*Purpose: The Kidney Allocation System (KAS), implemented in 2014, increased offers of ABO type A2 donor kidneys to type O and B recipients, and A2B to B recipients (A2i). While previous studies showed no increased risk associated with A2I transplantation, these were studies of very highly selected patients with low sample size. It is important to understand if prior results are comparable to those of the post-KAS era to ensure the safety of patients undergoing this procedure.

*Methods: Using SRTR data 2000-2018, we identified adult, first-time kidney transplant recipients with blood type O or B who underwent ABO-compatible or A2i deceased donor kidney transplantation (DDKT). A2i was defined as using an A2 kidney for an O recipient or an A2 or A2B kidney for a B recipient. Inverse probability weighted Cox regression was used to compare post-transplantation mortality, all-cause graft failure, and death-censored graft failure between A2i and compatible recipients.

*Results: Out of 93703 recipients, 993 (1%) underwent A2i DDKT, of which 738 (74%) were post-KAS. One-year, 5-year, and 10-year patient survival were 96%, 84%, and 64% among compatible DDKT recipients and 96%, 87%, and 65% among A2i transplant recipients (p=0.6, Figure). Patient mortality was comparable between A2i and compatible DDKT recipients (wHR _0.700.92_1.22, p=0.6). There was no evidence of difference between A2i versus compatible DDKT recipients with regards to all-cause graft failure (wHR _0.881.12_1.44, p=0.3) and death-censored graft failure (wHR _0.951.27_1.72, p=0.1).

*Conclusions: Among almost 1000 A2i recipients across the United States, there is no evidence of harm resulting from prioritizing A2i DDKT in the KAS era.

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