Supplementary Material for: Outcomes of ABO-incompatible living donor kidney transplantation compared to waiting or deceased donor kidney transplantation

Introduction: ABO-incompatible (ABOi) living donor kidney transplantation (LDKT) is considered only for patients who do not have an ABO-compatible (ABOc) LD. Therefore, a clinically practical question is whether to proceed with ABOi LDKT or remain on dialysis while waiting for ABOc deceased donor kidney transplantation (DDKT). However, this issue has not been addressed in Asian countries, where ABOi LDKT programs are more active than DDKT programs.
Methods: A total of 426 patients underwent ABOi-LDKT between 2010 and 2020 at Seoul National University Hospital and Severance Hospital, Korea. We compared outcomes between the ABOi-LDKT and the propensity-matched control groups (waiting-list-only group, n=1,278; waiting-list-or-ABOc-DDKT group, n=1,278).
Results: The ABOi-LDKT group showed a significantly better patient survival rate than the waiting-list-only group (P=0.001) and the waiting-list-or-ABOc-DDKT group (P=0.048). When the ABOi-LDKT group was categorized into a high-titer group (peak anti-ABO titer≥1:128) and a low-titer group (peak anti-ABO titer≤1:64), the low-titer group showed better patient survival rates than those of the waiting-list-or-ABOc-DDKT group (P=0.046) or the waiting-list-only group (P=0.004). In contrast, the high-titer ABOi-LDKT group showed no significant benefit in patient survival compared to the waiting-list-or-ABOc-DDKT group. Death-censored graft survival in the ABOi-LDKT group was not significantly different from that in the ABOc-DDKT group (P=0.563).
Conclusion: The ABOi-LDKT group has better outcomes than the waiting-list-or-ABOc-DDKT group in a country with a long waiting time.