UNOS aims to reform imbalances in donor liver distribution

Last Updated: 2016-11-03

By Anne Harding

NEW YORK (Reuters Health) - Where you live in the United States has long determined how sick you need to be in order to get a liver transplant, but the Organ Procurement and Transplantation Network (OPTN) and the United Network for Organ Sharing (UNOS) are battling to change that, and facing resistance from transplant community members who feel they would lose out under a recently proposed plan.

UNOS's Liver and Intestine Transplant Committee has gone back to the drawing board after releasing a draft proposal of its redistricting plan for public comment from August 15 to October 15. Most of the nearly 1,100 comments received were either strongly for or strongly against the proposal.

"We're continuing our efforts in trying to resolve this issue and come to a consensus among the transplant community, which is obviously quite difficult when there are perceived winners and losers," Dr. Ryutaro Hirose, a professor in clinical surgery at the University of California, San Francisco and chair of the committee, told Reuters Health. "We want to still evaluate the various options that have been presented. We're never going to come up with a 100% consensus."

Right now, he said, "there are areas of the country that you have to get a lot sicker to get a liver transplant than in other areas of the country." While people with money and good insurance who need a liver can take advantage of this system and move to a region with a better supply, he added, "the folks that can't move and don't have resources don't have that ability."

In response to geographic disparities, the U.S. Department of Health and Human Services implemented a rule in 2000 stating that allocations should be based on sound medical judgment and seek to achieve the best use of donated organs, and "shall not be based on the candidate's place of residence or place of listing," except as needed to satisfy the above requirements.

Problems with the system stem from the fact that OPTN was established in 1984, when there were just four liver transplant centers in the U.S., Dr. Hirose said. Now, there are more than 100.

In the current system, the country is divided into 58 donor service areas (DSAs) each with its own organ procurement organization (OPO), and DSAs are organized into 11 regions.

The committee's redistricting plan would redistribute DSAs into eight regions, mathematically optimized to promote more equitable organ distribution. This plan is projected to reduce total mortality while slightly increasing organ transplant distance and times.

Dr. Sanjay Mehrotra of Northwestern University in Evanston, Illinois, has developed an "optimized neighborhoods" approach that he argues would be a more effective way to improve liver allocation. Rather than dividing DSAs into fixed districts, the new plan would arrange DSAs into 58 neighborhoods, with each DSA having a specified set of neighboring DSAs. Two adjacent DSAs would share some of the same neighbors.

"Increasing a DSA's connectivity and creating overlapping neighborhoods promotes resilience in responding to demand and supply uncertainty; and balancing supply and demand across neighborhoods ensures greater equity," Dr. Mehrotra and Northwestern PhD candidate Vikram Kilambi explain in their proposed plan, published online October 7 in Transplantation.

Organ distribution would still follow the current local-regional-national model, Dr. Mehrotra noted, with the only difference for DSAs being how the organs are shared during regional allocation. The new approach is similar to the concentric circle system now in use for allocating donor hearts and lungs, he added, but "we put more science behind it."

Given the emotional and political nature of organ donation and transplantation, he added, "we wanted to leave the politics aside . . . . if people's lives are at stake we should try to minimize politics and let science drive the decision."

The Liver and Intestine Transplant Committee is currently evaluating three different approaches: redistricting, as described in its proposal; optimized neighborhoods; and concentric circles.

"So far, from all of the things that we've looked at in terms of the mathematical model, all three alternatives would be far better than the current system in terms of getting rid of this current geographic disparity," Dr. Hirose said. One advantage the redistricting approach has over the others, he added, is its similarity to the existing system, so it would be simpler to implement than a more radical change.

"There are folks that have it pretty good right now in terms of how many donors that they have in their area," Dr. Hirose said. "They feel that if they have to 'share' their organs their volume of transplants might go down."

"The question is whether the transplant community itself can come up with a solution for itself for a problem that we all know exists," Dr. Hirose said.

SOURCE: http://bit.ly/2fHZN4N

Transplantation 2016.