*Purpose: International discussions in 2017 about kidney “discard rates” between transplant (TX) professionals in the US and UK led to the realization that the two countries’ approaches for quantifying this rate may not be directly comparable. While both define this rate as the % of kidneys recovered for TX that aren’t TXed, in the UK kidneys are almost never recovered prior to TX program acceptance, whereas pre-acceptance recovery is common in the US. We compared trends in several kidney utilization rate calculations and other recovery and usage patterns across countries to identify cross-country learning opportunities.

*Methods: We analyzed deceased donor kidneys (recovered; TXed) from 2006-2017 in the OPTN and UK Transplant registries. Donor age and Kidney Donor Risk Index (KDRI) distributions were compared. The utilization rate (UR) was defined as the number of transplanted kidneys divided by various denominators, to assess trends and attempt to provide cross-country comparisons. Rates were stratified by KDRI and other factors.

*Results: Regardless of definitions, kidney URs have been steady in both countries over the past 5 years (Fig 1). Among kidneys recovered for transplant (solid curves), 90% are utilized in the UK vs. 81% in the US, despite substantially higher KDRI and age distributions in the UK among both recovered and TXed kidneys (Fig 2). In the US, 95% of kidneys with a documented final acceptance are utilized.

In 2017, 41% of utilized kidneys in the UK were from DCD donors compared with 19% in the US. Only 0.8% of kidneys TXed in the UK were en bloc compared with 2.6% in the US.

*Conclusions: International URs must be compared cautiously due to differing recovery, allocation, and acceptance practices that influence the metrics. Useful URs should help identify opportunities to increase organ utilization. Tracking multiple URs can help spotlight different improvement opportunities. While the US may benefit from experience in the UK in the use of older, marginal, and DCD donors, the US may offer insights into expanded use of very young kidneys en bloc in the UK. Future work is needed to enable cross-country comparisons of UR’s relative to potential kidney donors, not just those currently realized by transplant systems.

« Back to 2019 American Transplant Congress