*Purpose: Waitlisting kidney transplant patients before dialysis results in better long-term outcomes. Substantial racial disparities exist for preemptive waitlisting and identification of areas where race is driving geospatial patterns could improve mitigation efforts. Our work is the first to describe preemptive waitlist disparity clusters, which may encourage further study within identified hot spots.

*Methods: 2010-2020 data from 421,750 U.S. kidney transplant candidates in 19,332 zip code tabulation areas (ZCTAs) was obtained from the Scientific Registry of Transplant Recipients. Patients were classified as preemptive or non-preemptive via listing and dialysis dates, followed by race stratification and ZCTA aggregation of patients. A Poisson spatial scan was completed for all races and for white, black, and Hispanic race categories to identify hot spots of non-preemptively listed patients. Maximum cluster sizes based on Gini index values were set at 4%, 10%, 15%, and 20% of the transplant populations for all-race, white, black, and Hispanic patients, respectively. Resulting relative risks (RRs) signified clusters where counts of non-preemptive listings were higher than expected.

*Results: Scan results for black patients revealed two statistically significant hot spots in Florida and the lower southeast. Results for white patients identified five hot spots, including Ohio, southern California, and the southeast. Hispanic results revealed three hot spots in Texas and southern California. Figure 1 shows that specific race categories may be driving all-race hot spots in Figure 2, where Hispanic and white non-preempts may be driving southern California and western Texas hot spots, and black and white non-preempts may be driving Florida and southeastern hot spots. Notably, the Ohio hot spot existed only for white patients.

*Conclusions: Our results constitute the first description of geographic hot spots in kidney transplant non-preemptive waitlisting. Race stratified results showed that black, white, and Hispanic patients have distinct clustering patterns, indicating that further study into patient-level/structural factors causing racial hot spots are warranted and that analyses should be extended to patients never listed.

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