Major Variation across Local Transplant Centers in Probability of Kidney Transplant for Wait-Listed Patients
Authors: King Kristen L. , Husain S. Ali , Schold Jesse D. , Patzer Rachel E. , Reese Peter P. , Jin Zhezhen , Ratner Lloyd E. , Cohen David J. , Pastan Stephen O. , Mohan Sumit 
Published: October 2020

Significance Statement
Geographic disparities in rates of kidney transplantation have been observed, but the role played by variations in practices at transplant centers versus differences in local organ supply and demand remains unclear. This retrospective national registry study compared the probability of receiving a deceased donor kidney transplant within 3 years of waiting list placement across centers. For the average patient, probability of transplant varied 16-fold between different centers across the United States; up to ten-fold variation persisted between centers working with the same local organ supply. Probability of transplant significantly associated with centers’ willingness to accept offers of organs for wait-listed patients. Large disparities between centers for likelihood of receiving a timely transplant may be related to center-level practice variations rather than geographic differences in underlying organ supply or patient case mix.

Background
Geographic disparities in access to deceased donor kidney transplantation persist in the United States under the Kidney Allocation System (KAS) introduced in 2014, and the effect of transplant center practices on the probability of transplantation for wait-listed patients remains unclear.

Methods
To compare probability of transplantation across centers nationally and within donation service areas (DSAs), we conducted a registry study that included all United States incident adult kidney transplant candidates wait listed in 2011 and 2015 (pre-KAS and post-KAS cohorts comprising 32,745 and 34,728 individuals, respectively). For each center, we calculated the probability of deceased donor kidney transplantation within 3 years of wait listing using competing risk regression, with living donor transplantation, death, and waiting list removal as competing events. We examined associations between center-level and DSA-level characteristics and the adjusted probability of transplant.

Results
Candidates received deceased donor kidney transplants within 3 years of wait listing more frequently post-KAS (22%) than pre-KAS (19%). Nationally, the probability of transplant varied 16-fold between centers, ranging from 4.0% to 64.2% in the post-KAS era. Within DSAs, we observed a median 2.3-fold variation between centers, with up to ten-fold and 57.4 percentage point differences. Probability of transplantation was correlated in the post-KAS cohort with center willingness to accept hard-to-place kidneys (r=0.55, P<0.001) and local organ supply (r=0.44, P<0.001).

Conclusions
Large differences in the adjusted probability of deceased donor kidney transplantation persist under KAS, even between centers working with the same local organ supply. Probability of transplantation is significantly associated with organ offer acceptance patterns at transplant centers, underscoring the need for greater understanding of how centers make decisions about organs offered to wait-listed patients and how they relate to disparities in access to transplantation.