New System for the Distribution for Donated Livers

Thanks to a new allocation system for liver transplants that gives preference to patients that have the greatest need—rather than the time they have spent on a waiting list—racial disparities among those waiting for a liver transplant are narrowing.

African Americans are no longer much more likely to die or become to sick to receive a transplant while being on the waiting list, however, there are still some noticeable gender gaps, according to the most recent study published in the November 26th issue of the Journal of the American Medical Association.

A new scoring system for MELD (Model for End-Stage Liver Disease) was introduced in the year 2002. Dr. Cynthia A. Moylan, the lead author of the new study and a transplant hepatology fellow at the Duke University Medical Center in Durham, N.C., said, “Post-MELD, the disparity between blacks and whites went away.” Now, the patients that are the sickest get the new organs first.

This new study is the first comprehensive look at the success the new system has had. Currently in the United States, there are more than 16,000 people waiting for a liver transplant, according to the United Network for Organ Sharing (UNOS). Also, according to an accompanying editorial in the journal, the overall rates of survival for liver transplantations normally exceed 90 percent post procedure. A liver transplant is the single hope for long-term survival for patients with end-stage live disease.

Before 2002, allocation of livers from the deceased donors was based on the time they spent on the waiting list, as well as subjective measures that were made my a physician. The old system has been found to have multiple problems, and one of them was racial disparity. African Americans were underrepresented on the waiting list and were less likely to receive a liver transplant.

Dr. Richard Freeman, a professor of surgery at the Tufts University School of Medicine in Boston and chairman of the committee that put the MELD system into effect, explained that the people who were able to wait for a long period of time were found to be less likely to need a transplant. Also, the system before 2002 could be manipulated. For instance, some patients that were in intensive care were give preferential status, so that the doctors sometimes put patients in the ICU to bump them up further on the waiting list. The physicians were only trying to do what they thought was best for their patients, but it was disadvantaging those that really did need a liver transplant.

The MELD score, which can predict the risk of the patient dying within three months, is based on a formula that incorporates three laboratory tests. Freeman said, “MELD is based on pure blood tests, and it’s hard to manipulate patients’ blood tests. The waiting time is taken out. It’s based on who’s sicker.”

The authors of this new study looked at the patients that were both white and black on the Organ Procurement and Transplantation Network waiting list for a liver transplant between January 1, 1996 and December 31, 2000 (before MELD), and between February 28, 2002 and March 31, 2006 (after MELD).

Before the MELD scores, approximately 27 percent of African American patients died or became to sick to have a transplant within three years of registering for having transplant, compared to approximately 21.7 percent of whites. Post-MELD, the gap narrowed greatly with approximately 26 percent of African Americans dying or becoming to sick to have a transplant, compared with approximately 22 percent of whites. And while African Americans were less likely than the whites to receive a transplant within three years of registering on the pre-MELD list, in the post-MELD era however, this is not the case.

Gender, however, is another issue for transplants. Women are shown to be more likely to die or become too sick to receive a transplant under the post-MELD system. And women are now, and were then, less likely to receive a transplant within three years, regardless of the era.

This is likely the result of many factors, including women being smaller in size (meaning they needed a smaller liver for transplant), higher likelihood of having an autoimmune disease prior to transplant, and the fact that women have less muscle mass, which likely affects some of the MELD calculations.

Freeman stated that organ allocation in general is constantly changing all the time. You can learn how to do it better and build on experience to figure out what is wrong and right about it. More evidence is still emerging and adding a serum sodium test to the MELD calculation might be right to correct the gender imbalance.