Use redistricting maps to make organ allocation more equitable, researchers advocate

July 11, 2013, Johns Hopkins University School of Medicine

Using the same type of mathematical formulas used to draw political redistricting maps, Johns Hopkins researchers say they have developed a model that would allow for the more equitable allocation of livers from deceased donors for transplantation.

Currently, in the United States, where you live dictates the availability of a transplant. Studies show that geography can mean the difference between a 10 percent chance of dying while on the waiting list for a , and a 90 percent chance, the researchers say. The new model depends not on the longstanding relationships among medical centers used to create the current unbalanced system, but on making the distribution of organs as equitable as possible, they say.

"This is gerrymandering for the public good," says study leader Dorry L. Segev, M.D., Ph.D., an associate professor of surgery and epidemiology at the Johns Hopkins University School of Medicine. "We have applied to transplantation the same math used for political , school assignments, wildlife preservation and zoning issues." A report on the research is published in online in the American Journal of Transplantation.

"Some geographic areas have very good access to donated organs and some have desperate gaps between organ supply and organ demand," says co-author Sommer Gentry, Ph.D., a research associate in the department of surgery at Johns Hopkins and an associate professor of mathematics at the U.S. Naval Academy. "Our model helps decrease geographic disparity. It's not fair that where you live so vastly affects your ability to get a transplant. We want to fix that."

Currently, patients with the most severe disease go to the top of the liver transplant waiting list. But the list isn't a single national list; instead, it is subdivided according to location. Thus, the sickest person in one region may be much sicker than the person in a nearby region who gets a new liver, simply because the second region has a greater supply—or smaller demand—for organs.

In 2009, the late Apple founder Steve Jobs, who lived in Northern California, famously underwent a liver transplant in Memphis, Tenn. There, he had put himself on one of the shortest waiting lists in the country. In Tennessee in 2006, it took 48 days to receive a liver transplant, compared with 306 days nationally. Jobs was able to do this because he had the financial resources to immediately fly to Tennessee when the liver became available. His situation brought national attention to the large geographic disparities in liver transplantation.

Segev, a transplant surgeon, says that if a patient from San Francisco or New York City needed a liver transplant, it would be difficult to recommend one of the great transplant centers in those cities because the wait is so long.

In developing their new allocation model, the Johns Hopkins researchers essentially redistricted the regions by analyzing supply, demand and access factors for 6,700 deceased donors, 28,063 candidates and 242,727 changes in 2010 to what is known as MELD (Model for End-Stage Liver Disease), a score that categorizes the sickest patients on the list at any given time.

The optimal regional sharing map they created would reduce geographic disparity by half, while significantly reducing waitlist deaths.

Segev, the director of clinical research for transplant surgery at Johns Hopkins, says that the geographic disparity in the current allocation system violates government rules that say geography shouldn't affect organ supply.

He says he hopes the United Network for Organ Sharing, the private, nonprofit organization that manages the nation's organ transplant system under contract with the federal government, will act on this new model.

Explore further: Most liver transplant candidates receive donation offers

Related Stories

Most liver transplant candidates receive donation offers

October 22, 2012
Most liver transplant candidates who died or were removed from the transplant list actually received one or more liver donation offers, according to a recent UCSF study.

Split liver transplants for young children proven to be as safe as whole organ transplantation

June 10, 2013
A new study shows that when a liver from a deceased adult or adolescent donor is split into two separate portions for transplantation—with the smaller portion going to a young child and the larger to an adult—the smaller ...

Changes to distribution of livers for transplant proposed

September 9, 2011
Transplantation specialists have proposed changes to the allocation and distribution of organs used for liver transplants. The recommended policy modifications take into account the scarcity of available organs, ensuring ...

Take a kidney transplant now or wait for a better one? Researchers create 'decision' tool

April 9, 2013
Johns Hopkins scientists have created a free, Web-based tool to help patients decide whether it's best to accept an immediately available, but less-than-ideal deceased donor kidney for transplant, or wait for a healthier ...

Many patients who die while awaiting liver transplant have had donor organs declined

November 5, 2012
The majority of patients on the liver transplant waitlist who died received offers of high-quality donated livers that were declined prior to their death, according to a new study in Gastroenterology, the official journal ...

After years of growth, fewer transplants done through 'kidney chains'

March 12, 2013
An additional 1,000 patients could undergo kidney transplants in the United States annually if hospitals performed more transplants using paired kidney exchanges, new Johns Hopkins research suggests.

Recommended for you

Drug may help surgical patients stop opioids sooner

December 13, 2017
(HealthDay)—Opioid painkillers after surgery can be the first step toward addiction for some patients. But a common drug might cut the amount of narcotics that patients need, a new study finds.

Children best placed to explain facts of surgery to patients, say experts

December 13, 2017
Getting children to design patient information leaflets may improve patient understanding before they have surgery, finds an article in the Christmas issue of The BMJ.

Burn victim saved by skin grafts from identical twin (Update)

November 23, 2017
A man doomed to die after suffering burns across 95 percent of his body was saved by skin transplants from his identical twin in a world-first operation, French doctors said Thursday.

Is a common shoulder surgery useless?

November 21, 2017
(HealthDay)—New research casts doubt on the true effectiveness of a common type of surgery used to ease shoulder pain.

Study shows electric bandages can fight biofilm infection, antimicrobial resistance

November 6, 2017
Researchers at The Ohio State University Wexner Medical Center have shown - for the first time - that special bandages using weak electric fields to disrupt bacterial biofilm infection can prevent infections, combat antibiotic ...

Obesity increases incidence, severity, costs of knee dislocations

November 3, 2017
A new study of more than 19,000 knee dislocation cases in the U.S. between 2000 and 2012 provides a painful indication of how the nation's obesity epidemic is changing the risk, severity and cost of a traumatic injury.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.