By now, you have most likely heard about the United Network for Organ Sharing’s Concepts for Kidney Allocation, which outlines potential changes to the way deceased-donor kidneys are, so to speak, “distributed” to any of the 85,000 people currently waiting for one. Depending on your source, however, what you have heard about the concept document probably varies from “It is an effort to make the best use of a limited resource” (true) to “No one over the age of 60 will get a kidney!” (erroneous and also, frankly, outrageous).
The simple fact is that there are not enough available kidneys in the United States to make a dent in the waiting list. UNOS’s concept document does not address the issue of how to increase donations (one manufactured controversy is sufficient for a single document). What it does is provide a rationale for ensuring that each available kidney finds its best possible match.
“We’re not going to create any new kidneys with this, unfortunately,” says John J. Friedewald, MD, Vice Chair of UNOS’s Kidney Transplantation Committee and Assistant Professor in Medicine–Nephrology and Surgery at Northwestern University. “What we are going to do, the idea of this, is to give the right kidney to the right person.”
Tremendous Shift in Transplant Recipients
Just who is the right person for each kidney? And why, after years of the traditionally accepted “first come, first served” method, would the US even need a change in plan?
For one thing, statistics from the US Renal Data System paint a picture of a changing kidney transplantation system. In 1991, three in 10 patients were older than 50; by 2008, that proportion had doubled to six in 10, and one in six was older than 65. Since 2000, the transplantation rate has decreased 30% for persons ages 29 to 50 and increased 49% for those older than 65.
“All of a sudden, we’ve had this tremendous shift, which has only just begun, to transplanting an elderly population,” says Barbara Weis Malone, CFNP, Senior Instructor in the Division of Renal Disease and Hypertension at the University of Colorado Health Sciences Center. “I remember when I started in the transplant community nine years ago, we would barely look at a 60-year-old, and now, regularly, we are transplanting 64-year-olds and occasionally even putting people at 70 on the transplant list.”
At the same time, the average deceased donor is still from among the younger portion of the population, which can lead to serious disparities between graft longevity and recipient longevity. No one is saying older persons don’t deserve a kidney as much as younger persons—but, realistically, does a 68-year-old man need a 6-year-old’s kidney?
“Currently, our system can give a very long-lived kidney to a person who is not expected to live very long,” Friedewald points out. “And vice versa, which is sometimes worse—give a short-lived kidney to someone who is expected to live really long. What that means is that person, usually a younger person, may need a second or even third transplant in his or her lifetime.”
Almost 15% of the waiting list represents people waiting for their second, third, fourth, or even fifth transplant, Friedewald says. Part of the return on investment if the concept document becomes policy could be a reduction in that number. “If we give organs to younger people who are going to live a long time with them, then eventually—not tomorrow; maybe in five, 10, or 15 years—there will be fewer people returning to the wait list,” according to Friedewald. (But we’re getting ahead of ourselves, because the document cannot even be accurately termed a proposal at this point.)
For clinicians in nephrology, seeing the current allocation system in action can be distressing, even though they want to provide the best care to all patients. A sweet, 66-year-old grandmother may end up with an 11-year-old’s kidney, while a 20-year-old, otherwise healthy man with glomerular nephritis may spend years waiting and not get the kidney he ideally needs, one that will last 30 years or longer.
“When I first came into kidney transplant, I thought, ‘It’s just the first person in line; that’s wonderful,’” says Weis Malone. “But now it kind of breaks my heart. As a medical professional, it’s hard to see your younger population who could really use a kidney tomorrow.”
In essence, along with the disparities comes a sense of wasted opportunity. “One in three people dies with a functioning kidney,” says Kim Zuber, PA-C, MSPS, DFAAPA, Chair of the National Kidney Foundation Council of Advanced Practitioners, who practices at Metropolitan Nephrology in Alexandria, Virginia, and Clinton, Maryland. “As far as I’m concerned, that’s a waste, because the kidney should fail before you die; then you’ve used it all up.”
And for those who insist that “first come, first served” is fair, Friedewald has a different opinion, calling it “a complete fallacy. The first come aren’t the first served. Some people won’t live long enough to wait for a kidney, if the line is too long. Everyone believes that a line is ‘first come, first served,’ because we’re used to delis and things like that, where you actually get served. But a lot of people aren’t getting served.”
That may never change, but the concepts outlined in the UNOS document aim to achieve an additional 15,223 life-years lived with a transplanted kidney for every year’s worth of deceased-donor transplants. How? Let’s explore.
How the System Would Change
Early on, Concepts for Kidney Allocation (available at optn.transplant.hrsa.gov/SharedContentDocuments/KidneyConceptDocument.pdf) outlines the flaws of the current system: “[I]t does not strive to minimize death on the waiting list nor maximize survival following transplant. It does not recognize that all candidates do not have the same ability to survive the wait. It does not attempt to match the characteristics of a donor’s kidney to the candidate’s characteristics to promote a long and healthy survival post-transplant. The system can be better, and it can be designed to achieve more in the way of health and longevity than it currently does.”
Aware of the problems, and with input from hundreds of individuals—including transplant professionals, recipients, and candidates, as well as donor families, living donors, and the general public—UNOS’s Kidney Transplantation Committee has spent six years (so far) developing goals for a new allocation system. The concept document delineates three key factors in achieving those goals:
• Utilizing a kidney donor profile index (KDPI), a continuous measure used to estimate the potential function of a donated kidney if it were transplanted into the average recipient, to better characterize donor kidneys.
• Allocating some kidneys (20%) by a combination of the KDPI and a candidate’s estimated post-transplant survival (EPTS).
