Priorities in Pairwise Kidney Exchanges - A Simulation Study on European Kidney Exchange Programs

Sammanfattning: Background: For most patients with end stage renal disease (ESRD) kidney transplantation is the best treatment option. Best outcomes are achieved with living donation. To increase access to living donation for patients who are not compatible with their living donors, Kidney Exchange Programs (KEPs) have evolved. By exchanging donors, compatibility can be achieved thus enabling transplantation. In a so-called matching round many feasible, but conflicting, exchanges may be identified. Programs therefore implement rules for how to prioritize exchanges. The purpose of this study was to investigate how difference in priority rules between European KEPs affect which patients and donors are transplanted. Methods: A side-to-side comparison was done by running KEP matching rounds with simulated pairs, based on real patient and donor data, and the priority rules from the British, Spanish, Dutch, and Scandinavian program. The simulations were limited to pairwise exchanges within the blood group barrier. Results: With 150 pairs on average 51% were included in the matching round and of the matched recipients on average 72.6% were the same across programs. Significant differences were found in majority of the studied parameters. The British program seemed to match recipients with long waiting time, the Scandinavian those with higher cPRA (HLA immunization) and the Spanish younger recipients. These differences were clearer when increasing the patient pool. Conclusions: The conclusion of the study was that many priority rules in the current practices likely cause systematic differences in which patients are transplanted and these differences are likely accentuated when the size of programs increase. As few similar studies have been conducted and little outcome data is available this shows importance of further research, especially as the future improvement of KEP effectiveness partly rely on increasing number of participants and international collaborations.