Background: Deceased-donor kidney discard rates remain high. Understanding risk factors for discard is difficult since most analyses lack granularity and sufficient sample of high disease severity cases.
Methods: We analyzed DonorNet® data of consecutive deceased-donor non-mandatory share primary kidney-only offers to adult candidates at our center and beyond between July 1, 2015 and March 31, 2016 for donor risk factors of discard, defined as non-transplantation at our or subsequent transplant centers. Exclusions were HCV/HBV (n=14), blood type AB (n=20), and donor< 1 year (n=25) based on low candidate waitlist size. Results: Of 456 individual kidney offers, from 296 donors, 73% were discarded. Most were national (93%) offers from KDPI 35-85% (n=233) or > 85% (n=208) donors late in the allocation sequence with prior refusals logged for numerous candidates (figure 1). On multivariate logistic regression, factors significantly (p<0.05) associated with discard were:  donor CVA (aOR:3.32), cancer transmission concern (aOR:6.50), renal artery luminal compromise (aOR:3.97), 2-hour pump Resistive Index > 0.4 (aOR:3.27), absence of pump (aOR:2.58), biopsy score ≥3 (aOR 5.09)(table 1).
Conclusion: Many pre-recovery determinants of discard lack discriminatory value when post-recovery factors are assessed. Our findings underscore the importance of improving precision around donor characteristics that constitute an unwanted offer and provide a more codified understanding of how kidneys previously rejected by local and regional centers are selected for transplant.