A lot of thought and politics goes into changing the rules for which patients get which kidneys, how long they wait, and how much that should play a role in the allocation decision, as opposed to other criteria having to do with how well each kidney fits each patient, what is the age difference between deceased donor and recipient, etc.
John Faherty at the Arizona Republic has written an informative account of the ongoing debate: New rules change who gets donated kidneys
"Dr. Kenneth Andreoni, chairman of the United Network for Organ Sharing Kidney Transplantation Committee, has been working to develop a better way to distribute kidneys since 2004.
"The current allocation system went in decades ago," Andreoni said. "It was based on good science, but it was a different time."
The system was built to balance utility with fairness.
For utility, doctors required that donated kidneys and recipients be a close biological match. It was the only way to ensure that the recipient's body wouldn't reject the organ, wasting a precious donation.
For fairness, they established a waiting list. The people on the list the longest were first in line for the next matching kidney.
But in the 1980s and 1990s, things began to change. Better anti-rejection drugs helped a recipient accept a kidney even if they weren't a perfect match. Before long, the allocation system that was supposed to balance utility - the likelihood of a successful transplant - with fairness - time on the waiting list - was out of whack.
All that mattered was the wait time.
Frustration grew among transplant doctors. Without the criteria of a tissue match, the system was no longer using science to make the best choices.
Doctors were sometimes putting healthy young kidneys into recipients with only a few years left to live."
"The committee is recommending at least two key elements that are almost certain to be part of the new system.
• The first is dialysis time. The current waiting-list system is less fair than it seems, Andreoni said, because some doctors list patients early, at the first sign of kidney failure, while other doctors wait until after other treatments to list their patients. This puts patients in the second group at a disadvantage.
A dialysis-time list would put all patients on equal footing. The longer you have had to endure the treatment, the sooner you can get a kidney.
• The second element is a complex grading system called the Donor Profile Index. Doctors would measure the quality of a donated kidney to determine how well it will work and how long it will last. Then, they would give that kidney to the patient who would most benefit from it.
That means factoring, to a still-undetermined degree, who would get the most use of a new kidney - who would live the longest.
"Right now, whoever is next in line gets the kidney," Andreoni said. "It does not make the best use of the organ." "
Of course, changes like this, when allocating a scarce resource, involve benefits from some people, but not for everyone.
"With the proposed changes to the allocation system, a patient like Ramirez will be more likely to receive a kidney from a younger person, and probably sooner.
"It's a conundrum. A change would be a really good thing for me," she said. "But if I was older, I might be angry. Maybe they have been waiting for a long time." "
That's what makes some changes politically hard. Sometimes phasing such changes in over time may ease the path.
Update: for those of you who don't click on comments, Michael Giberson said... Why not favor patients with an unmatched donor, and so use deceased donor kidneys to trigger a exchange chain. ?
Mixing the deceased donor kidneys with the kidney exchange pool also involves some complicated political issues, since deceased donor organs are regarded as a shared public resource, but live donor kidneys are of course private property.
But in New England we have permission to do something like what Giberson has in mind, called list exchange: see
Roth, Alvin E., Tayfun Sönmez, M. Utku Ünver, Francis L. Delmonico, and Susan L. Saidman, ''Utilizing List Exchange and Undirected Good Samaritan Donation through 'Chain' Paired Kidney Donations," American Journal of Transplantation, 6, 11, November 2006, 2694-2705.
Here's the first paragraph of the abstract of that paper:
"In a list exchange (LE), the intended recipient in an incompatible pair receives priority on the deceased donor waitlist (DD-waitlist) after the paired incompatible donor donates a kidney to a DD-waitlist candidate. A nondirected donor’s (ND-D) kidney is usually transplanted directly to a DD-waitlist candidate. These two established practices would help even more transplant candidates if they were integrated with kidney paired donation (KPD)."
The paper goes on to report an early NDD chain conducted at the New England Program for Kidney Exchange that passed through the exchange pool, i.e. that included patients with incompatible donors in the middle, with the final link being a donation to someone on the DD-waitlist. We have also done exchanges that may be closer to what Giberson suggests, in which a deceased donor kidney goes to someone in the kidney exchange pool, whose incompatible donor gives to someone else in the pool...whose donor gives to someone on the DD-waitlist.