Alternate Kidney Allocation System Could Reduce Transplant Waiting Time

By Charnicia E. Huggins

Some individuals may wait for years to receive a kidney transplant, while others seem to receive their new organ much more quickly. Research shows that African Americans, for example, tend to have longer waiting times for kidney transplants than do whites.

Now a proposed organ distribution system could reduce the median waiting time for kidney transplants from 2 years to 14 months and improve the transplant rates of African Americans and females, according to a report in the July/August issue of Operations Research, the journal of the Institute for Operations Research and Management Sciences (INFORMS), an international scientific society.

The current allocation system used by the United Network of Organ Sharing (UNOS) takes into account some patient characteristics as well as the match between the tissue type of the donor and the recipient. However, some people still receive an organ faster than others.

For example, African Americans are at greater risk for kidney failure and are more likely to need a transplant than other people, but there are fewer black kidney donors. Because blacks are more likely to have a blood type mismatch with whites, they may have to wait longer for an appropriate kidney. "What we have discovered in the process of this research is that demographics play a very important role (in the current system)," lead author, Dr Stefanos Zenios, assistant professor at Stanford University's Graduate School of Business in California told Reuters Health. "You can either give higher priority to certain demographic groups or penalize certain demographic groups even though that is not your initial intention," he explained.

To combat this problem, Zenios and his colleagues developed a policy in which they took into account many factors associated with the potential recipient. While UNOS takes into consideration some patient and organ characteristics, the researchers also looked at prior transplants, body size, gender and race. The system computes a health benefit score for a potential candidate and then adjusts the score for those who repeatedly are on the low end of the health benefits scale, so that they get equal access to transplantation.

"At a more specific level, one example of what our system is doing that UNOS is not doing (is that) we consider policies in which patients who had previous rejection episodes of organs have lower priority," Zenios stated. "That is if you have a candidate who didn't have an organ in the past, that candidate would have the highest possible priority, everything else being equal."

However, the authors admit that their "simulation model has several limitations." Their system does not make any allowance for individuals who may not accept the kidney or for individuals who register for kidney transplants prematurely, thus possibly gaining an unfair advantage. Recognizing the complexities of the kidney allocation problem, the authors write that "devising an effective and fair allocation policy is an arduous task that involves difficult choices." They also acknowledge that "any policy will inevitably be disadvantageous to some groups of patients.

"Ultimately, any recommendation for revising the current allocation policy will only be successful if it meets the stringent requirements of public approval," the authors conclude.

While UNOS is eager to review any suggestions or proposals to better their allocation system, some of the information used in the new study was outdated, according to UNOS spokesperson, Joel Newman. "(It) may have been from 1995-1996," he said. However, UNOS is currently working on a "statistical modeling system for kidney allocation," he said.

This article posted July 30, 2000.

Alternate Kidney Allocation System Could Reduce Transplant Waiting Time

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