Introduction: Simultaneous liver-kidney transplantation may confer an immunological advantage to the kidney graft. The aim of this study is to explore kidney graft outcomes following kidney versus simultaneous liver-kidney transplantation following the analysis of a large database.
Methods: Data were retrieved and analysed on kidney and combined liver-kidney transplants performed in pediatric recipients (younger than 18 years old) from October 1987 until September 2020, from the United Network for Organ Sharing (https://unos.org/). SPSS v28 was used for statistical analysis.
Results: There were 23597 kidney transplants (Group 1, 9628 female, median age 12, IQR 8) and 373 simultaneous liver-kidney transplants (Group 2, 183 female, median age 9, IQR 9). 10785 (45.7%) kidney grafts failed versus 109 (29.2%) kidneys from the simultaneous liver-kidney transplant group (P<0.001). Delayed graft function was present in 2068 (8.8%) in Group 1 and 70 (19%) in Group 2 (P<0.001). Primary non-function was 248 (1.1%) in Group 1 versus 7 (1.9%) in Group 2 (P=0.198). Kaplan-Meier Survival analysis showed a statistically significant difference between the two Groups (Log Rank of <0.001).

Conclusion: Delayed graft function is longer following simultaneous liver-kidney transplants. Despite this, simultaneous liver-kidney transplants have a better survival than kidney transplants alone. This may be due to the protective immunological effect of the liver transplant.