Living-Unrelated Donors Yield Higher Graft Survival Rates than Parental Donors

Abstract

Living-unrelated donors (LURD) have been shown to yield kidney graft survival rates equivalent to that of related donors. Here, we show that in three diseases, LURDs supply grafts that survive at a higher rate than parental or offspring donors. We analyzed 111,643 first adult kidney transplants from the United Network for Organ Sharing database performed between 1991 and 2003 by Kaplan-Meier curves, log-rank tests, and Cox proportional hazard tests. Five-year kidney graft survival rates in patients receiving grafts from LURD, parental, and offspring donors were 75.4%, 74.3%, and 75.7% among patients with typical original diseases excluding three diseases. In focal glomerulosclerosis (FGS), the corresponding results were 87.4%, 70.1%, and 81.6%. In polycystic kidney disease (PC) rates were 86.4%, 78.6%, and 85.3%, and in diabetes mellitus (type 1 DM) rates were 75.9%, 69.8%, and 70.5%. Parental donors yielded significantly lower graft survival rates than LURDs in all three diseases. Although statistically significant differences were lost in the Cox tests, functional graft survival showed significantly lower graft survival rates from parental donors compared with LURDs, suggesting that donor age was a significant factor. If living donors are considered for kidney transplantation into patients with FGS, PC, or type 1 DM, grafts from LURD are preferred over parental and offspring donors. Although genetic susceptibility of parental and offspring donor grafts may be a factor, the simple donor age factor probably results in lower survival of parental donor grafts. Lower survival of offspring donor grafts may suggest genetic susceptibility because such donors were, in general, younger than in LURD grafts.