Sunday, June 9, 2024

Recent kidney transplant papers

 Here are two new papers on kidney exchange that caught my eye, and one on incentivizing deceased donation by prioritizing registered donors on the deceased donor waiting list.

This one concerns organizing international kidney exchanges between countries while making sure that each one gets their fair share. (All exchanges are between 2 pairs.)

Benedek, Márton, Péter Biró, Daniel Paulusma, and Xin Ye. "Computing balanced solutions for large international kidney exchange schemes." Autonomous Agents and Multi-Agent Systems 38, no. 1 (2024): 1-41.

Abstract: To overcome incompatibility issues, kidney patients may swap their donors. In international kidney exchange programmes (IKEPs), countries merge their national patient–donor pools. We consider a recently introduced credit system. In each round, countries are given an initial “fair” allocation of the total number of kidney transplants. This allocation is adjusted by a credit function yielding a target allocation. The goal is to find a solution that approaches the target allocation as closely as possible, to ensure long-term stability of the international pool. As solutions, we use maximum matchings that lexicographically minimize the country deviations from the target allocation. We perform, for the first time, a computational study for a large number of countries. For the initial allocations we use two easy-to-compute solution concepts, the benefit value and the contribution value, and four classical but hard-to-compute concepts, the Shapley value, nucleolus, Banzhaf value and tau value. By using state-of-the-art software we show that the latter four concepts are now within reach for IKEPs of up to fifteen countries. Our experiments show that using lexicographically minimal maximum matchings instead of ones that only minimize the largest deviation from the target allocation (as previously done) may make an IKEP up to 54% more balanced.

"We consider IKEPs in the setting of European KEPs which are scheduled in rounds, typically once in every three months.


"We first note that the search for an optimal exchange scheme can be done in polynomial time for 2-way exchanges (matchings) but becomes NP-hard as soon as 3-way exchanges are permitted."


Here's a paper that reports simulations on Using deceased donor kidneys to start living donor kidney exchange chains

Verma, Utkarsh, Nayaran Rangaraj, Viswanath Billa, and Deepa Usulumarty. "Long term simulation analysis of deceased donor initiated chains in kidney exchange programs." Health Systems (2023): 1-12.

ABSTRACT: Kidney exchange programs (KEPs) aim to find compatible kidneys for recipients with incompatible donors. Patients without a living donor depend upon deceased donor (DD) donations to get a kidney transplant. In India, a DD donates kidneys directly to a DD wait-list. The idea of initiating an exchange chain starting from a DD kidney is proposed in a few articles (and executed in Italy in 2018), but no mathematical formulation has been given for this merger. We have introduced an integer programming formulation that creates DD-initiated chains, considering both paired exchange registry and DD allocations simultaneously and addressing the overlap issue between the exchange registry and DD wait-list as recipients can register for both registries independently. A long-term simulation study is done to analyse the gain of these DD-initiated chains over time. It suggests that even with small numbers of DDs, these chains can significantly increase potential transplants.


And here's the paper on incentivizing registration to be a deceased donor.

Li, Mengling, and Yohanes E. Riyanto. "Incentivizing Organ Donation Under Different Priority Rules: The Role of Information." Management Science (2024).

Abstract: This paper examines the incentive to register for deceased organ donation under alternative organ allocation priority rules, which may prioritize registered donors and/or patients with higher valuations for organ transplantation. Specifically, the donor priority rule grants higher priority on the organ waiting list to those who have previously registered as donors. The dual-incentive priority rules allocate organs based on donor status, followed by individual valuations within the same donor status, or vice versa. Both theoretical and experimental results suggest that the efficacy of the donor priority rule and the dual-incentive priority rules critically depends on the information environment. When organ transplantation valuations are unobservable prior to making donation decisions, the hybrid dual-incentive rules generate higher donation rates. In contrast, if valuations are observable, the dual-incentive priority rules create unbalanced incentives between high- and low-value agents, potentially undermining the efficacy of the hybrid dual-incentive rules in increasing overall donation rates.

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