Retroactive application of the new kidney allocation system to renal transplants performed in the ECD/SCD era

Expanded Criteria Donor Kidneys With Kidney Donor Profile Index ≤ 85%: Are We Doing Enough to Counsel Our Patients?

BACKGROUND

Kidneys at higher risk for allograft failure are defined by the Kidney Donor Profile Index (KDPI) > 85% in the current kidney allocation system (KAS), replacing the historical concept of expanded criteria donor (ECD) kidneys in the previous KAS. Discrepancies exist in the classification of "high-risk kidneys" between the 2 KAS. In the current KAS, only recipients of KDPI > 85% kidneys are counseled about the high risk of allograft failure and are required to sign a consent. In this study, we evaluated the outcomes and allocation of kidneys with discordant classification.

METHODS

Using the Scientific Registry of Transplant Recipients, kidneys transplanted between 01/2002 and 09/2016 were classified according to the old (standard criteria donor [SCD]/ECD) and current (KDPI) KAS. We then grouped them as concordant (KDPI ≤ 85% + SCD or KDPI > 85% + ECD) and discordant (KDPI ≤ 85% + ECD or KDPI > 85% + SCD) kidneys.

RESULTS

Approximately 11% of transplanted kidneys were discordant in classification. Among kidneys with KDPI ≤ 85%, ECD status conferred a 64% (95% CI: 56%-73%) higher risk of allograft failure compared to SCD status. However, SCD/ECD status was not associated with differential outcomes in KDPI > 85% kidneys. These ECD kidneys have KDPIs > 50% and have been transplanted across all estimated post-transplant survival (EPTS) deciles.

CONCLUSION

Adequate counseling about the risk and benefit of accepting ECD kidneys with KDPI ≤ 85% versus waiting on dialysis should be explored with the patients, especially those with lower EPTS.

Utilization of Standard Criteria Donor and Expanded Criteria Donor Kidneys After Kidney Allocation System Implementation

BACKGROUND Implementation of the Kidney Allocation System (KAS) changed how kidneys are allocated and the information on which organ utilization decisions are based. We aimed to evaluate how KAS implementation changed kidney utilization and recipient outcomes. MATERIAL AND METHODS Using the United Network for Organ Sharing database, we identified recipients of kidney transplants from donors with kidney donor profile index (KDPI) of 61-90% in the 5-years pre- and 18-months post-KAS implementation and examined patient and graft survival and donor kidney discard rates based on standard criteria donor (SCD) or expanded criteria donor (ECD) status. RESULTS The proportion of ECD kidneys was unchanged pre- versus post-KAS. Post-KAS, SCD kidneys were less likely to be transplanted into young recipients while ECD kidneys were more likely to be transplanted. SCD kidneys in the post-KAS period conferred a 1.42 (95% CI: 1.18-1.73) times higher adjusted mortality and 2% lower 1-year survival (94.2% vs. 96.2%, P<0.001) but had unchanged graft failure compared to pre-KAS. For ECD kidneys, there was no difference in mortality or graft survival. The discard rate increased after KAS for both SCD and ECD kidneys (P<0.05) but was not different between SCD and ECD kidneys for any KDPI group. CONCLUSIONS After KAS implementation, patient survival for recipients of SCD kidneys was significantly worse.