P CLAYTON1,2,3, M SYPEK1,4, A GULYANI1,3, J KANELLIS5, S MCDONALD1,2,3
1Australia and New Zealand Dialysis And Transplant (ANZDATA) Registry, Adelaide, Australia, 2Central Northern Adelaide Renal and Transplantation Service, Royal Adelaide Hospital, Adelaide, Australia, 3University of Adelaide, Adelaide, Australia, 4University of Melbourne, Melbourne, Australia, 5Renal Unit, Monash Medical Centre, Clayton, Australia
Aim: To simulate restricting the allocation of low-risk kidneys to recipients with favourable prognoses.
Background: The Australian deceased donor kidney allocation system does not attempt to match the prognosis of kidneys and recipients, leading in some instances to low-risk kidneys (with a high projected graft survival) being allocated to high-risk recipients (with a limited life expectancy).
Methods: We constructed an event-based simulation model by adapting the US Kidney-Pancreas Simulated Allocation Model software to the Australian context. We simulated the current allocation system over 2010-2014 (5,362 patients, 2,833 kidneys), and two alternative models: (1) low-risk kidneys (lowest 20% kidney donor risk index) restricted to non-high-risk recipients (lowest 80% estimated post-transplant survival score [EPTS]), (2) low-risk kidneys restricted to low-risk recipients (lowest 20% EPTS). In each alternative model national sharing for immunological advantage was preserved, and simulations used either the Australian EPTS (incorporating age, waiting time and prior transplantation) or the original US EPTS (additionally incorporating diabetes). Outcomes were the distribution of low-risk kidneys and overall projected life-years.
Results: The characteristics of low-risk kidney recipients were similar when comparing model 1 and the current allocation system, with the exception of less waiting time. In model 2, these kidneys were allocated to younger patients with less waiting time and fewer comorbidities. Overall projected life-years were 86,735 in the current system; 86,842 in model 1 and 87,411 in model 2 using the Australian EPTS; and 87,078 in model 1 and 87,732 in model 2 using the US EPTS.
Conclusions: Avoiding allocating low-risk kidneys to high-risk recipients made only a negligible difference; restricting their allocation to low-risk recipients made more difference to organ distribution but overall life-years gained remained modest.
Dr Clayton is a nephrologist at the Royal Adelaide Hospital and serves on the executive of the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry.