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Status of discussion regarding liver distribution

Published on: Tuesday, December 2, 2014

Statement from David C. Mulligan, M.D., FACS, Chair, OPTN/UNOS Liver and Intestinal Organ Transplantation Committee

On behalf of the OPTN/UNOS Liver and Intestinal Organ Transplantation Committee, I thank you for your input and participation in our ongoing study of ways to better ensure fair transplant access for liver candidates nationwide. We want to update you on the status of these efforts.

The September 16 public forum yielded many valuable insights. Our committee met the next day to review what we heard and identify common themes for further study. They fell into four basic areas of emphasis:

  • Refining metrics of access disparity and ways to optimize distribution
  • Identifying financial implications of alternative sharing methods
  • Addressing transportation/logistical issues associated with potential broader sharing
  • Increasing liver donation and utilization

Three ad hoc subcommittees have been formed to study the first three topics in greater depth, as they relate to the Liver Committee’s specific quest to reduce geographic variation in severity of illness at transplant. We have made special effort to include subcommittee members who are not current members of the committee but who have valuable expertise on these issues. The issue of increasing liver donation and utilization is a parallel effort, identifying issues that may apply broadly to any system improvement; our committee has revived an earlier subcommittee to address this topic. These groups will meet by conference call multiple times between November and April to develop consensus-based recommendations.

We believe it is crucial for their findings to be shared with the liver transplant community and the public. For this reason, we plan to host another public forum to share the subcommittee’s recommendations and again seek professional and public feedback to guide our policy development process. While we haven’t yet established a specific date for the forum, we are anticipating a mid-May event if the recommendations can be finalized in the next few months. We will provide you more detailed information as soon as possible.

Another theme that emerged in forum discussion was uncertainty regarding the optimization process used to develop the current conceptual maps. To clarify this issue, the methodology relies solely on current distribution of transplant candidates and liver donors throughout the country, with certain assumptions and constraints our committee established for analysis. The parameters are listed on page 9 of the concept document distributed in June 2014.

Under this optimization protocol, the selection of an additional or alternative metric (for example, calculated MELD at transplant) would not result in different maps. The 4- and 8-district maps were outputs of optimization modeling designed to create more equitable sharing areas. Optimization models were based on current geographic organ supply and current listing data, together with a set of assumptions and constraints specified by the committee (Gentry, et al., Liver Transplantation 20:1237–1243, 2014; Gentry et al., American Journal of Transplantation; 13: 2052-2058, 2013).

Using these maps as a starting point, simulation modeling is used to examine disparity metrics, such as the variance in the median allocation MELD score at transplant. The ad hoc subcommittee studying metrics of disparity and optimization will address these issues, including any recommendations for alternative or additional metrics for examining geographic variation in access to liver transplantation, which is the specific problem the Committee is addressing as mandated by the HHS final rule. As always, the results of any modeling will be shared with you for your questions and additional feedback.

There are various factors that could result in a revision to the conceptual distribution maps. These may include:

  • Underlying changes in data on transplant candidates and/or donors
  • Changes to the liver allocation system (MELD or PELD criteria) that impact severity of illness at transplant
  • Changes to the assumptions/constraints developed by our committee in developing the maps (for example, number of districts or minimum/maximum number of centers per district)

As our committee continues to discuss these alternatives, we welcome your continued interest and participation. We will continue to provide you updates as we have more detailed information and opportunities for your feedback. In the meantime, you may access all of our committee reports to the OPTN/UNOS board, and contact us at any time via e-mail at liver@unos.org.