Why So Many Kidneys Are Discarded: An Analysis of 36,700 Discards

Discarded and transplanted deceased-donor kidneys overlap considerably in quality, with many potentially transplantable organs being discarded, suggests a study in Kidney International.

Using the Scientific Registry of Transplant Recipients, the researchers identified 212,305 deceased-donor kidneys recovered for transplantation between 2000 and 2015. Of these, 36,700 kidneys were discarded: a rate of 36.7%. Reasons for organ discard were analyzed, along with associated donor- and organ-related factors. The quality of transplanted and discarded organs was compared using the Kidney Donor Risk Index and the Kidney Donor Profile Index.

Three-fourths of discarded kidneys were bilateral discards. The most common reason for discard was “biopsy findings” (38.2%); others included inability to locate a recipient (14.6%), “poor organ function,” (9.6%), and “other” (16.3%). Discarded kidneys had a higher median Kidney Donor Risk Index, 1.78 versus 1.12, but there was large overlap in scores between discarded and transplanted kidneys.

Discard was more likely for kidneys from donors who were black, obese, diabetic, or positive for hepatitis, and from donors with multiple unfavorable characteristics. Unilaterally discarded kidneys—which accounted for 21.5% of all discards—were from donors with the most desirable characteristics. The transplanted partner kidneys from these donors had good outcomes, with 1-year death-censored survival of over 90%.

The likelihood of discard showed considerable geographic variation, with increased odds of discard for organs recovered in the Southeast, Southwest, and part of the Midwest region.

The number of deceased-donor kidneys that are recovered but subsequently discarded has been rising steadily in the United States. The factors associated with this trend are unclear.

The new analysis confirms the significant overlap between kidneys that are transplanted versus discarded. Although some discards are inevitable, the researchers write, “this overlap suggests that there are opportunities for improving allocation to facilitate increased utilization.” They discuss the issues raised by organs with “no recipient” located and the rising rate of unilateral kidney discards [Mohan S, et al. Factors leading to the discard of deceased donor kidneys in the United States. Kidney Int 2018; DOI: https://doi.org/10.1016/j.kint.2018.02.016].