Best allograft survival from share-35 kidney donors occurs in middlE-Aged adults and young childreN - An analysis of OPTN data

BACKGROUND: On October 2005, the Organ Procurement and Transplant Network implemented a new allocation policy for kidney transplants (KTX) from deceased donors (DD) ages <35 years to increase an access to transplantation from young donors for pediatric (ages <18 years) recipients, which is known as Share-35 (S35). However, many of these kidneys were allocated to adult recipients. The intent of this study was to analyze the graft outcomes from S35 kidneys in pediatric and adult recipients, stratified further by recipient age, to assess if recipient age affects the outcome from these presumably ideal kidneys. METHODS: The Organ Procurement and Transplant Network database from October 2005 to November 2010 involving 18,461 S35-KTX was used to calculate cumulative graft survival (CGS), death-censored graft survival, and patient survival using Kaplan-Meier estimates. The differences between survival curves were tested for significance by log-rank method after adjusting for various donor, recipient, and transplant-associated variables. RESULTS: With S35 implementation, children received a higher proportion of DD ages <35 years. Within the pediatric age group, adolescents (ages 13-17 years) had the worst CGS. Among adults, the highest CGS was obtained in middle-aged adults, whereas young adults (ages 18-25 years) showed worse CGS. CGS in young children (ages <12 years) was comparable with those in middle-aged adults. In older adults (ages >55 years), CGS was lowered by higher patient death rates. CONCLUSIONS: Recipient age affects allograft survival from high-quality young DD kidneys, such as S35 kidneys. Best survival occurs in middle-aged adults and in children ages <12 years, whereas adolescents and young adults do not derive an optimal benefit.