savings.

Over the four decades since cost-effectiveness analysis was first applied to health and medicine, hundreds of studies have shown that prevention usually adds to medical costs instead of reducing them. Medications for hypertension and elevated cholesterol, diet and exercise to prevent diabetes, and screening and early treatment for cancer all add more to medical costs than they save. Careful choices about frequency, groups to target, and component costs can increase the likelihood that interventions will be highly cost-effective or even cost-saving.