At any time, around 100,000 people in the US are waiting to become kidney transplant recipients. About a fifth of them get a new kidney each year, but others die while waiting. In short, kidney demand is important to consider how limited supply is used.
A study co-authored by MIT economists brings new data to this issue and provides subtle estimates of the lifespan extension effects of kidney transplants. While it may be difficult to measure well, this study is the first to explain some of the complexities involved, including some of the decisions patients make when accepting kidney transplants and some of the existing health factors.
This study concludes that the system in use produces an additional 9.29 lifespan from kidney recipient implantation (LYFT). (Lyft is the difference in median survival with or without implants.) If organs are randomly assigned to patients, the study finds that the Lyft mean is only 7.54 overall. From that perspective, the current implantation system is net positive for patients. However, this study found that Lyft's number could potentially be increased to 14.08 depending on the structure of the match system.
In any case, more accurate estimates of the benefits of kidney transplants can help inform policy makers about the dynamics of the matching system in use.
“There's always this question about how to efficiently and successfully place the number of organs being donated because they lack the number of donated organs,” says MIT economist Nikhil Agarwal, co-author of a newly published paper detailing the findings of the study. As he emphasizes, the point of the paper is not to advocate a certain perspective, but to inform the ongoing improvements of the system of coincidence.
paper,”Choice of allocation mechanisms and consequences: Assigning deceased donor kidneysis featured in the latest issue Econometrica. The author is Agarwal, a professor at MIT's Faculty of Economics. Charles Hodgson, assistant professor of economics at Yale University. Paulo Somaini, an associate professor of economics at Stanford University's Graduate School of Business.
There is a period that lasts up to 48 hours after people die, where they can become viable organ donors. Potential kidney recipients are prioritized not only by histological similarity, but also by the amount of time spent on the waiting list, allowing them to accept or reject a particular transplant offer.
Over the past decade, Agarwal has conducted important empirical studies on organ donation, particularly the concordance system of kidney transplantation. To carry out this study, the researchers used comprehensive data on kidney waiting list patients from 2000 to 2010. This allowed scholars to analyze both the matching system and the health effects of implantation. They will track patient survival until February 2020.
This work is the first quasi-periodic study of kidney transplants. Careful examination of the decision-making trends of kidney recipients allows scholars, along with many other health factors, to assess the effects of transplants, and others are equal. Recipients are more likely to choose kidney offers from donors who are young, have a lack of hypertension, head trauma (suggesting that internal organs are healthy), and have a complete histological match.
” [previous] The methodology for estimating what life expectancy benefits were not to incorporate this problem of choice,” Agarwal says.
Furthermore, overall, an important empirical feature of kidney transplantation is that overall healthy recipients tend to provide the greatest realised annual benefits from transplantation. This means that the biggest increase in LYFT is not seen in a set of patients with the worst health conditions.
“You might think that the person most sick and most likely to die without organs will benefit most from it. [in added life-years]Agarwal says. “However, other comorbidities or factors may be sick and the body will be hit by a new organ, so the benefits may not be that great.”
With this in mind, the maximum Lyft number in this study 14.08 comes roughly from a hypothetical scenario where the number of otherwise healthy individuals increases. Again, the current system tends to prioritize time spent on waiting lists. And some observers may advocate for a system that prioritizes the most sick people. With all this in mind, the kidney transplant policy-making process may still include the recognition that the greatest benefits of a patient's life annual life are not necessarily consistent with other prioritization factors.
“Our results … show a dilemma rooted in tension between these two goals,” the author wrote in his paper.
To be clear, rather than defending one system over another, Agarwal conducts data-driven research to enable policymakers to make more informed decisions in the ongoing, long-term process of improving valuable port networks.
“Making ethical decisions isn't necessarily the advantage of my comparison, but at least I can think about some of the trade-offs and quantify them,” adds Agarwal.
Research support was provided in part by the National Science Foundation and the Alfred P. Sloan Foundation.
