Purpose: We hypothesize that improving access to highly sensitized candidates in new KAS would compromise the prime objective of matching the best kidney allografts and candidates.

Methods: Using the UNOS data, we evaluated the impact of allocation on kidneys with low Kidney Donor Performance Index (KDPI) (≤20%) in the new KAS (12/4/2014 to 6/30/2016) and compared it to the old system (12/4/2012 to 12/3/2014).

Results: After exclusion of multi-organ (n=5994) and living donor transplants (n=20,055), there were 3848 of 18,376 recipients with low KDPI in KAS (KAS cohort), and 4405 of 21,413 recipients in old system (control cohort). In the KAS cohort, the mean Expected Post-Transplant Survival (EPTS) was lower (0.24 vs 0.46, p<0.0001), and mean calculated Panel Reactive Antibodies (cPRA) higher (28.9% vs 26.3%, p=0.003), suggesting, in the big picture, that prime objectives may have been met. However, the national share was higher (17% vs 12%, p<0.0001), cold ischemia time (CIT) longer (16.3 hrs vs 15.5, p<0.0001), recipient age higher (44.6 yrs vs 36.8 yrs, p<0.0001), delayed graft function (DGF) higher (16.1% vs 13.9%, p=0.0072), and acute rejection higher (9.4% vs 7.9%, p=0.96), all suggesting a potential compromise on outcomes. Graft and patient survival were not significantly different.

523 (13.6%) low KDPI kidneys were allocated to 100% cPRA patients in KAS cohort vs 51 (1.2%) in control cohort. An internal comparison was performed within the KAS cohort between low KDPI kidneys to 100% cPRA candidates vs low KDPI kidneys to others. In the high PRA group, recipient age was higher (47.2 yrs vs 35.1 yrs, p<0.0001), mean EPTS higher (0.47 vs 0.20, p<0.0001), CIT longer (20.9 hrs vs 15.6 hrs, p<0.0001), and DGF higher (22.4% vs 15.1%, p <0.0001). There was no significant difference in acute rejection (9.8% vs 9.4%, p=0.96), graft survival (p=0.75), or patient survival (p=0.09).

Conclusion: In an unintended consequence, a disproportionately large number of high quality kidneys are now being allocated to high PRA recipients. The follow-up period is likely too short to capture differences in patient and graft survival. However, several factors indicate potential compromise in long term outcomes, going against the prime objective to match KDPI and EPTS. A national policy may be needed to restrict the disproportionate allocation of low KDPI kidneys to high PRA patients.

CITATION INFORMATION: Murthy B, Galvan N, Moffett J, O'Mahony C, Goss J, Rana A. Unintended Consequence of the New Kidney Allocation System – Disproportionate Allocation of High Quality Kidneys to Highly Sensitized Recipients. Am J Transplant. 2017;17 (suppl 3).

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