The rate of glomerulosclerosis as a potential criterion for allocation of marginal kidneys into single or dual kidney transplantation

Background: Globally, the proportion of marginal donor kidneys (MDKs) has steadily increased. Dual kidney transplantation (DKT) has emerged as an effective strategy to reduce the discard rate of MDKs. Pre-transplant renal graft biopsy plays a pivotal role in determining the utilization of MDKs and the allocation into DKT. However, within the widely adopted Remuzzi scoring system, the recommendation for DKT in cases with scores of 4–6 lacks sufficient accuracy.
Methods: Between December 2017 and December 2023, a total of 79 DKT were performed at our center. Among these, 56 cases with bilateral glomerulosclerosis (Gs) rate ranging from 25% to 50% were included in present study (the DKT group). During the same period, 84 recipients who underwent marginal single kidney transplantation with the same Gs rate range of 25% to 50% were identified (the m-SKT group). Additionally, 168 SKT with graft Gs rate <25% were selected using 1:2 matching as a control group (SKT group). Transplant outcomes were compared among the three groups.
Results: Organ source were predominantly donation after circulatory death (DCD) across all groups (DKT: 76.8%; m-SKT: 86.9%; SKT: 80.4%). The Gs rate in the DKT, m-SKT, and SKT groups were (37.55 ± 7.39) %, (31.02 ± 6.54) %, and (9.89 ± 7.56) %, respectively. Corresponding Remuzzi scores were 5.08 ± 0.96, 4.18 ± 0.97, and 2.29 ± 1.49. The incidence of delayed graft function was similar across groups (DKT: 32.1%; m-SKT: 33.3%; SKT: 28.6%; P > 0.05). During a median follow-up of 55 months, graft function in the DKT group was comparable to that in the SKT group, whereas significantly inferior function was observed in the m-SKT group (Figure 1). The 1-, 3-, and 5-year graft survival rates were 100% vs. 94% vs. 100%, 94% vs. 80.9% vs. 95.8%, and 91% vs. 75.8% vs. 92.9% in the DKT, m-SKT, and SKT groups, respectively (Figure 2), indicating comparable outcomes between DKT and SKT, but significantly reduced graft survival in the m-SKT group. Furthermore, in cases with a Remuzzi score of 4, the m-SKT subgroup (n = 33) demonstrated significantly lower eGFR at 24 months post-transplant compared with that in the SKT subgroup (n = 20) (38.92 ± 10.95 vs. 53.76 ± 14.62 mL/min/1.73 m², P < 0.05), suggesting that different Gs rate burdens may lead to distinct graft outcomes despite identical Remuzzi scores.
Conclusions: For marginal donor kidneys with Gs rate ranging from 25% to 50%, DKT significantly improves mid-term graft survival. Post-procurement biopsy-derived Gs rate provides a practical and an appropriate criterion for allocation of marginal kidneys into single or dual kidney transplantation.