Beyond CPRA: Identifying Sensitized Kidney Candidates with Markedly Low Access to Deceased Donor Transplantation by Granular CPRA and Blood Type

Abstract

Prioritization in the US Kidney Allocation System (KAS) has led to an improvement in the rates of transplantation in highly sensitized (HS) patients. However, there is a subset of HS patients who are at a disadvantage, despite prioritization under KAS. The purpose of this study was to describe the transplant rate (TR) by calculated panel reactive antibody (CPRA) of HS candidates before and five years post-KAS to characterize their access to deceased donor transplants and quantify the number of HS candidates who are at a marked disadvantage in accessing kidneys. Using de-identified OPTN data, the number of solitary deceased donor kidney transplants performed (by month) from June 2013 through December 2019 was analyzed for four CPRA groups (95–97%, 98%, 99%, and 100%), with the CPRA 100% group further stratified into two subgroups (99.5–99.9% and >99.9%). The impact of the recipient blood group was assessed as an additional factor in TR. Immediately after KAS, TR rose 7-fold from 0.26% to 1.7% for the CPRA 99–100% group as a whole, and 12-fold and 8-fold for the CPRA 99.5–99.9% and CPRA 99.9%+ groups, respectively. However, the post-KAS mean TR of 0.63% for CPRA 99.9%+ candidates remained markedly lower than the mean TR of the other sensitized groups: 1.5% for CPRA 95–97%, 1.4% for CPRA 98%, 2.0% for CPRA 99%, and 3.5% for CPRA 99.5–99.9%; a statistically significant 6-fold advantage of the CPRA 99.5–99.9% group over CPRA 99.9%+ candidates was observed, despite both groups receiving national priority under KAS. Patients with a CPRA of 99.9%+ and blood group B were 2.16, 1.98, and 1.75 times less likely to receive a transplant compared to the same CPRA group with blood groups A, AB, and O, respectively, despite changes to KAS allocating blood type A2 and A2B to recipients with blood group B. Although the TR increased sharply for the CPRA 99.9%+ group with KAS, it remained markedly lower than the average despite national priority.