*Purpose: ABO type B and O recipients have increased difficulty identifying a compatible donor for living-donor kidney transplantation (LDKT), and are harder to match in incompatible kidney transplantation (IKT) registries due to a shortage of ABO-compatible donors. A2-incompatible (A2i) LDKT may increase access to LDKT for these patients. To better inform the living donor selection process, we sought to evaluate the association between A2i LDKT and graft and patient survival.

*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 LDKT. 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: We identified 304 LDKT recipients reported as A2i. One-year, 5-year and 10-year patient survival were 98%, 92%, and 79% among compatible LDKT recipients, and 99%, 93%, and 79% among A2i transplant recipients (p=0.5, Figure). Patient mortality was comparable between A2i and compatible LDKT recipients (wHR _0.650.89_1.22, p=0.5). There was evidence of increased risk to A2i recipients with regards to all-cause graft failure (wHR _1.011.30_1.67, p=0.04) and death-censored graft failure (wHR _1.161.60_2.20, p=0.004).

*Conclusions: A2i LDKT is associated with an increased risk of all-cause graft failure and death-censored graft failure when compared to compatible LDKT. A2i donor/recipient pairs should be counseled about the increased risk, and referred for KPD. Furthermore, KPD matching algorithms should take this increased risk into account.

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