*Purpose: The new Kidney allocation system (nKAS) implemented for optimization of organ placement. Like other organ allocation systems, kidney has been redefined from donation service area (DSA) – “local allocation” to circles centered around donor hospital. Aim is to reduce disparity in access and create a more equitable distribution system. The aim of this study was to examine the impact of this new policy on post-transplant kidney outcomes.

*Methods: Scientific Registry of Transplant Recipients (SRTR) data files were obtained for transplants between March 1, 2019 to September 30, 2021 were used for analysis. Simultaneous transplant or listing, en-bloc, living donor, and recipients less than 18 years were excluded from the study. Transplants prior to March 15, 2021 were categorized as pre-allocation and subsequent transplants as post-allocation.

*Results: Total of 44,458 kidney recipients were included in the study, 34,132 pre-allocation and 10,326 post-allocation. Donor variables were similar, including KDPI, between the two groups. Kidney waiting list time saw a significant increase in time 487 pre-allocation vs 502 days post-allocation (p-value: 0.0075). Post-allocation the organ had to travel 121 vs 73 nautical miles to be transplanted (p-value: <0.0001). There was a significant increase in CIT under the new system (17.3 pre-allocation vs 19.5 hrs post-allocation; p-value: <0.0001) and an increase in delayed graft function as well (29.9% pre vs 32.6% post; p-value: 0.0001). Serum creatinine at discharge in post-allocation was 4.07 vs 3.55 (p-value: <0.0001). No significant difference in graft and recipient survival was noted at six months. Since implementation of nKAS another significant finding has been an increase in the kidney discard rate (23.4% vs 21.1%, p-value: <0.0001).

*Conclusions: The nKAS has improved access nationally for patients receiving kidney transplants with longer wait-times. However, nKAS has had potentially unintended negative impact on short-term outcomes. Further studies are needed to analyze if the increase in travel distances, CIT, and DGF rates will have an impact on both long-term outcomes and cost of kidney transplantation. With the continued organ shortage, it is imperative that we monitor and address the recent increase in discarded kidneys.

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