Analysis of four scoring systems and monocentric experience to optimize criteria for marginal kidney transplantation

There is a strong need among the transplantation community to identify common criteria to utilize the pool of expanded criteria donors (ECD), considering the disparity between organ demand and supply as well as the benefits of transplantation on long-term mortality compared with survival on dialysis, also in patients transplanted with these organs. The purpose of this article was to analyze scoring systems proposed in literature by Nyberg, Anglicheau, Rao (Kidney Donor Risk Index), and Schold, seeking to verify whether our clinical and histological allocation strategy matched the Nyberg score. Herein we have reported the results of a preliminary retrospective study on the 5-year outcomes of organs from 60 marginal donors, who were older than 50 years and histologically evaluated before implantation. The donors matched Nyberg class C and D, that is, marginal donors. We noted a tendency toward an association between global and vascular scores with class D (odds ratio 2.2 and 4.3, respectively). Kaplan-Meier graft survival curves were similar to Nyberg data: 83% for class C versus 73% for class D at 5 years. Without any comparison to the Nyberg score, the only feature that was predictive of renal function at 5 years in our population was hypertension in the donor. Further studies are required to identify which of the scoring systems--clinical and/or histological--is more suitable to allocate ECD kidneys and to predict recipient outcomes.