There are huge differences in health care spending across the United States. For example, age, sex and race adjusted spending for traditional (fee-for-service) Medicare in the Miami region was $8,414 in 1996, compared to the $3,431 spent in the Minneapolis region. The greater than twofold differences observed across U.S. regions are not due to differences in the prices of medical services or to differences in average levels of illness or socioeconomic status across regions. Rather, they are driven primarily by differences in the aggregate amount of medical services provided to apparently similar populations.

Because many specific treatments are known to be beneficial, such as emergency treatment of heart attacks, or surgery to replace a failing hip joint, most Americans assume that more medical care in general must also be beneficial.

Our current research, however, reveals that those who reside in high cost communities are no more likely to receive specific treatments of proven benefit or discretionary procedures that are likely to improve their function. Spending more, within the range observed in the US, results in greater use of "supply-sensitive" services: more frequent physician and specialist visits, greater use of diagnostic tests and minor procedures, and more frequent use of the hospital as a site of care.

We now have good reason to believe that those who receive more "supply-sensitive" care have no improvement in survival and are unlikely to have better quality of life. The potential mechanisms whereby more medical care may lead to harms that counterbalance any benefits are summarized in our recent article "Avoiding the Unintended Consequences of Growth in Medical Care: How might more be worse?"