• Allocating the majority of organs (80%) by age-matching so that candidates within 15 years older or younger than the donor are prioritized.
The KDPI is based on the characteristics of the donor, including age, race/ethnicity, height, and weight, and whether he/she had any of the following factors: hypertension, diabetes, hepatitis C, elevated creatinine level, a cerebrovascular cause of death, or cardiac death. It is important to remember that a score below 20% indicates a kidney with the predicted longest function; it’s like being in the top 20% of your graduating class.
A candidate’s EPTS is based on age, length of time on dialysis, diabetes status, and history of prior organ transplant. “While no calculation will be able to predict life expectancy with 100% certainty, these four factors provide a reasonable estimate for identifying those candidates who have the longest possible EPTS,” the committee writes.
Once a KDPI has been established, there are two scenarios for how a candidate might be selected. Kidneys with a KDPI of 20% or lower are allocated based on EPTS. Those with a KDPI of more than 20% are allocated based on age-matching within 15 years (older or younger) of the recipient’s age.
To use the examples given in the report: Let’s say there are three candidates for a kidney. Mary is 30, Sophia is 21, and David is 60. Along comes a kidney with a KDPI of 10%. Since Mary and Sophia have better estimated survival than David (EPTS, 19%, 12%, and 75% respectively; again, it’s the percentile, so lower is better), they would have priority for that kidney.
However, if the available kidney has a KDPI of, say, 40%, age becomes a bigger factor. If the donor is 34, Mary and Sophia continue to have priority over David, since recipients ages 19 to 49 would be considered first. If the donor is 55, however, David would have precedence over Mary and Sophia, since the age range for that kidney recipient would be 40 to 70.
All of this can be confusing, and it leads one to suspect that some of the news entities who misspoke either did not understand what they were reading or perhaps did not even finish reading the report. But these components do not even tell the entire story; they are exactly that, components. The final proposal, which will be written only when all the feedback from a public comment period has been compiled and analyzed, “will include all the details of who gets the kidney,” as Friedewald says.
What is important to know now is that “waiting time will continue to be a major part of who gets a kidney” if the revised allocation concepts become policy, Friedewald emphasizes. “What this document says is that we’re generally going to group people based on the quality of the donor kidney. But once we do that—let’s say it’s a top 20% kidney—well, then the top 20% of candidates who are expected to live the longest will be up for that kidney. But that may be 10,000 people. Which of the 10,000 people gets the kidney? The person who waits the longest.”
Besides making better use of the available kidneys, the revised allocation system would also make use of more kidneys, by eliminating the previous designation of “expanded criteria donor,” or ECD, kidneys. Some patients turn down ECD kidneys when they are offered, because they may consider the designation a kind of stigma.
“People think ‘expanded criteria’ is this horrible kidney that came from someone who was very old or who probably drank his whole life or had HIV and hepatitis B,” Weis Malone says. “But it could be a 55-year-old person who was taking one blood pressure medication. Right now, there is something like a 12% waste of kidneys that are just being thrown away. As the transplant list grows, it would be nice to utilize those kidneys.”
Obviously, no one would object to someone turning down a kidney from, say, a known IV drug user who was testing negative at the time of death. But does it make sense for a 70-year-old man to turn down an ECD kidney with a creatine level of 1.3, indicative of slight kidney damage? “When you’re talking about someone who has all kidney damage,” Zuber says, “you want to say, ‘What are you thinking? You don’t need a perfect kidney; you need a kidney.’”
Two other provisos: The revised allocation criteria do not affect persons waiting for a multiple-organ transplant (such as kidney/pancreas, kidney/heart, or kidney/liver). They also would apply to the adult (18 and older) population; pediatric candidates would continue to have priority, because as Zuber says, “If you don’t transplant a child, they will lose growth. It makes a huge difference when you’re a child, whereas when you’re an adult, it doesn’t matter if you’re 20 or 50.”
Focus on Prevention, Solutions
As indicated above, Concepts for Kidney Allocation is the latest step in the process of revising how kidneys are allocated. The Kidney Transplantation Committee will assess the feedback it receives, determine if there is a consensus, then issue a final proposal. UNOS and the Health Resources and Services Administration will be the groups that vote on whether to adopt the recommendations as policy.
In the meantime, other aspects of kidney allocation and transplantation will continue to be discussed and debated, whether officially or among the general public. Among the questions: How can the pool of living donors be increased? Should the US adopt a “presumed consent” policy that would require people to expressly opt out of organ donation? What other methods might increase donations—better education, payment of funeral expenses for the deceased donor, or something as yet undetermined?
For nephrology clinicians, the goal remains keeping people alive while they await transplantation. “Even when I’m doing a perfect job—that’s a perfect job, and at few times in my life am I perfect—I am no better than 15% of a kidney,” Zuber says of her dialysis work. At the same time, it must be accepted that even transplantation is “not a cure,” as Weis Malone points out. “It’s a treatment, just like dialysis is a treatment. Not everyone does well with it.”
For Weis Malone, “the focus always needs to be on the prevention of kidney disease, especially as diabetes continues to grow massively in this country. Probably 30% to 40% of people who start dialysis had no idea they had kidney disease. So that’s where it has to start, with the education of the medical community that the only way you can tell kidney function is through a blood test or a urine dip.”
And the search for solutions to the growing problem of kidney disease, and subsequent kidney failure, will continue. “This is what the public debate is about: what is acceptable,” Friedewald says. “There is no right or wrong here. But what is acceptable, and what kind of trade-offs are we willing to make to get more out of a scarce resource?”