This article is part of a series on Health Policy. See also:
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- Hospital Salaries Could Cut Care Costs
- The Appropriate Practice Scope of Chiropractic May Be a Political Question, Not a Scientific One
The United Network for Organ Sharing (UNOS) runs the nationwide waiting list for donor kidneys. 100,000 Americans currently sit on this list; unfortunately, 50% will die before a kidney arrives, as wait times can exceed 10 years. Further, since the number of recipients is growing faster than the number of donors, the wait time, and consequently the mortality rate, can only be expected to increase. (1)
But there’s hope! Recent updates to the UNOS donor kidney allocation policy might drastically reduce wait times.
UNOS policy revisions
Since its establishment 25 years ago, the UNOS waiting list has worked on a first-come, first-served basis. Of course, factors like blood type and organ size are considered. (4) Besides these, though, priority is granted solely based on the order in which recipients sign up for the list. While this policy underscores fairness, it comes with great drawbacks. Age of the donor and recipient are not considered, which means that a young, healthy kidney from a 30-year-old donor might easily end up in a recipient with only a few years left to live. Thus many life-years are wasted. Worse, the reverse scenario might occur. Chances are that a 30-year-old recipient of an old, worn-out kidney will end up back on the list again, further increasing wait times. The first-come, first-served system is fair, but it sacrifices efficiency. (2)
Just a few months ago, the UNOS approved sweeping changes to its allocation policy. One of these changes was that the 20% of kidneys expected to last the longest would be reserved for those 20% of recipients expected to live the longest following the transplant. These changes will be implemented sometime in 2014. (3)
I’m not satisfied, though. The 30-year-old might not receive a 70-year-old kidney, but the 40-year-old might. Experts agree. “You haven’t given an ethical justification for why you’re going to create this top 20 percent,” says Lainie Friedman Ross, a bioethicist at the University of Chicago. (2) The problem is lessened, but only slightly, and now a different age group bears the worst of the burden. Why stop at the top 20%? Why not reserve the 20%-40% healthiest organs for the 20-40% youngest recipients, and so on?
Dynamic allocation policy programming
Harvard Business School professor Nikolaos Trichakis studies methods for efficient air traffic control. In a purely-fair system, the first plane to land on the runway is the first to take off. However, once again, fairness precludes efficiency. One plane, slotted near the front of the line, sends its passengers toward a four-hour layover. Meanwhile, another plane sits at the back of the line as its passengers miss a tight connection. A simple swap would have allowed a successful trip for all parties.
Upon hearing of the proposed UNOS update, Trichakis wasn’t satisfied either. So he developed a matching algorithm that includes “life-years” as one of its components, as well as criteria for physiological compatibility and fairness. Using decades of past medical data, he input the same restrictions we use today, and then allowed the program to compute optimal parameters for maximization of life-years, using algorithms similar to those in Ben’s stock performance optimizer. Trichakis’s system provided an 8% increase in life-years, even with standard fairness restrictions! This would undoubtedly exceed the effect of UNOS’s 20% system. And by relaxing fairness constraints, projected life-years increased by as much as 30%. (5) Trichakis is currently working with doctors to learn the specifics of organ allocation and distribution, so as to further improve and hopefully implement his procedure. (6)
Trichakis’s 8% is a no-brainer, since fairness isn’t sacrificed. What about his 30%? Here, more interesting questions arise.
Let’s talk a little more about the fairness constraint. For one, fairness prioritizes those who have been waiting longer. Also, the constraint prioritizes certain physiological traits: each recipient possesses certain traits that might facilitate or obstruct donor matching. For example, the O blood type is the universal donor, so type-O patients can only receive transplants from like patients. Meanwhile, AB is the universal recipient. So, a type-AB patient will have a much easier time finding matches. Patients’ natural immune response varies as well. A patient with a sensitive immune system will be more likely to reject a kidney, and thus can only accept kidneys containing very low levels of potentially-dangerous antigens. The fairness constraint gives priority to type-O and immunosensitive patients so that no patient is denied access to donor organs because of inherent physiology. (5)
We could increase life years from 8% to a huge 30% if we simply told type-O and immunosensitive patients “tough.” Some patients would die, but many would live much longer! In the end, isn’t “life-years” what matters? However, such a decision would be unconscionable. Why? Well, it seems wrong to penalize A for conditions outside his control, even if that penalty might extend the life of B. Hold on a second, though: isn’t B now penalized instead? A’s remaining years rises from 0 to 5, while B’s drops from 30 to 20. And it’s outside of B’s control that A exists in the first place!
At the same time, it seems more heinous to directly end A’s life than to indirectly shorten B’s. Deontological ethics seem to be at play here. One could even argue that A needs those 5 years more than B needs his 10. Even 1 year—even just a day—would allow for final goodbyes and reflections. “Isn’t one moment of bliss sufficient for the whole of a man’s life?”
The 8 vs 30 debate can rage on, but for now, let’s at least choose 8! UNOS’s policy amendments are a great step in the right direction, but as long as more can be done, it should. We may refuse to yield to slackened fairness constraints, but let’s at least recognize the power of bioinformatics.
- Bioethics and Transplantation: Who Has a Kidney?
- Who’s Next In Line For A Kidney Transplant? The Answer Is Changing
- Public comment sought on proposed revisions to deceased donor kidney allocation policy
- Arthur Caplan’s piece on Organ Transplantation from From Birth to Death and Bench to Clinic: The Hastings Center Bioethics Briefing Book for Journalists, Policymakers, and Campaigns
- Fairness, Efficiency and Flexibility in Organ Allocation for Kidney Transplantation by Nikolaus Trichakis
- What Air Traffic Can Teach Us About Kidney Transplants featuring mention of Trichakis