Global kidney chains.

Kidney failure is a worldwide scourge, made more lethal by the shortage of transplants. We propose a way to organize kidney exchange chains internationally between middle-income countries with financial barriers to transplantation and high-income countries with many hard to match patients and patient-donor pairs facing lengthy dialysis. The proposal involves chains of exchange that begin in the middle-income country and end in the high-income country. We also propose a way of financing such chains using savings to US health care payers.

Popular repugnance contrasts with legal bans on controversial markets.

We study popular attitudes in Germany, Spain, the Philippines, and the United States toward three controversial markets-prostitution, surrogacy, and global kidney exchange (GKE). Of those markets, only prostitution is banned in the United States and the Philippines, and only prostitution is allowed in Germany and Spain. Unlike prostitution, majorities support legalization of surrogacy and GKE in all four countries. So, there is not a simple relation between public support for markets, or bans, and their legal and regulatory status. Because both markets and bans on markets require social support to work well, this sheds light on the prospects for effective regulation of controversial markets.

Non-simultaneous kidney exchange cycles in resource-restricted countries without non-directed donation - a prospective single-center cohort study.

Recent reports suggest that bridge-donor reneging is rare (1.5%) in non-simultaneous kidney exchange chains. However, in developing countries, the non-directed donors who would be needed to initiate chains are unavailable, and furthermore, limited surgical space and resources restrain the feasibility of simultaneous kidney exchange cycles. Therefore, the aim of this study was to evaluate the bridge-donor reneging rate during non-simultaneous kidney exchange cycles (NSKEC) in a prospective single-center cohort study (n = 67). We describe the protocol used to prepare co-registered donor-recipient pairs for non-simultaneous surgeries, in an effort to minimize the reneging rate. In addition, in order to protect any recipients who might be left vulnerable by this arrangement, we proposed the use of standard criteria deceased-donor kidneys to rectify the injustice in the event of any bridge-donor reneging. We report 17 successful NSKEC resulting in 67 living-donor kidney transplants (LDKT) using 23 bridge-donors without donor renege and no intervening pairs became unavailable. We propose that NSKEC could increase LDKT, especially for difficult-to-match sensitized pairs (25 of our 67 pairs) in countries with limited transplantation resources. Our study confirms that NSKEC can be safely performed with careful patient-donor selection and non-anonymous kidney exchanges.

Promoting Ethical Payment in Human Infection Challenge Studies.

To prepare for potential human infection challenge studies (HICS) involving SARS-CoV-2, we convened a multidisciplinary working group to address ethical questions regarding whether and how much SARS-CoV-2 HICS participants should be paid. Because the goals of paying HICS participants, as well as the relevant ethical concerns, are the same as those arising for other types of clinical research, the same basic framework for ethical payment can apply. This framework divides payment into reimbursement, compensation, and incentives, focusing on fairness and promoting adequate recruitment and retention as counterweights to concerns about undue inducement. Within the basic framework, several factors are especially salient for HICS, and for SARS-CoV-2 HICS in particular, including the nature of participant confinement, anticipated discomfort, risks and uncertainty, participant motivations, and trust. These factors are reflected in a payment worksheet created to help sponsors, researchers, and ethics reviewers systematically develop and assess ethically justifiable payment amounts.

The 6-year clinical outcomes for patients registered in a multiregional United States Kidney Paired Donation program - a retrospective study.

We examined what happened during a 6-year period to 1121 end-stage renal disease patients who registered with their willing/incompatible living donors for kidney exchanges with the Alliance for Paired Donation (APD). Of all patients, 65% were transplanted: 37% in kidney paired donation (APD-KPD, APD-other-KPD); 10% with compatible live donors (APD-LD); and 18% with deceased donors (APD-DD). The remaining patients were withdrawn (sick/died/others; 15%), or were still waiting (20%). For those patients with a cPRA 0-94%, 72% received a transplant. In contrast, only 49% of very highly sensitized (VHS; cPRA 95-100%) were transplanted. Of the VHS patients, 50% were transplanted by KPD/APD-LD while 50% benefited through prioritization of deceased donors in the modified kidney allocation system (KAS introduced in 2014). All APD transplanted groups had similar death-censored 4-year graft survivals as their relevant Organ Procurement and Transplantation Network (OPTN) groups. It is noteworthy that VHS graft and patient survival results were comparable to less sensitized and nonsensitized patients. All patients should be encouraged to search for compatible donors through different options. Expanding the donor pool through KPD and the new KAS of the OPTN increases the likelihood of transplantation for VHS patients.

