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Tracking Trends in Health Care with GIS

Closing Community Hospitals

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Figure 1: Community hospitals that are 35 miles or farther from another hospital.

Rural hospitals provide access to hospital and other health services for millions of people. The map in Figure 1 was used to illustrate how possible hospital closures in rural areas could affect local communities. Counties designated as rural by the Census Bureau were selected so that all the hospitals located in rural counties could be identified. To this subset of all hospitals, another hospital subset--hospitals that were 35 miles or further from another hospital--was added.

ArcView Network Analyst was used to create drive distances around the hospitals and select hospitals that were not within 35 road miles of another hospital. The rationale behind selecting this subset of hospitals relates to the hospital service areas. Thirty-five miles is a reasonable distance to travel for essential health services, such as primary care and well child visits. In addition, a distance greater than 35 miles would make travel to a hospital in emergency situations difficult. The number of people that could be affected by the possible closure of a community hospital was calculated by adding the population figures for each county containing a community hospital. This analysis determined that approximately 17 million people could be affected by the closure of their local community hospital.

Health Professional Shortage Areas in Major Cities

Although hundreds of rural areas lack an adequate number of health care professionals to serve the primary care needs of the local population, areas located in the middle of large population centers also lack health professionals. These areas are designated Health Professions Shortage Areas (HPSA) by the Bureau of Primary Health Care at the Health Resources and Services Administration (HRSA). HPSAs can be designated for primary health care, mental health services, and dental services. The TrendWatch report focused on HPSAs with a shortage of primary care providers. HPSAs can be located within major cities and near major hospitals and clinics.

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Figure 2: Detroit area showing federal primary care HPSAs and community hospitals.

Figure 2 shows the primary care HPSAs located in the City of Detroit. HPSAs were selected by census tract using information provided on the HRSA Web site. Using this set of census tracts, the number of people living within the Detroit HPSAs was calculated as approximately 500,000 persons. Census data was also used to determine that approximately 30 percent of these people have incomes that fall at or below the poverty level. The map in Figure 2 highlights the relationship between hospitals and HPSAs in Detroit. In particular, it is interesting to note the small cluster of downtown hospitals are located on the edge of a large primary care HPSA. This map prompted questions regarding the types of services those five downtown hospitals were providing and whether or not they should be providing more primary care services, especially since they provide a large portion of the care to the uninsured population (as illustrated by the map in Figure 3).

Serving the Uninsured and Poor in Different Ways

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Figure 3: The Detroit area distributes indigent care among a larger group of hospitals.

America's safety net is often thought of as one big network of similar providers with common patient populations and funding streams. However, the provision of essential access services is a community-based issue. Uninsured populations vary from place to place and their needs differ accordingly. For example, communities that reside on the U.S.-Mexico border serve a large Hispanic immigrant population, many of whom are undocumented. The health needs of this community differ greatly from the needs of the uninsured in San Francisco, which has a large Asian community. These communities have designed and implemented very different methods of providing for the needy in their communities. The maps in Figures 3 and 4 highlight how different communities serve the uninsured and poor in very different ways. Some serve these populations with public hospitals and health systems bearing the primary responsibility and others spread care of the poor among many area hospitals.

These maps were created using AHA Annual Hospital Survey data. Using financial data from this survey, hospitals that together provide 70 percent of the Medicaid and uncompensated care in a given area were identified. As the map in Figure 3 shows, none of Detroit's 44 hospitals are public hospitals. In this area, 13 hospitals combine to provide care for the uninsured. In contrast, Houston, shown in Figure 4, has 51 hospitals. The only public hospital in the area provides 36 percent of the area's Medicaid and uncompensated care. In addition, five hospitals combine to provide 70 percent of care to the uninsured.

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Figure 4: Houston is an example of an area that relies on a public hospital.

In Detroit, hospitals can spread out the financial burden of serving the uninsured among a greater number of institutions and uninsured patients may not need to travel as far to receive care because hospitals providing charity care are located in geographically diverse areas of the metropolitan statistical area (MSA). The uninsured patients in Houston may need to travel to a centralized location to receive care but are assured care once they arrive at that hospital.


GIS has proven to be a valuable tool for enhancing the analysis of hospital and health system data in TrendWatch. Maps are easy to understand and allow TrendWatch readers to examine health service delivery in a spatial context. The June 2000 issue of TrendWatch used numerous maps to explore America's safety net and issues such as utilization and supply of health care services and differing service delivery methods. The use of GIS has enhanced TrendWatch and allowed for a deeper geographical analysis of hospital data. Since the issue of access to health services is in many respects a geographical one such spatial display of data is, in many ways, essential.

For more information, contact

Elisabeth Dowling Root, Research Analyst
The Lewin Group
3130 Fairview Park Drive, Suite 800
Falls Church, Virginia 22042
Tel.: 703-269-5935
Fax: 703-269-5501


American Hospital Association Web site (

American Hospital Association. 2000. Essential Access--Broadening the Safety Net. Washington, DC: American Hospital Association.

Institute of Medicine. 2000. America's Health Care Safety Net: Intact but Endangered. Washington, DC: National Academy Press.

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