health disparities. This is a broad topic (see for example, Chapter 11, this volume), and so we will organize our contribution along five basic points.
(1) There is considerable variation in the utilization of health care, and in outcomes, by region.
The phenomenon of “small area variation” in utilization rates has been studied for a number of decades. Most recently the Dartmouth Atlas of Health Care has used nearly 100 percent samples of Medicare enrollees to measure such differences across 306 Hospital Referral Regions (HRRs) in the United States (Wennberg and Cooper, 1999). Even after controlling for differences in underlying health status across regions, there is clear evidence of persistent and large differences in treatment patterns, even in contiguous areas. Much of the current debate is how to interpret such differences—are they “demand” driven by patient preferences, or “supply” driven by physician beliefs and historical patterns of hospital location? In addition to disparities in treatment patterns, there are also substantial variations in health outcomes by region. Recent research has documented race-specific and gender-specific variations at the county or state level in overall mortality rates as well as disease-specific mortality rates (Barnett et al., 2001; Casper et al., 2001).2
(2) People who are African American or Hispanic or belong to other minority groups tend to seek care from different hospitals and from different physicians compared to non-Hispanic whites.
It is not surprising that African-American and Hispanic patients tend to see different physicians and are admitted to different hospitals compared to non-Hispanic whites. This is largely the consequence of where people live: there are far fewer African Americans seeking care in eastern Tennessee hospitals than in Mississippi hospitals, and many more Hispanic patients seeking care in hospitals in Florida, Texas, and California than in Maine and New Hampshire. Furthermore, patients of color who live in the same neighborhood as whites may go to different hospitals or (more clearly) see different physicians and in different settings for a variety of reasons, including financial barriers, as well as racial barriers to care (Lillie-Blanton, Martinez, and Salganicoff, 2001). Patients also tend to be seen by physicians of the same race, although one study (Harrison and Thurston, 2001) suggested this matching is in part the consequence of minority physicians being more likely to live near minority neighborhoods.
(3) Racial disparities are pronounced in some areas, but are less so (or may not be present) in other areas.