Organ allocation revision struggles to balance justice and utility for kidney transplants
Kidney failure is a growing problem worldwide, in the United States and indeed right here in Nebraska. Prior to the invention of dialysis, kidney failure was uniformly lethal. But as dialysis techniques have evolved since the 1960s, many people now survive for years after their kidneys fail. In fact, according to the United States Renal Data System, there were more than 350,000 Americans receiving dialysis at the end of 2006.
But dialysis is by no means a solution. It is time-consuming and intrusive on patients’ lives, making it difficult to work and travel. Symptoms of kidney disease, such as fatigue and itching, often persist despite therapy. Dialysis treatments themselves may cause nausea, muscle cramps and low blood pressure. Infection, bleeding complications and fluid overload are constant threats and result in multiple hospitalizations for patients receiving maintenance dialysis. Finally, life expectancy is dramatically lower for people receiving dialysis compared to the general population.
The first successful kidney transplant was performed in Boston in 1954. Over the following four decades, there was intense research in the field of organ transplantation, including the development of better surgical techniques and better medications to prevent rejection of the implanted kidney by the recipient’s immune system. By the 1990s, it had become clear that kidney transplantation was the treatment of choice for end-stage kidney disease. It has been convincingly shown to prolong survival and improve the quality of life compared to remaining on dialysis.
It is no surprise, then, that the number of kidney transplants has increased steadily over time. There are more and more people afflicted with kidney failure, and the evidence is unquestioned that transplantation is the best treatment available. But the supply of kidneys, whether from living or deceased donors, is not able to keep pace with the ever-increasing demand. Thus, despite more than 16,000 kidney transplants being performed in the U.S. annually, there are currently more than 80,000 patients waiting for one, a gap that widens with every passing day.
There are 212 hospitals in the United States that have kidney-transplant programs. People with kidney failure are referred by their nephrologists to a transplant center, commonly the one that is closest to where they live. Transplant centers have teams of specialists that include surgeons, nephrologists, psychologists, social workers, dieticians, financial counselors and nurses, all of whom play an active role in the process.
The transplant evaluation is aimed at assessing the potential risks and benefits of transplantation for each individual, from the medical, surgical, psychological, social and financial points of view. A number of tests are typically performed as part of this process, including cardiac stress testing, CAT scans of the abdomen, age-appropriate cancer screening and blood tests for viral hepatitis.
Based on this evaluation, the team decides whether they feel the patient is an appropriate candidate for transplantation. If the team’s opinion is that transplantation is likely to benefit the patient, living donors are usually sought. If none are available, the candidate is listed to await a kidney from a deceased donor.
The wait lists for various solid organ transplants are managed by the United Network for Organ Sharing (UNOS) by contract from the Department of Health and Human Services (HHS) as part of the Organ Procurement and Transplantation Network (OPTN). Lists for other organ transplants, such as hearts, lungs and livers, are based on medical urgency, judged by objective medical criteria. But a candidate’s position on the kidney wait list is primarily dictated by how long he or she has been on the list. Thus, when a kidney becomes available, it does not go to the sickest candidate or to the one who may benefit the most, but rather it goes to the person who has spent the most time waiting.
As organs for transplantation are such a scarce resource, their allocation has been the subject of intense scrutiny—scrutiny that has led to recent revisions of both the liver and lung allocation schemes. The current system for determining which candidate will receive a given kidney has been in place for more than 20 years, with surprisingly few modifications over time. This may be about to change: UNOS has been reviewing this issue since 2004, and revision of the system for allocating kidneys from deceased donors seems likely in the near future.
Two facts are of central concern, based on a UNOS committee review. First, the most common cause for transplanted kidneys to fail is that the recipient dies with the organ still functioning. Second, the number of people with a failed transplant that need a second is increasing.
Taken together, it is apparent that donors and recipients are not well matched, such that kidneys expected to work for a long time can (and do) end up in patients with short life expectancy. At the same time, the current system allows patients with long expected survival (frequently younger, with fewer co-existing medical problems) to receive kidneys of relatively poor quality, practically guaranteeing that they will need a repeat transplant down the road.
