Background & aims: The National Liver Offering Scheme (NLOS) was introduced in the UK in 2018 to offer livers from deceased donors to patients on the national waiting list based, for most patients, on calculated transplant benefit. Before NLOS, livers were offered to transplant centres by geographic donor zones and, within centres, by estimated recipient need for a transplant.
Methods: UK Transplant Registry data on patient registrations and transplants were analysed to build survival on the list (M1) and survival post-transplantation (M2) statistical models. A separate cohort of registrations - not seen by the models before - was analysed to simulate what liver allocation would have been under M1, M2 and a Transplant Benefit Score (TBS) model (combining both M1 and M2), and to compare these allocations to what had been recorded in the Registry. Number of deaths on the waiting list and patient life years were used to compare the different simulation scenarios and to select the optimal allocation model. Registry data were monitored, pre- and post-NLOS, to understand the performance of the scheme.
Results: The TBS was identified as the optimal model to offer livers from donors after brain death (DBD) to adult and large paediatric elective recipients and, in the first two years of NLOS, 68% of DBD livers were offered using the TBS to this type of recipient. Monitoring data indicate that mortality on the waiting list post-NLOS significantly decreased compared with pre-NLOS (p<0.0001), and that patient survival post-listing is significantly greater post-than pre-NLOS (p=0.005).
Conclusions: In the first two years of NLOS offering, waiting list mortality fell while post-transplant survival was not negatively impacted, delivering on the scheme's objectives.
Impact and implications: The National Liver Offering Scheme (NLOS) was introduced in the UK in 2018 to increase transparency of the deceased donor liver offering process, maximise the overall survival of the waiting list population, and improve equity of access to liver transplantation. To our knowledge, it is the first scheme that offers organs based on statistical prediction of transplant benefit; the Transplant Benefit Score (TBS). The results are important to the transplant community - from healthcare practitioners to patients - and demonstrate that, in the first two years of NLOS offering, waiting-list mortality fell while post-transplant survival was not negatively impacted, thus delivering on the scheme's objectives. The scheme continues to be monitored to ensure that the TBS remains up-to-date and that signals that suggest the possible disadvantage of some patients are investigated.
Keywords: Equity of access; Liver transplantation; Organ donation after brain death; Organ donation after circulatory death; Organ offering and allocation; Transplant benefit; survival on the waiting list; survival post-transplantation.
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