Background: The proportion of deceased donor kidneys recovered for transplant but discarded increased steadily in the United States over 2 decades, from 5.1% in 1988 to 19.2% by 2009. Over 100 000 patients are waiting for a kidney transplant, yet 3159 kidneys were discarded in 2015.
Methods: We evaluated trends in donor characteristics, discard reasons, and Organ Procurement Organization–specific discard rates. Multivariable regression and propensity analysis were used to estimate the proportion of the discard rate rise in the 2000s attributable to changes in donor factors and decisions to biopsy and pump kidneys.
Results: This study found that at least 80% of the discard rate rise can be explained by the recovery of kidneys from an expanding donor pool and changes in biopsy and pumping practices. However, a residual discard rate increase could not be explained by changes in these factors. From 1987 to 2009, median donor age rose from 26 to 43 years; median Kidney Donor Risk Index increased from 1.1 in 1994 to 1.3 in 2009. Our findings suggest that the increase from 10% to 30% in the proportion of kidneys pumped during the 2000s served as a buffer, keeping the discard rate from rising even higher than it did.
Conclusions: The majority of the kidney discard rate rise can be explained by the broadening donor pool. However, the presence of an unexplained, residual increase suggests behavioral factors (eg, increased risk aversion) and/or allocation inefficiencies may have played a role. Reducing risk aversion, improving allocation, and more often pumping less-than-ideal, yet potentially transplantable kidneys, may help reverse the trend.
Kidney discard rate must always be minimized. Using multivariable regression and propensity analysis, the authors show that, in the USA, 80% of the discard rate is explicable by donor factors and biopsy results or perfusion pump parameters. Interestingly, they suggest that the increasing use of pumped perfusion has been associated with a decreased discard rate in recent years.
1 United Network for Organ Sharing, Richmond, VA.
Received 2 June 2016. Revision received 27 September 2016.
Accepted 29 September 2016.
The authors declare no funding or conflicts of interest.
D.E.S. designed and guided all aspects of the study; drafted and finalized article. V.C.G. performed statistical modeling; generated tables and figures. J.D.R. provided intellectual guidance; reviewed and edited article. D.K.K. provided intellectual guidance; reviewed and edited article. B.J.C. provided guidance on study design, methods, and interpretation; reviewed and edited article.
Correspondence: Darren E. Stewart, MS, UNOS 700N. 4th St Richmond, VA 23219. (firstname.lastname@example.org).