There are nearly 100,000 patients on the transplant waiting list for a deceased donor kidney transplant in the United States, including more than 600 here at the University of Chicago Medicine. But each year only about 11,000 people receive transplants from a deceased donor. An additional 5700 individuals receive the gift of life from a living donor.
Deceased donor kidneys are a scarce resource, and the rules for allocating them to patients are fraught with ethical questions. For the past eight years, the United Network for Organ Sharing (UNOS), the non-profit organization that manages the organ transplant system with the United States government, has been trying to revise its system for allocating kidneys from deceased donors to improve efficiency fairly.
In June of 2013, they approved significant revisions to the allocation policy, intended to increase access for all groups of candidates while improving success rates for those receive transplants. The new rules are expected to go into effect at the end of 2014.
Yolanda Becker, MD, is the director of the kidney and pancreas program at the University of Chicago Medicine and serves on the board of directors for UNOS. I spoke to her recently about the changes to the allocation system, why they have been so controversial and how she thinks the new system will improve access for more patients in need of a kidney transplant.
Why was there a need to overhaul the current allocation system?
The whole reason was that there were disparities with minorities and certain geographic areas. The new allocation system does not necessarily tackle geographic disparities, but really tried to diminish ethnic and minority disparities in access to transplant. Allocation is based upon a complex point system, and in the current system, the points started adding up when somebody got to the waiting list. So you could imagine, if you are a very savvy medical consumer, then you get to the waiting list a lot faster than those people who have less access to healthcare This was a clear disadvantage to some individuals.
How is the new system designed to fix this?
We basically reinvented the wheel. The new system gives the patient points based upon when they start dialysis. For instance, someone who has been on dialysis for 5 years comes to our center for evaluation for kidney transplant. In the old world he starts from point 0. In the new world he has 5 years, or five points, of waiting because he’s been on dialysis for 5 years.
These changes have been pretty controversial though. What are some of the objections to it?
Donor kidneys are a scarce resource. There’s no fair way to give them out. But there is a distinct point in time at which somebody started dialysis, and that is less subjective than when you went to a doctor and that doctor refers you to a transplant center.
I actually think it’s a better system, because not only did we look at waiting time being calculated from the time that somebody starts dialysis, but we also changed the way we evaluate donor kidneys. In the current system, basically there’s a pot of kidneys that are considered “standard criteria” donor kidneys from younger donors, and a pot of kidneys that are considered “extended criteria” donor kidneys from older donors. It’s one or the other, and that’s all that basically matters, with the exception of two or three medical conditions. But there’s a big intersection of older donors that might actually have better kidneys than younger donors, and we don’t calculate that.
How does the new system look at those donor kidneys differently?
The new system has 10 criteria for evaluating a donor kidney. Those 10 criteria all get weighted and given a score called the KDPI, or the Kidney Donor Profile Index. The score goes from 0 to 100. Anything over 85 is considered a riskier kidney, what’s been traditionally considered the extended donor criteria kidney.
With this new score, the patient can participate in the decision about whether the transplant is the best option. They understand the idea of, “What are my chances?” If your chances of having a complication with dialysis are greater than your chances of having trouble with this transplant kidney, then the decision is easy.
How does that score affect how the kidneys are allocated?
In the new allocation system, the kidneys with the best scores are also going to be preferentially allocated to those patients who have the best estimated post-transplant score. That score is not going to be gameable, like when you get referred to your doctor. The estimated post-transplant survival is based on whether or not you have diabetes, how old you are, whether or not you had a previous transplant and how long you’ve been on dialysis. Again, there were lots and lots of arguments about this among transplant professionals. There’s a lot of concern, but in the new system, the best 20 percent of kidneys now are going to get allocated to those patients who are estimated to have the longest post transplant survival. Basically what we’re trying to do is get the correct kidney into the correct patient and prevent the need for re-transplantation.
With this new allocation system, it’s estimated that we’ll save 8,000 years of transplant life by preventing re-transplant.
Will this new system help increase the number of patients who can get transplants?
It depends. The supply of kidneys didn’t get any bigger. and the recipient list keeps growing. I wish we could educate people about organ donation so that every individual who could donate did donate and every family would consider donation even at a time of unexpected loss. We would still have a shortage but not nearly what we have. If everybody who could potentially donate a living donor kidney would be evaluated, we’d have even more lives saved or enhanced. The new system won’t increase the absolute number of organs currently available, but by decreasing the need for retransplant, we hope that more kidneys are available to patients receiving a kidney for the first time.