Factors leading to the discard of deceased donor kidneys in the United States

Abstract

The proportion of deceased donor kidneys procured for transplant but subsequently discarded has been growing steadily in the United States, but factors contributing to the rising discard rate remain unclear. To assess the reasons for and probability of organ discard we assembled a cohort of 212,305 deceased donor kidneys recovered for transplant from 2000-2015 in the SRTR registry that included 36,700 kidneys that were discarded. 'Biopsy Findings' (38.2%) was the most commonly reported reason for discard. The median Kidney Donor Risk Index of discarded kidneys was significantly higher than transplanted organs (1.78 vs 1.12), but a large overlap in the quality of discarded and transplanted kidneys was observed. Kidneys of donors who were older, female, Black, obese, diabetic, hypertensive or HCV-positive experienced a significantly increased odds of discard. Kidneys from donors with multiple unfavorable characteristics were more likely to be discarded, whereas unilaterally discarded kidneys had the most desirable donor characteristics and the recipients of their partner kidneys experienced a one-year death-censored graft survival rate over 90%. There was considerable geographic variation in the odds of discard across the United States, which further supports the notion that factors beyond organ quality contributed to kidney discard. Thus, while the discard of a small fraction of organs procured from donors may be inevitable, the discard of potentially transplantable kidneys needs to be avoided. This will require a better understanding of the factors contributing to organ discard in order to remove the disincentives to utilize less-than-ideal organs for transplantation.

Making Procurement Biopsies Important Again for Kidney Transplant Allocation

“…As the authors correctly point out, wedge biopsies contain disproportionately high subcapsular parenchyma and may result in overrepresentation of glomerulosclerosis, interstitial fibrosis, and tubular atrophy compared to needle core biopsies [26]. This sampling issue is likely a contributor to the increased rate of discards attributed to biopsy findings, especially in instances of unilateral discards [5].…”

“…1a). This trend has a dramatic impact on patients on transplant waiting lists, as their survival after 5 years on dialysis is below 40% on average [5]. However, the number of discarded kidneys from deceased donors has increased, mostly as a consequence of the aging of the donor pool (Fig.…”

“…The expanded criteria donor program was established in 2002 in the United States to increase the use of organs from donors with ≥60 years or comorbidities [8]. However, since its implementation, the discard rates have further increased [5]. Major determinants of discarded kidneys were donor comorbidities and biopsy findings on wedge biopsy (percentage of glomerulosclerosis) [5] (Fig.…”

“…However, since its implementation, the discard rates have further increased [5]. Major determinants of discarded kidneys were donor comorbidities and biopsy findings on wedge biopsy (percentage of glomerulosclerosis) [5] (Fig. 2).…”

“…For example, a donor with a KDPI of 70% has a higher expected risk of graft failure than 70% of all recovered kidney donors within the last year. However, implementation of the KDPI score to allocate donor organs is still associated with significant kidney discard rates [5].…”