Outcomes of single kidney transplantation from small pediatric donors aged <5 years: comparative analysis between pediatric and adult recipients

The use of kidneys from small pediatric donors (< 5 years) for single kidney transplantation (SKT) may expand the donor pool. In recent years, many national allocation policies have given priority to pediatric recipients. However, comparative studies involving pediatric and adult recipients of single kidney transplants from small pediatric donors are limited. All patients who underwent SKT from small pediatric donors aged < 5 years at our center between January 1, 2015 and June 30, 2024 were included in this study. The outcomes included graft survival, patient survival, and post-transplant complications, which were compared between pediatric and adult recipients. The patient cohort included 83 adult recipients and 55 pediatric recipients from 48 and 40 small pediatric donors (aged < 5 years), respectively. Three-year death-censored graft survival and patient survival in pediatric recipients were 81.7% and 100%, respectively, which were not significantly different from those in adult recipients (89.0% and 95.8%). The leading cause of graft loss was vascular thrombosis (6 cases), followed by rejection (5 cases). No significant differences were observed between pediatric and adult recipients regarding primary nonfunction, the incidence of proteinuria, vascular and urinary complications, or the cumulative incidence of acute rejection. However, adult recipients experienced a significantly higher incidence of delayed graft function than pediatric recipients. SKT from small pediatric donors achieved comparable outcomes in adult and pediatric recipients, validating that current policies prioritizing pediatric recipients are clinically appropriate. Addressing risks of vascular thrombosis and rejection may further improve outcomes.