Accumulated Refusal Count: A Signal of Kidney Nonuse Risk (Brief Communication)

A substantial proportion of recovered deceased-donor (DD) kidneys go unused. Accumulated refusals by transplant centers during the offer process may signal nonuse risk, and quantifying this phenomenon could inform frameworks for rescue strategies or out-of-sequence (OOS) placement. Using OPTN data on adult DD kidneys offered for transplant in 2024, we empirically estimated the probability of nonuse as a function of accumulated refusal count (ARC). Kidneys transplanted OOS were excluded from analysis. Among recovered adult DD kidneys offered in-sequence, risk of nonuse exceeded 50% after ARC=6 for blood type O kidneys, ARC=4 for type A and type B, and after ARC=1 for type AB. Risk exceeded 80% after ARC=128 (type O), ARC=55 (type A), ARC=50 (type B), and ARC=14 (type AB), and exceeded 90% after 980, 414, 278, and 41 refusals, respectively. The C-statistic of the ARC by blood type ranged from 0.896 to 0.933. ARC thresholds offer a pragmatic trigger for rescue allocation, incorporating center perception of kidney quality not easily captured in standard metrics. A policy allowing OPOs to offer kidneys OOS or deploy alternative rescue strategies once a certain ARC threshold is reached may improve utilization of hard-to-place donor kidneys while keeping easier-to-place kidneys in-sequence.