Other criticisms of the existing system include concern about geographic disparity in access to transplantation: Average wait times in California, for instance, are more than double those for patients listed in Nebraska. There are also unacceptable differences in transplant rates by race. The algorithm is also inefficient, in that contact often needs to be made with multiple centers before an organ offer is accepted.
The time it takes to make these calls adds up and can result in poorer performance of the organ once transplanted. Finally, the system is complex,and can be confusing to patients and transplant professionals alike. The “point system” is dominated by length of time spent waiting, but there are myriad caveats and exceptions, making it nearly impossible to predict, even roughly, when a given patient should expect to get called in for a kidney.
The review of this issue began with reiteration of the overall mission for solid organ transplantation. In 2000, under the OPTN “Final Rule,” HHS had stated that any allocation system be based on “sound medical judgment,” seek “to achieve the best use of donated organs” and be designed “to avoid wasting organs” and “futile transplants.” Thus, the reviewing committee was charged with balancing the ethical concepts of justice and utility for distribution of this scarce resource. In short, the system needed to be fair and efficient.
So, after four years of deliberation, the OPTN’s Kidney Transplant Committee unveiled a new algorithm for the allocation of deceased-donor kidneys. Its roots were from statistical modeling of outcomes of patients and kidneys that have been meticulously tracked for decades.
Statisticians furnished lists of objective, easily obtainable criteria that can help estimate both the quality of a donated kidney and the life expectancy of a given recipient. They proposed an algorithm combining these estimates with the goal of matching donor to recipient to make optimal use of organs in short supply.
The phrase “Life Years From Transplant” (LYFT) was coined to represent the estimated survival advantage for a patient receiving a kidney transplant. This became the metric of transplant utility. Under this scheme, the concept of first-come, first-served was to be all but eliminated. The field seemed poised to take a major step in a new direction.
However, at a public forum in St. Louis in January of 2009, the progress toward a revised allocation scheme was brought to a screeching halt. Attendees included transplant physicians and surgeons, administrators, patients, patients’ family members and representatives from the several major kidney disease advocacy groups. At that meeting, there was widespread opposition to the proposed revision, and the ultimate result was that the entire plan has been tabled by the OPTN, in essence, to begin again.
Interestingly, the major focus of the criticism surrounded the issue of patient age. It is a well-known (though often understated) fact that older people are more likely to die than younger people. Hence, when the statistical models for transplant benefit are scrutinized, what they show is that the dominant force driving post-transplant survival is, no surprise, age of the recipient.
To maximize the utility of a good quality (i.e., young) kidney, it needs to be transplanted into a young candidate, at least under the proposed scheme. Now one can see how utility comes in direct conflict with justice: In an effort to “to achieve the best use of donated organs,” “avoid wasting organs” and avoid “futile transplants,” the committee had invented an algorithm that shunted good kidneys to young candidates and bad kidneys to older candidates.
Realization of this did not sit well with those in attendance in St. Louis, and the scientific journals have been riddled with editorials on the topic as well. In the end, the perceived injustice of the proposed system led to it being abandoned.
Where do we go from here? Back to the proverbial drawing board. The efforts of the committee were by no means wasted, as considerable knowledge has been gained about the quality and use of the existing data. Perhaps even more valuable was that the process forced people across the breadth of this field to discuss very difficult ethical concepts that will help frame the path forward.
In the meantime, patients will continue to be referred to centers for evaluation and placed on the list if deemed candidates. They will continue to get dialysis until getting a call that a kidney is coming in for them. It will still seem like a long time to wait for the gift of life. A new allocation system is coming, though its arrival now appears delayed indefinitely. When it arrives, though, it promises to be more predictable, more transparent, more efficient and, hopefully, will achieve a more acceptable balance between justice and utility.
Delicious
Digg
StumbleUpon
Facebook
Yahoo
Post new comment