Paediatric deceased donor kidney transplant in Australia: A 30‐year review—What have paediatric bonuses achieved and where to from here?

In this 30‐year national review, we describe trends in DD transplantation for paediatric recipients, assess the impact of paediatric allocation bonuses and identify outstanding areas of need for this population.


| BACKG ROU N D
ESKD is a rare diagnosis in the paediatric population but has profound consequences for the child and their family. 1 For most children with ESKD, kidney transplantation not only offers a survival benefit when compared with dialysis, 2 but also provides improved opportunities for growth, 3 development, 4 education and social interaction, 5 and a superior quality of life. 6 Recognizing the unique needs and potential benefits of transplantation for this population, many transplant programmes worldwide have specific deceased donor organ allocation rules aimed at prioritizing access to trans-plantationforchildrenwithESKD. 7,8 Widespread adoption of paediatric bonuses implies a broad international consensus on the value of positive discrimination in organ allocation of this population. A white paper produced by the OPTN/UNOSPaediatricTransplantationandEthicsCommitteesset out several philosophical justifications for paediatric priority including the prudential lifespan account, the principles of 'fair innings' and maximizing the minimum benefit to the least advantaged and utility considerations. 9 Children also have unique growth and neurodevelopmental needs that can be optimized through earlier access to transplantation, 3,4 and studies into community preferences in the allocation or deceased donor organs have consistently shown support for prioritizing younger recipients. [10][11][12] It is also important to consider potential unintended consequences of this prioritization in a system dependent on the availability of scarce organs. 13,14 Expedited access to deceased donor transplantation may negatively impact living donor transplant rates, affect donor selection or have detrimental effects for other populationsonthewaitinglist.TheimpactsoftheUSShare35programme also serve as an example of the potential for unintended consequenceswhenimplementingapriorityallocationsystem.Whilethis programme achieved its goal of improving access to deceased donor transplantationforpaediatriccandidates,theexpeditedaccesswas associated with a decline in living donor transplant rates and in-creaseinHLAmismatchesforthispopulation. 15 AllocationofdeceaseddonorkidneysinAustraliaisperformed according to a national protocol developed by the TSANZ and implemented by the OrganMatch system that includes both national sharing and local allocation among the five transplanting regions. 16 Inbrief,allkidneysarefirstallocatedthroughanationalprogramme thatprioritizeshighlysensitizedpatientsandwell-matchedkidneys andaddressessharingimbalancesbetweenregions.Organsarethen allocated within transplanting regions based on local algorithms that meannumberofHLAantigenmismatchesforpaediatricrecipientsofDDtransplants increased each decade (2.86 [1989-1998] to over 60 000 000 and scores in the jurisdictional systems range from 0 to over 50 000 000. 16 Therefore,thepaediatricbonusesdonotgive absolute priority to children, but rather give them a priority over adults   Forsurvivalanalysis,exposurewasdefinedasdecadeoftransplantation (1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018).Thesurvivalfunction was calculated using the Kaplan-Meier method. Differences weretestedusingthelog-ranktest.Graftsurvivalwasnotcensored for death, and survival statistics were unadjusted.

| Patient and graft survival
There was a significant improvement in both patient and graft

| DISCUSS ION
The optimal deceased donor kidney for a child with ESKD is one thatcanbeaccessedquicklytoavoidthemorbidityassociatedwith dialysis,hasthebestpossiblelong-termgraftsurvivalandreduces theriskofsensitizationtopreservefuturetransplantopportunities.
OuranalysisdemonstratesthatunderAustralia'scurrentpaediatric bonus system, children with ESKD received more timely access to higherqualitykidneysfromdeceaseddonorscomparedwithadult recipients; however, we highlight the need for better strategies to improvedonor-recipientHLAmatchingforpaediatricrecipients.

F I G U R E 4 Annualtransplantrateper100activepatient-years forpatientsonthedeceaseddonorkidneytransplantwaitinglistin Australia,2006-2018,byagegroup
Duetotheincrementalimplementationofpaediatricbonuses across national and regional allocation systems in Australia, and in light of informal priorities given to the population in some jurisdictions, it is challenging to determine the impacts of, or attribute causation for the observed trends to specific policy changes. with the potential recipient are prospectively entered into the allocation system as unacceptable antigens, and therefore, organs from donors with unfavourable HLA profiles will not be allocated to these patients. 36 Informal HLA epitope-based immunological assessment of deceased donor kidney offers in a number of other Australian paediatric transplanting centres has also been reported to theauthors.WiththewidespreadavailabilityofHLAmoleculartyping,epitope-basedorganallocationoffersthepotentialforamore granularmethodofimmunologicriskassessmentintransplantation; however, more clinical outcome data and feasibility studies are required before this can be implemented at a system wide level. 33,37,38 Deceased donation is an important pathway for children with

ThedatareportedherehavebeensuppliedbytheAustraliaandNew
ZealandDialysisandTransplantRegistry.Theinterpretationandreporting of these data are the responsibility of the authors and in no way should be seen as an official policy or interpretation of the AustraliaandNewZealandDialysisandTransplantRegistry.

CO N FLI C T O F I NTE R E S T
Theauthorsdeclarenoconflictsofinterest.

AUTH O R CO NTR I B UTI O N S
Matthew P Sypek was the primary author, participated in study design and performed data management, statistical analysis, Registry.