Retroactive application of the new kidney allocation system to renal transplants performed in the ECD / SCD era

The kidney allocation system ( KAS ) aims to improve deceased donor kidney transplant outcomes by matching of donor allografts and kidney recipients using the kidney donor risk index ( KDRI ) and recipient estimated post‐transplant survival ( EPTS ) indices. In this single‐center study, KAS was retroactively applied to 573 adult deceased donor kidney transplants (2004–2012) performed in the extended criteria/standard criteria donor ( ECD / SCD ) era. Donor KDRI and recipient EPTS were calculated, and transplants were analyzed to identify KAS fits. These were defined as allocation of top 20% allografts to top 20% recipients and bottom 80% allografts to bottom 80% recipients. On retroactive calculation, 70.2% of all transplants fit the KAS . Transplants that fit the KAS had inferior 1‐ and 5‐yr patient survival (95.5% vs. 98.8%, p = 0.048, and 83.4% vs. 91.7%, p = 0.018) and similar 1‐ and 5‐yr graft survival compared to transplants that did not fit the KAS (91.3% vs. 94.1%, p = 0.276, and 72.7% vs. 73.9%, p = 0.561). While EPTS correlated with recipient survival ( HR = 2.96, p < 0.001), KDRI correlated with both recipient ( HR = 3.56, p < 0.001) and graft survival ( HR = 3.23, p < 0.001). Overall, retroactive application of the KAS to transplants performed in the ECD / SCD era did not identify superior patient survival for kidneys allocated in accordance with the KAS .