Visualizing the Data: GIS Steers Professor Toward Health Care Policy Solutions

Posted: March 30, 2009 at 1:00 am, Last Updated: November 30, -0001 at 12:00 am

GIS map
The map above shows concentrations of pneumonia patients in the greater Philadelphia area.
Image courtesy of Naoru Koizumi

By Colleen Kearney Rich

Naoru Koizumi loves solving a mystery. She enjoys discovering “hidden facts” and uses computer modeling and simulations, as well as geographic information systems (GIS), to “tease out” answers to important questions.

Naoru Koizumi
Naoru Koizumi
Photo courtesy of Naoru Koizumi

“[These methods] often reveal information that wouldn’t necessarily be found through statistics alone,” says Koizumi, an assistant professor in Mason’s School of Public Policy. “Sometimes if you visualize [the data], the answer is so obvious.”

Integrating Health Care and Geography

After completing an undergraduate degree in business administration from Aoyama Gakuin University in Japan, Koizumi traveled to the United States to study regional science at the University of Pennsylvania.

While in the PhD program, she had the opportunity to work with medical school researchers and realized that she was very interested in integrating health care and epidemiological issues topics with geography and regional issues.

After completing her degree at Penn, she pursued another PhD, this time in environmental and preventive medicine at Hyogo College of Medicine in Japan.

By following this particular pathway, Koizumi has carved herself a niche. Many of her research projects have involved applying GIS or modeling to health care problems or issues.

During her career, she has used spatial techniques and simulations to examine a number of health issues, including kidney transplants in England and the United States; cadmium concentrations in rice and renal failure mortality in Japan; and drug-resistant pneumococcal rates in U.S. inner cities.

Congestion in the Mental Health System

Mental health system congestion is a subject of ongoing analysis for Koizumi. Her interest in this area began with her dissertation.

Koizumi examined the causes of patient flow congestion in a psychiatric care system, using Philadelphia as a case study. The results of her study were surprising and contrary to popular perceptions.

By creating a model of the system, Koizumi found that systemwide congestion was due to shortages in supported housing and not due to a shortage of beds throughout the system.

By increasing the number of supported-housing placements, the final stop in the system where patients could begin to get on with their lives while still receiving some services, the City of Philadelphia could alleviate congestion throughout the psychiatric care system.

“It was the bottom of the system that was working as a bottleneck,” Koizumi says, “and it was not something the health care administrators would have been able to see. They can only look at the part of the system they are involved in. Perhaps the most important policy implication of this analysis is that removal of such facility-specific bottlenecks may often be the most cost-efficient way to reduce congestion in the system as a whole.”

Policy Implications

All of Koizumi’s analyses have had policy implications.

With her cadmium research, she measured the association between cadmium intake through normal diet and renal failure using the data from 37,250 locations across Japan.

The results were informative for the government of Japan in negotiating the most recent Provisional Tolerable Weekly Intake (PTWI) of cadmium, the internationally set threshold level of contamination.

In her current kidney transplant research, Koizumi is finding that, particularly in the United States, the patient’s proximity to a treatment facility is one of the greatest factors affecting racial disparity in accessing a transplant.

For this research, she is teaming with researchers in London to compare the systems in the United States and Europe.

“Europe has a completely different [transplant] system and a more complicated allocation protocol. We are interested in how different allocation systems affect the access across different groups,” she says.

“Everyone should have an equal opportunity of getting treatment, and that brings up policy. What kind of policy could we formulate to ensure these patients get to hear what their treatments options are, regardless of where they live? I think that is an interesting question.”

With funding from the National Institute of Mental Health, she also is working on an extension of her doctoral project on mental health systems that captures the differences in treatments depending on patient diagnoses and a cost optimization model, using Delaware and Pennsylvania as primary research sites.

“The goal of this project is to create a decision support tool for mental health policy makers,” she says.

In addition, Koizumi has begun working with Faye Taxman in Mason’s Department of Administration of Justice, an expert in correctional systems and recidivism.

“A lot of mental health issues are being ‘treated’ in prison and correctional systems,” says Koizumi. “In a way, prisons are becoming mental hospitals, and that’s also creating congestion in the correctional system.”

“Recidivism is a big problem for inmates with mental health issues. [Research has shown that] if you have a mental health episode, you are much more likely to go back to jail and prison,” she continues.

“How can the mental health system be revised so we can treat those people outside of prisons? What kind of treatment is most effective in the correctional system, and what’s most effective outside? Those are some of the questions we hope to find answers to by using dynamic modeling.”

This article originally appeared in Mason Research 2009.

Write to at