Epidemiology of Kidney Discard from Expanded Criteria Donors Undergoing Donation after Circulatory Death

Abstract

Background and objectives: The broader use of combined expanded criteria donor and donation after circulatory death (ECD/DCD) kidneys may help expand the deceased donor pool. The purpose of our study was to evaluate discard rates of kidneys from ECD/DCD donors and factors associated with discard.

Design, setting, participants, & measurements: ECD/DCD donors and kidneys were evaluated from January 1, 2000 to March 31, 2011 using data from the Scientific Registry of Transplant Recipients. The kidney donor risk index was calculated for all ECD/DCD kidneys. Multivariable logistic regression models were used to determine risk factors for discarding both donor kidneys. The Kaplan-Meier product limit method and the log-rank statistic were used to assess the cumulative probability of graft failure for transplants from ECD/DCD donors where the mate kidney was discarded versus both kidneys were used.

Results: There were 896 ECD/DCD donors comprising 1792 kidneys. Both kidneys were discarded in 44.5% of donors, whereas 51.0% of all available kidneys were discarded. The kidney donor risk index scores were higher among donors of discarded versus transplanted kidneys (median, 1.82; interquartile range, 1.60, 2.07 versus median, 1.67; interquartile range, 1.49, 1.87, respectively; P<0.001); however, the distributions showed considerable overlap. The adjusted odds ratios for discard were higher among donors who were older, diabetic, AB blood type, and hepatitis C positive. The cumulative probabilities of total graft failure at 1, 3, and 5 years were 17.3%, 36.5%, and 55.4% versus 13.8%, 24.7%, and 40.5% among kidneys from donors where only one versus both kidneys were transplanted, respectively (log rank P=0.04).

Conclusions: Our study shows a significantly higher discard rate for ECD/DCD kidneys versus prior reports. Some discarded ECD/DCD kidneys may be acceptable for transplantation. Additional studies are needed to evaluate the factors that influence decision making around the use of ECD/DCD kidneys.

Keywords: cadaver organ transplantation; donation after circulatory death; epidemiology and outcomes; expanded criteria donor; kidney; kidney transplantation; registries; risk factors; tissue donors; transplant recipients.

Figure 1.

Study flow diagram. DCD, donation after circulatory death; ECD, expanded criteria donor; KDRI, kidney donor risk index.

Figure 2.

Box plots and kernal density plots demonstrating significant overlap in kidney donor risk index scores in donors of transplanted and discarded kidneys. (A) Box plots of kidney donor risk index scores among donors of discarded and transplanted expanded criteria donor and donation after circulatory death (ECD/DCD) kidneys. (B) Kernel density plot of kidney donor risk index scores from donors of discarded ECD/DCD kidneys (solid line) and donors of transplanted ECD/DCD kidneys (dashed line); the vertical dashed line represents the median kidney donor risk index of donors of transplanted kidneys.

Figure 3.

The cumulative probabilities of total graft failure are higher among kidneys from donors where only one kidney was used compared to donors where both kidneys were used for transplantation. Kaplan–Meier curves for total graft failure among recipients of expanded criteria donor and donation after circulatory death kidneys from deceased donors where neither versus one kidney was discarded.