November 01, 2008
|Media contact: Krista Hopson
Patients low on liver transplant list not getting best organs
U-M study finds policy has changed how high-risk organ are allocated
ANN ARBOR, Mich. — An organ allocation policy that puts the sickest patients first in line to receive available donor livers for transplantation has created some unintended consequences for those patients low on the organ wait list, according to researchers at the University of Michigan Health System.
Since the Model for End-stage Liver Disease
(MELD) organ allocation system was implemented in 2002, patients who are least in need of an organ transplant have been receiving livers that are higher-risk, or of a poorer-quality. As a result, the study shows post-transplant survival among non-urgent patients – those with MELD scores that place them lower on the wait list – has gotten worse since MELD was implemented.
“There’s been a shift toward using high-risk organs in patients with lower MELD scores, which has led to a small, but significant decrease in post-transplant survival among these patients,” he says. “What’s striking is that these patients typically have a low pre-transplant risk of mortality, and ultimately derive limited benefit, in terms of survival, from liver transplantation. In some cases, these patients may actually be harmed by a transplant, even with an organ of average quality.”
The study finds:
- The overall quality of transplanted livers has gotten worse since the implementation of the MELD organ allocation system.
- In the five years since the MELD system began, there has been an increased risk for graft failure in patients who are lower on the organ wait list.
- Prior to MELD, higher-risk organs were only given to the sickest patients. Today, however, patients who are least in need of a liver transplant are paired with higher-risk organs.
- As the result of receiving higher-risk organs, there has been a decline in post-transplant survival among patients with low MELD scores.
Under MELD, a patient’s place on the donor organ wait list is determined not by waiting time, but by disease severity. MELD relies solely on objective laboratory data to accurately predict a patient’s probability of death within three months, to maximize patient survival from the limited supply of donor livers. Therefore, the sickest patients – those with the highest MELD scores – are placed at the top of the wait list.
When a donor liver becomes available, the United Network for Organ Sharing reviews the patient wait list, which is prioritized by MELD scores. The physician whose patient is at the top of list is contacted, and he or she must then decide if they want to accept the organ or wait for a better option to become available. Volk explains that in many cases, physicians with high MELD score patients opt to wait for a better liver for their patient - especially when the organ is high risk.
“Physicians often decide to wait for a better option, which then moves a high-risk organ down the transplant wait list. As a result, patients with less severe liver disease are more likely to receive a higher risk organ, which has reduced their post-transplant survival,” says Volk.
The decision to accept or reject an organ is certainly a complex one, which transplant physicians must make quickly and at all hours of the day. Still the study shows that changing the organ allocation process from one based on patients’ time on the wait list and subjective measure of disease severity, to one based entirely upon objective measures of disease severity, has ultimately impacted how physicians decide which organs are best suited to their patients.
With plans to further study this issue, the researchers believe that there may be several factors now affecting transplant physicians’ decisions to give higher-risk organs to patients – the desire to improve a patient’s quality of life, rather than quantity of life; and concern that with a limited supply of available donor livers, a patient low on the list may wait indefinitely for an organ.
Despite the physician being the one to make the final call on an available donor organ, Volk advocates for transplant patients to be informed about the quality of a potential donor organ, as well as have an understanding of the transplant process and MELD.
“Few would dispute that patients have the right to know the quality of organ they receive, but it's unclear how much patients are truly informed,” says Volk. “This is a complex subject, and physicians say that they find it difficult to communicate all the various risks without scaring the patient.”
Volk and his colleagues are currently conducting a study to learn more about this issue, and hope in the future to offer recommendations about how best to educate patients.
Although Volk and his colleagues do not advocate for changing the MELD system, they do recommend increased patient involvement in decisions about organ quality; better education of physicians about the harm caused by allocating high-risk organs to patients with low MELD scores; and changes in the reimbursement system so that managing and transplanting sicker patients are reimbursed at higher rates to remove any incentive to transplant the more stable patients with lower quality organs.
Methodology: The researchers used data from the United Network for Organ Sharing Standard Transplant Analysis and Research for the study. Adults who underwent a deceased donor liver transplant between Jan.1, 1997 and Aug. 1, 2007 – which spans five years prior to and five years following the implementation of MELD – were analyzed. Researchers examined patients’ risk of graft failure, or donor risk index, and survival after transplantation.
Authors: In addition to Volk, study co-authors from the U-M Health System were Anna S.F. Lok, M.D.; Shawn J. Pelletier, M.D.; Peter A. Ubel, M.D.; and Rodney Hayward, M.D.
Funding: The study work was support by a grant from the Robert Wood Johnson Foundation and the Department of Veteran Affairs, and by Health Resources and Services Administration.
Reference: Gastroenterology, Vol. 135, No. 5.