Effect of match-run frequencies on the number of transplants and waiting times in kidney exchange.

Numerous kidney exchange (kidney paired donation [KPD]) registries in the United States have gradually shifted to high-frequency match-runs, raising the question of whether this harms the number of transplants. We conducted simulations using clinical data from 2 KPD registries-the Alliance for Paired Donation, which runs multihospital exchanges, and Methodist San Antonio, which runs single-center exchanges-to study how the frequency of match-runs impacts the number of transplants and the average waiting times. We simulate the options facing each of the 2 registries by repeated resampling from their historical pools of patient-donor pairs and nondirected donors, with arrival and departure rates corresponding to the historical data. We find that longer intervals between match-runs do not increase the total number of transplants, and that prioritizing highly sensitized patients is more effective than waiting longer between match-runs for transplanting highly sensitized patients. While we do not find that frequent match-runs result in fewer transplanted pairs, we do find that increasing arrival rates of new pairs improves both the fraction of transplanted pairs and waiting times.

Marketplaces, Markets, and Market Design.

Marketplaces are often small parts of large markets, and both markets and marketplaces come in many varieties. Market design seeks to understand what marketplaces must accomplish to enable different kinds of markets. Marketplaces can have varying degrees of success, and there can be marketplace failures. I'll discuss labor markets like the market for new economists, and also markets for new lawyers and doctors that have suffered from the unraveling of appointment dates to well before employment begins. Markets work best if they enjoy social support, but some markets are repugnant in the sense that some people think they should be banned, even though others want to participate in them. Laws banning such markets often contribute to the design of illegal black markets, and this raises new issues for market designers. I'll briefly discuss markets and black markets for narcotics, marijuana, sex, and surrogacy, and the design of markets for kidney transplants, in the face of widespread laws against (and broader repugnance for) compensating organ donors. I conclude with open questions and engineering challenges.

Finding long chains in kidney exchange using the traveling salesman problem.

As of May 2014 there were more than 100,000 patients on the waiting list for a kidney transplant from a deceased donor. Although the preferred treatment is a kidney transplant, every year there are fewer donors than new patients, so the wait for a transplant continues to grow. To address this shortage, kidney paired donation (KPD) programs allow patients with living but biologically incompatible donors to exchange donors through cycles or chains initiated by altruistic (nondirected) donors, thereby increasing the supply of kidneys in the system. In many KPD programs a centralized algorithm determines which exchanges will take place to maximize the total number of transplants performed. This optimization problem has proven challenging both in theory, because it is NP-hard, and in practice, because the algorithms previously used were unable to optimally search over all long chains. We give two new algorithms that use integer programming to optimally solve this problem, one of which is inspired by the techniques used to solve the traveling salesman problem. These algorithms provide the tools needed to find optimal solutions in practice.

Incentivizing Organ Donor Registrations with Organ Allocation Priority.

How donor organs are allocated for transplant can affect their scarcity. In 2008, Israel's Parliament passed an Organ Transplantation Law granting priority on organ donor waiting lists to individuals who had previously registered as organ donors. Beginning in November 2010, public awareness campaigns advertised the priority policy to the public. Since April 2012, priority has been added to the routine medical criteria in organ allocation decisions. We evaluate the introduction of priority for registered organ donors using Israeli data on organ donor registration from 1992 to 2013. We find that registrations increased when information about the priority law was made widely available. We find an even larger increase in registration rates in the 2 months leading up to a program deadline, after which priority would only be granted with a 3-year delay. We also find that the registration rate responds positively to public awareness campaigns, to the ease of registration (i.e. allowing for registering online and by phone) and to an election drive that included placing registration opportunities in central voting locations. Copyright © 2016 John Wiley & Sons, Ltd.

