Measuring dialysis to fairly allocate kidneys for transplant

By Bill Peckham

United Network for Organ Sharing (UNOS) is designated as the Organ Procurement and Transplantation Network (OPTN) by the federal government. They are the rule setters for how a limited supply of post mortem kidneys are allocated to a growing number of people waiting for a renal transplant. The OPTN/UNOS Kidney Transplant Committee has put out a Request for Information (RFI) as a way to engage interested parties in the rule making process.

Any responses to the RFI are due by December 18th. Through a well described process the committee has come to certain conclusions on how to improve the allocation of kidneys, the RFI (PDF link) is a final step to making the proposed changes. The RFI's Executive Summary gets to the point:

The OPTN/UNOS Kidney Transplantation Committee conducted an extensive, three-year long review of kidney transplantation. From these deliberations, the Committee found that the current allocation system has several limitations. First, the current kidney allocation system is heavily reliant upon the length of time a candidate has been on the OPTN Waiting List. Unlike the liver and lung allocation systems, kidney allocation is not based on a number of other available objective medical criteria. Secondly, the current system does not match donors and recipients well. The result is that kidneys with long projected post-transplant survival commonly are allocated to candidates with expected short post transplant survival. Partly as the result of this allocation, death with a functioning graft is now the most common cause of kidney graft failure. Finally, unlike the allocation systems for livers and lungs, the Committee found that the current kidney allocation system has no agreed upon central goal such as reducing wait list mortality or improving post-transplant survival.

The Committee concluded that the current system could be improved by the inclusion of several new allocation concepts including:

• Ranking candidates based upon objective medical criteria using survival with transplant compared to survival with dialysis, termed Life Years from Transplant (LYFT).
• Classifying of donor kidneys with a continuous measure called a donor profile index (DPI).
• Changing waiting time from time since being added to the OPTN Waiting List to the time from the start of dialysis (DT) regardless of when the candidate was listed.

These three major concepts could be combined in a novel way so that candidates have equitable access to deceased donor kidneys, and those donor kidneys are matched more appropriately with potential recipients. In this system, kidneys with longer potential for survival would be allocated primarily to candidates with longer expected survival. This approach should result in fewer re-transplants and lower rates of death with a functioning graft.

The whole document makes for interesting reading but I would be interested in knowing on what dose of dialysis will they base their comparison? Both the "survival with transplant" and the "survival with dialysis" would depend on the dose of dialysis. The Freedom study from NxStage shows a higher graft survival when transplant is proceeded by higher doses of dialysis and many studies indicate that people with CKD5 live longer when they receive more dialysis than the conventional 3x/week, incenter dose.

Acknowledging the survival advantage of high dose dialysis would, I think, change the allocation of kidneys. If someone could not dialyze more frequently - because of home situation or lack of a fistula - they would have a higher LIYT than a person dialyzing more frequently at home. Except against this gain you'd need to reckon the extended life span of the transplanted kidney. It's a grim calculus.I think the UNOS/OPTN allocation advantage would go to the person on conventional dialysis i.e.conventional dialysis is more of a longevity disadvantage than preceeding transplant with a high dose of dialysis is an advantage.

Comments

[Alison Hymes]

Even though it would have meant a longer wait for me, I think they should address the current inequity in transplant waiting times based on where a person lives/their region first. I also think inequities based on income need to be addressed. Folks who have the money can 1)multi-list somewhere with a shorter waiting time than their own region and 2) people without good insurance and money saved or a good paying job, especially young people facing years of paying for anti-rejection drugs either don't qualify for the UNOS list or don't even try to get on it because of the financial burden they can not meet. I don't believe it is just for organs to be distributed based on the income of the recipient especially when this disadvantages the young who have the most years to gain in most cases or for whom a transplant can mean the chance to have a child or not. As I say, I would have waited longer, and I am glad I did not have to, but I could have waited longer and a young person in our area's obituary was in the paper a few weeks after my transplant (only 29) which made me very sad and frankly gave me some survivor guilt.

[Jessica]

It is legal to abort a child from a womb but you can't sell your kidney to save a life.. I would $$ my kidney in a heartbeat to save a life,,
36life@live.com