Increasing Access to Kidney Transplantation for Black and Asian Patients Through Modification of the Current A2 to B Allocation Policy.

Abstract

The rate of A2 to B incompatible (ABO-i) kidney transplant continues to be low despite measures in the new Kidney Allocation System (KAS) to facilitate such transplants. This paper shows how the number of ABO-i transplants could increase if KAS policies were utilized to their fullest extent through a boost in ABO-i priority points. Predicting transplant outcomes using the Kidney Pancreas Simulated Allocation Model (KPSAM), preloaded with national data of 2010. We used this simulation to compare KAS to a new intervention in which priority equal to cPRA=100 has been given to blood type B candidate who are willing to accept an A blood type organ. The number of African American recipients increased by 375 (from 35% of recipient population to 38.7%), the number of blood type B African Americans increased by 65 (from 8% of recipient population to 9%), and the number of blood type B African Americans receiving blood type A kidneys increased by 49 (from 2% of recipient population to 2.5%). The same change occurred for Asians, particularly blood type B Asians (from 0.54% of the recipient population to 0.7%). Average wait time notably decreased by 27 days for blood type B African Americans. In the proposed scenario, 263 blood type B African Americans received blood type A organ (2.5% of recipient population) while only 181 (1.1%) of such transplants were performed in 2021. These results signify a considerable opportunity loss of ABO-i transplants for African American patients. If this policy was universally adopted, we would expect to see an overall increase of A2 to B transplantation, but in reality, not all centers perform ABOi transplantation. Thus, adopting this policy would incentivize other centers to perform more subtyping of A-type kidneys, and it would increase access to organs for blood type B Asian and African Americans in centers where ABOi transplantation already takes place.