Nudging the Organ Discard Problem
In this issue of Transplantation, several articles evaluate policies introduced by the United States Organ Procurement and Transplantation Network (OPTN) and the UK National Health Service Blood and Transplant (NHSBT) to address the problem above. Their findings illustrate how well-intentioned policies can have unintended consequences when failing to take into account human biases in decision-making.
In Kahneman and Tversky's1 seminal paper in the field of behavioral economics, the authors describe how, when making decisions between prospects and gambles, people tend to make choices that would not be considered rational by traditional economic theory. Instead, people overweight risks of low probability but large potential loss, and prefer a smaller but certain gain to a larger gain that lacks certainty. That is, when seeking gains, we are biased toward risk aversion. Further, perceptions of risk are acutely sensitive to how choices are described. In the context of transplantation, prospect theory predicts that the risk of an adverse outcome will weigh disproportionately heavily in organ acceptance decisions. Physicians and patients will be biased toward waiting longer for a “good” organ instead of accepting an organ described as “increased-risk.” Decisions are made in terms of near-term gains and losses, relative to a patient’s current state of health, rather than in terms of the aggregate lifetime benefit to be gained from a given organ.
The impact of labeling organs as “good” or “bad” has previously been observed with the introduction of the standard criteria/expanded criteria donor (SCD/ECD) classification for kidneys by OPTN in 2002. The ECD classification was introduced to expedite transplantation for patients unable to tolerate a lengthy wait by promoting the retrieval and utilization of “increased-risk” kidneys. However, although retrievals increased, the acceptance rate for kidneys meeting ECD criteria fell and rates of discard remained high.2 Given this result and the limitations of a binary classification system, the OPTN introduced the Kidney Donor Profile Index (KDPI) 2012, and in 2014 implemented a new kidney allocation scheme (KAS) under which kidney offers are made according to 4 tiers of KDPI. The main goals of the KAS were to improve the utility of the existing donor pool by matching KDPI with the estimated posttransplant survival of the recipient, and to expedite transplantation of “increased-risk” kidneys (now defined as KDPI >85%) to recipients who would benefit from them, thereby reducing discards and improving outcomes overall.
Contrary to intended outcomes, however, evaluation of the first 18 months of the KAS shows an increase in the discard rate from 18% to 20%. In the present issue, Heilman et al3 apply prospect theory to eloquently explain this observation. Not only has the introduction of the KDPI not corrected for the labeling effect of the SCD/ECD era (and possibly it has made it worse), the regulatory context in which transplantation programs operate nudges decision making toward loss aversion. Current allocation policies and regulations, they argue, bias physicians and patients away from accepting high KDPI kidneys and make organ discard more likely.