Will Switch to the KDRI Allocation System Improve Kidney Transplant Outcomes?: A Single-Center Retroactive Analysis.

Abstract

Objective: The new kidney donor risk index (KDRI) allocation system aims to maximize resource utilization in deceased donor kidney transplantation by improving donor-recipient matching. We estimate the impact of the KDRI allocation system on patient and graft outcomes through retroactive application of the KDRI system. Methods: 528 adult deceased donor kidney transplants were performed between 2004 and 2012, and organs were allocated using clinical judgment and extended criteria/standard criteria donor (ECD/SCD) categorization. Donor KDRI and recipient estimated post-transplant survival (EPTS) were retroactively calculated. Post-transplant graft and recipient survival were compared between those grafts allocated in accordance with the KDRI system and those not. Transplants were considered to be in accordance with the KDRI system if the best donor kidneys (top 20% by KDRI) were allocated to the best recipients (top 20% by EPTS), and if the remaining donor kidneys were allocated by restricting donor-recipient age difference to 15 years or less. Results: Mean donor and recipient ages were 44.1 and 51.2 years respectively. Mean calculated KDRI and raw EPTS score were 0.80 and 1.70 respectively, with poor correlation among transplants (r2=0.005). 22.8% of the best donor kidneys were allocated to the best recipients. Donor-recipient age difference was 15 years or less in a majority (68.1%) of transplants. Allocation of the best donor kidneys to the best recipients was not associated with improved graft or patient survival. Donor-recipient age restriction to 15 years or less was associated with worse graft survival, but similar patient survival (Figure). Improved graft survival by age difference was only noted when the donor was more than 15 years younger than the recipient (p<0.01).Figure: No Caption available.Conclusions: In this single center analysis, retroactive application of the KDRI system did not provide superior transplant survival outcomes as compared to allocation by clinical judgment and ECD/SCD categorization. Larger studies are required to assess whether this system will improve kidney transplant outcomes.