The Model for Endstage Liver Disease (MELD) score was implemented in February 2002 to serve as the basis for the liver allocation system used by the United Network for Organ Sharing.
The MELD score is an objective scoring system of medical characteristics predictive of prognosis, with minimal emphasis on waiting time as a priority for transplantation.
However, recommendations to increase and standardize the size of the area of organ allocation have not been implemented.
|The distribution of patients' MELD scores listed for transplantation was the same.|
|Journal of the American Medical Association|
Consequently, there is great disparity in the patient populations served by organ procurement organizations (OPOs) across the United States.
In some regions of the United States, an OPO may serve as few as 1.2 million people, whereas in other areas, the population covered by the OPO is nearly 18 million.
The smallest OPO has fewer than 10 patients listed for liver transplantation, whereas the largest has more than 2000.
Dr James Trotter and Michael Osgood of the University of Colorado Health Sciences Center, Denver, conducted a study to determine whether there is a difference in MELD scores for liver transplant recipients receiving transplants in small versus large OPOs.
The researchers reviewed data from the US Scientific Registry of Transplant Recipients between 2002 and 2003.
Overall, 4798 transplant recipients had end-stage liver disease and received deceased-donor (DD) livers.
The authors examined MELD score distribution, graft survival, and patient survival for liver transplant recipients in small (less than 100) and large (100 or greater on the waiting list) OPOs.
The researchers found that the distribution of patients' MELD scores listed for transplantation was the same in large and small OPOs: 92% had a MELD score of 18 or less, 7% had a MELD score between 19 and 24, and only 2% of listed patients had a MELD score higher than 24.
They found that the proportion of patients receiving transplants in small OPOs and with a MELD score higher than 24 was significantly lower than that in large OPOs (19% versus 49%).
Patient survival rates at 1 year after transplantation for small OPOs (86%) and large OPOs (87%) were not statistically different, and neither were graft survival rates in small OPOs (80%) and large OPOs (81%).
"In summary, we report that a significantly smaller proportion of adult DD liver transplant recipients in OPOs with small waiting lists receive transplants and have a MELD score higher than 24 compared with recipients in large OPOs.
"The most likely explanation for this disparity is that DD livers are preferentially retained for transplantation in the local OPO, where the number of patients with high MELD scores is numerically smaller than that in large OPOs.
"Although this disparity does not reflect the mandate of the final rule, there may be advantages for selected patients.
"Transplant professionals should be aware of this disparity and its implications as they continue to amend regulations for organ allocation," the authors conclude.