ABO- or HLA- Incompatible LDKT Compared to Waitlist/DDKT in Elderly Patients

Overview

This retrospective multicenter cohort study evaluates the survival outcomes of elderly patients (aged ≥60 years) with end-stage kidney disease who underwent ABO- or HLA-incompatible living donor kidney transplantation compared with those managed with a conventional waitlisting strategy, including deceased donor kidney transplantation or remaining on the waiting list. Elderly patients often experience prolonged waiting times for deceased donor transplantation, during which dialysis-related complications may increase the risk of morbidity and mortality. Desensitization protocols have enabled transplantation across immunologic barriers, such as ABO or HLA incompatibility, potentially allowing earlier access to transplantation. Using data from two Korean transplant centers, this study compares overall survival and transplant-related outcomes between patients undergoing desensitized living donor transplantation and those managed with a waitlist-initiated strategy. The objective is to determine whether desensitized living donor kidney transplantation provides a survival advantage and represents a safe and effective treatment option for elderly patients.

This retrospective multicenter cohort study was conducted at Severance Hospital and Seoul National University Hospital between November 2010 and December 2023. The study included patients aged 60 years or older who initiated dialysis and were registered on the kidney transplant waiting list. Patients were categorized into two groups: The desensitized living donor kidney transplantation (LDKT) group, which included recipients of ABO-incompatible (ABOi), HLA-incompatible (HLAi), or combined ABOi/HLAi transplantation following desensitization therapy. The conventional waitlisting strategy (CWS) group, defined as patients managed with a standard waitlisting approach who either underwent deceased donor kidney transplantation (DDKT) during follow-up or remained on the waiting list. Immunologic assessment included ABO blood typing, isoagglutinin titers, flow cytometry crossmatch testing, and detection of donor-specific antibodies using single-antigen bead assays. Desensitization protocols consisted of rituximab administration, plasmapheresis with or without intravenous immunoglobulin, and risk-adapted induction therapy using basiliximab or anti-thymocyte globulin. Maintenance immunosuppression included tacrolimus, mycophenolate mofetil, and corticosteroids. To minimize selection bias, propensity score matching was performed to balance baseline characteristics between groups. Time-dependent Cox proportional hazards models were applied to account for immortal time bias related to pretransplant waiting periods. Transplantation (LDKT or DDKT) was treated as a time-dependent exposure in survival analyses. The primary outcome was overall patient survival. Secondary outcomes included graft survival and biopsy-proven acute rejection. Subgroup analyses were performed according to immunologic incompatibility (ABOi only, HLAi only, or combined ABOi/HLAi). This study aims to determine whether desensitized living donor kidney transplantation provides a survival benefit compared with a conventional waitlisting strategy in elderly patients with end-stage kidney disease.