Maximization, learning, and economic behavior.

The rationality assumption that underlies mainstream economic theory has proved to be a useful approximation, despite the fact that systematic violations to its predictions can be found. That is, the assumption of rational behavior is useful in understanding the ways in which many successful economic institutions function, although it is also true that actual human behavior falls systematically short of perfect rationality. We consider a possible explanation of this apparent inconsistency, suggesting that mechanisms that rest on the rationality assumption are likely to be successful when they create an environment in which the behavior they try to facilitate leads to the best payoff for all agents on average, and most of the time. Review of basic learning research suggests that, under these conditions, people quickly learn to maximize expected return. This review also shows that there are many situations in which experience does not increase maximization. In many cases, experience leads people to underweight rare events. In addition, the current paper suggests that it is convenient to distinguish between two behavioral approaches to improve economic analyses. The first, and more conventional approach among behavioral economists and psychologists interested in judgment and decision making, highlights violations of the rational model and proposes descriptive models that capture these violations. The second approach studies human learning to clarify the conditions under which people quickly learn to maximize expected return. The current review highlights one set of conditions of this type and shows how the understanding of these conditions can facilitate market design.

Early vs Single Match in the Transition to Residency: Analysis Using NRMP Data From 2014 to 2021.

Background: An Early Result Acceptance Program (ERAP) has been proposed for obstetrics and gynecology (OB/GYN) to address challenges in the transition to residency. However, there are no available data-driven analyses on the effects of ERAP on the residency transition. Objective: We used National Resident Matching Program (NRMP) data to simulate the outcomes of ERAP and compare those to what occurred in the Match historically. Methods: We simulated ERAP outcomes in OB/GYN, using the de-identified applicant and program rank order lists from 2014 to 2021, and compared them to the actual NRMP Match outcomes. We report outcomes and sensitivity analyses and consider likely behavioral adaptations. Results: Fourteen percent of applicants receive a less preferred match under ERAP, while only 8% of applicants receive a more preferred match. Less preferred matches disproportionately affect DOs and international medical graduates (IMGs) compared to US MD seniors. Forty-one percent of programs fill with more preferred sets of applicants, while 24% fill with less preferred sets of applicants. Twelve percent of applicants and 52% of programs are in mutually dissatisfied applicant-program pairs (a pair in which both prefer each other to the match each received). Seventy percent of applicants who receive less preferred matches are part of a mutually dissatisfied pair. In 75% of programs with more preferred outcomes, at least one assigned applicant is part of a mutually dissatisfied pair. Conclusions: In this simulation, ERAP fills most OB/GYN positions, but many applicants and programs receive less preferred matches, and disparities increase for DOs and IMGs. ERAP creates mutually dissatisfied applicant-program pairs and problems for mixed-specialty couples, which provides incentives for gamesmanship.

Report From a Multidisciplinary Symposium on the Future of Living Kidney Donor Transplantation.

Virtually all clinicians agree that living donor renal transplantation is the optimal treatment for permanent loss of kidney function. Yet, living donor kidney transplantation has not grown in the United States for more than 2 decades. A virtual symposium gathered experts to examine this shortcoming and to stimulate and clarify issues salient to improving living donation. The ethical principles of rewarding kidney donors and the limits of altruism as the exclusive compelling stimulus for donation were emphasized. Concepts that donor incentives could save up to 40 000 lives annually and considerable taxpayer dollars were examined, and survey data confirmed voter support for donor compensation. Objections to rewarding donors were also presented. Living donor kidney exchanges and limited numbers of deceased donor kidneys were reviewed. Discussants found consensus that attempts to increase living donation should include removing artificial barriers in donor evaluation, expansion of living donor chains, affirming the safety of live kidney donation, and assurance that donors incur no expense. If the current legal and practice standards persist, living kidney donation will fail to achieve its true potential to save lives.