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

Lundgren, Samuel LU (2023) LÄKM07 20222
MD Programme
Abstract
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... (More)
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. (Less)
Popular Abstract (Swedish)
Omkring 10% av Sveriges befolkning lider av kronisk njursjukdom. För de flesta
patienter med långt gången, så kallad terminal njursjukdom är njurtransplantation den
bästa behandlingen, både för patientens livskvalitet och ur ett hälsoekonomiskt
perspektiv. Många patienter som har en villig donator passar inte med denna på grund
av icke kompatibla blodgrupper eller för att de har antikroppar mot donatorns
vävnadstyp. Njurbytesprogram adresserar detta problem genom att låta sådana
inkompatibla par byta donatorer med varandra med målet att uppnå kompatibilitet inom
de nya paren. Då detta kan öka tillgången till levande donation har flera sådana
njurbytesprogram startats runt om i världen.
När man inom ett njurbytesprogram... (More)
Omkring 10% av Sveriges befolkning lider av kronisk njursjukdom. För de flesta
patienter med långt gången, så kallad terminal njursjukdom är njurtransplantation den
bästa behandlingen, både för patientens livskvalitet och ur ett hälsoekonomiskt
perspektiv. Många patienter som har en villig donator passar inte med denna på grund
av icke kompatibla blodgrupper eller för att de har antikroppar mot donatorns
vävnadstyp. Njurbytesprogram adresserar detta problem genom att låta sådana
inkompatibla par byta donatorer med varandra med målet att uppnå kompatibilitet inom
de nya paren. Då detta kan öka tillgången till levande donation har flera sådana
njurbytesprogram startats runt om i världen.
När man inom ett njurbytesprogram testar vilka par som potentiellt skulle kunna byta
donatorer kan ofta flera möjliga byten identifieras. Då vissa av dessa byten kan stå i
konflikt med varandra behöver man implementera regler för vilka byten som ska
prioriteras. Dessa regler skiljer sig åt mellan njurbytesprogram. Målet med denna studie
var att studera om, och vilka, av dessa regler som spelar roll för vilka patienter som blir
transplanterade. Genom att simulera grupper av patienter och donatorer, baserat på
riktig data, och därefter låta reglerna i det brittiska, spanska, skandinaviska och
nederländska programmet välja vilka utbyten som skulle utföras kunde detta studeras.
Det som kunde ses var att andelen av matchade patienter som var den samma mellan
alla program var i snitt ca 73% (något beroende av antal par). De skillnader som sågs
mellan program var i hur länge patienter väntat på transplantation, ålder, åldersskillnad
mellan donator och patient, hur sensitiserade patienterna var till andra vävnadstyper och
grad av skillnad mellan vävnadstyp hos patient och donator. Dessa skillnader blev mer
systematiska ju fler som ingick i dessa program.
Denna studie ämnar inte porträttera exakt hur njurbytesprogrammen presterar i sin
naturliga miljö, men resultaten ger anledning att tro att det finns skillnader i utfall
beroende på vilka prioriterinsregler de har. Då det finns få liknande studier och den
tillgängliga utfallsdata är begränsad påvisar detta behov av vidare forskning och att öka
standardiserad rapportering för att kunna jämföra program med varandra. (Less)
Please use this url to cite or link to this publication:
author
Lundgren, Samuel LU
supervisor
organization
alternative title
Prioriteringar i parvisa njurbyten - En simuleringsstudie om europeiska njurbytesprogram
course
LÄKM07 20222
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Kidney Exchange, Pairwise Kidney Exchange, KEP, Priority, ESRD, Kidney Transplantation
language
English
additional info
MATLAB-code can be shared upon request
id
9113763
date added to LUP
2023-05-03 14:59:46
date last changed
2023-05-03 14:59:46
@misc{9113763,
  abstract     = {{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.}},
  author       = {{Lundgren, Samuel}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Priorities in Pairwise Kidney Exchanges - A Simulation Study on European Kidney Exchange Programs}},
  year         = {{2023}},
}