Summary

Every year, more than 6,000 organ transplantations are performed in the eight European countries that participate in Eurotransplant. Despite this, the persistent shortage of donor organs means that about 1,000 patients die annually while waiting for an organ transplantation.

Eurotransplant is responsible for offering the deceased-donor organs to the candidates who await a transplantation. To which patient Eurotransplant makes an offer is determined by allocation rules, which have been shaped by almost six decades of scientific, legal, and ethical discussions between Eurotransplant and the national competent authorities of the eight member countries. Eurotransplant has implemented these rules in allocation algorithms, which determine which candidates are eligible to receive an organ offer, and in what order they ought to be contacted.

A central goal of Eurotransplant’s allocation systems is that patients should have an equal opportunity of receiving a transplant. A first goal of this thesis is to study research questions relating to such equality of opportunity. Our results show there is room for improvement. For example, female patients on the liver waiting list are more likely to experience an adverse outcome than male patients. We link this disparity to the smaller body size of female transplantation candidates – and not sex itself, as is suggested by the existing literature. Similarly, kidney transplant candidates who are immunized face reduced access to transplantation under the current rules. This latter disadvantage persist even though Eurotransplant has implemented special mechanisms to support these groups.

One reason why such disadvantages persist is that Eurotransplant lacks the tools to quantify the impact of policy changes. This complicates discussions within Eurotransplant’s advisory committees on how the allocation can be improved. To overcome this barrier, the second goal of this thesis is to develop discrete-event simulators for liver and kidney allocation. These tools allow Eurotransplant to assess the impact of alternative allocation policies on waiting list outcomes, and can facilitate collaborations with clinicians, policymakers, and other stakeholders on how allocation can be improved. We validated these simulation tools on historic data, and the simulators already support discussions within Eurotransplant on how policies can be improved. For example, the liver simulator has been used to support discussions on switching to a new score for liver allocation.

Although these tools do not eliminate the difficult ethical trade-offs involved in organ allocation, they help Eurotransplant by making these trade-offs explicit. Thereby, the simulators can pave the way for a more informed and constructive dialogue among clinicians, policymakers, and other stakeholders on how the allocation of deceased-donor organs can be improved.