‘rdan’ quotes a study in the New England Journal of Medicine.

Although some preventive measures do save money, the vast majority reviewed in the health economics literature do not. Careful analysis of the costs and benefits of specific interventions, rather than broad generalizations, is critical. Such analysis could identify not only cost-saving preventive measures but also preventive measures that deliver substantial health benefits relative to their net costs; this analysis could also identify treatments that are cost-saving or highly efficient (i.e., cost-effective).
In addition to determining which preventive measures and treatments are most efficient, it will be necessary to identify those that are not yet fully deployed and those that could serve a large population and bring about substantial aggregate improvements in health at an acceptable cost. Findings that some cost-saving or highly efficient measures are underused would indicate that current practice is inconsistent with the efficient delivery of health care. Other services might be identified as overused, and such findings would underscore the importance of fashioning policies that provide incentives to shift practice toward more cost-effective delivery of health care.

Some people want to believe that preventive medicine is the solution to rising health care costs. Instead, these authors recommend careful cost-benefit analysis of all forms of health care. I agree.