There is widespread agreement that the U.S. health care system faces unprecedented challenges. Overall life expectancy has improved, but racial and socioeconomic disparities in mortality and health status have recently been widening. Many Americans fail to receive treatments of proven benefit—a burden that falls most heavily on racial minorities and low-income populations. The safety and reliability of care in hospitals, surgical centers, nursing homes and physician offices is far from assured.

Most patients receive care from multiple different physicians who only rarely coordinate their care or ensure that their recommendations are clear, consistent and understood by patients and their families. Health care costs—already the highest in the world—are growing at a rate that poses a serious threat to patients, employers and the nation. And almost 50 million Americans lack health insurance.

In U.S. health care, it's not only who you are that matters; it's also where you live. As numerous studies and previous Dartmouth Atlas reports have documented, income and race are important determinants of both the health care patients receive and of patients' health care outcomes. These disparities are particularly striking when examined across U.S. states and regions. This Dartmouth Atlas Project Brief Report offers a window into both underlying causes and opportunities for reform by focusing on important measures that can be reliably determined from Medicare data. The major findings are as follows.

• The rate of leg amputation—a devastating complication of diabetes and peripheral vascular disease—is four times greater in blacks than in whites.
• For evidence-based services, such as screening mammography and appropriate testing for diabetes, disparities across states and regions are substantially greater than the differences by race.
• Regions differ dramatically in their use of the hospital as a site of care.

The findings highlight the importance of understanding health and health care within a local context—and of efforts to explore and address the underlying causes of disparities within and across regions.