Calibration of Priority Points for Sensitization Status of Kidney Transplant Candidates in the United States

Key PointsThere are multiple factors associated with high sensitization levels among kidney transplant candidates, which differ by candidate sex.Since the initiation of the kidney allocation system, candidates with higher sensitization have higher rates of deceased donor transplantation.Priority points assigned to candidates associated with sensitization have led to inequities in access to deceased donor transplantation.BackgroundA primary change to the national organ allocation system in 2014 for deceased donor kidney offers was to weight candidate priority on the basis of sensitization (i.e., calculated panel reactive antibody percentage [cPRA%]) using a sliding scale. Increased priority for sensitized patients could improve equity in access to transplantation for disadvantaged candidates. We sought to evaluate the effect of these weights using a contemporary cohort of adult US kidney transplant candidates.MethodsWe used the national Scientific Registry of Transplant Recipients to evaluate factors associated with sensitization using multivariable logistic models and rates of deceased donor transplantation using cumulative incidence models accounting for competing risks and multivariable Cox models.ResultsWe examined 270,912 adult candidates placed on the waiting list between January 2016 and September 2023. Six-year cumulative incidence of deceased donor transplantation for candidates with cPRA%=80-85 and 90-95 was 48% and 53%, respectively, as compared with 37% for candidates with cPRA%=0-20. In multivariable models, candidates with high cPRA% had the highest adjusted hazards for deceased donor transplantation. There was significant effect modification such that the association of high cPRA% with adjusted rates of deceased donor transplantation varied by region of the country, sex, race and ethnicity, prior dialysis time, and blood type.ConclusionsThe results indicate that the weighting algorithm for highly sensitized candidates may overinflate the need for prioritization and lead to higher rates of transplantation. Findings suggest recalibration of priority weights for allocation is needed to facilitate overall equity in access to transplantation for prospective kidney transplant candidates. However, priority points should also account for subgroups of candidates who are disadvantaged for access to donor offers.