Improving the Supply and Allocation of Transplantable Organs
Scholar: Scott D Halpern, MD, PhD
More than 100,000 Americans currently await an organ transplant, and more than 10,000 die or become too sick to receive a transplant each year. Thus, improving organ donation and allocation are essential public health goals. Greenwall Faculty Scholar Dr. Scott Halpern has blended careful conceptual analyses with innovative epidemiologic studies to clarify the ethics and opportunities in organ donation, and to identify more efficient and equitable allocation systems.
Can (and should) we increase the supply of transplantable organs through better utilization of donors after circulatory determination of death, or “non-heart-beating donors”?
Most transplantations in the U.S. come from donors who have been declared dead on the basis of neurological criteria (also known as brain-dead donors). However, because brain-dead donors will never fill the gap between the supply of demand for organ transplants, additional organ donors are needed.
Donors who are declared dead on the basis of circulatory criteria, also known as non-heart-beating donors or donors after cardiac death (DCD), are a large potential source of organs. In one study, Dr. Halpern and colleagues found that the supply of all deceased organ donors could be increased by about 10% if only optimal organs from DCD were used, and by up to 25% if less restrictive criteria for organ acceptability were employed (source). The authors further found that three-quarters of all of DCD organs could be obtained from only 17% of hospitals; those which have a trauma center and more than 20 ICU beds (source). These findings suggest great potential for efficiencies in the recovery of DCD organs.
A potential challenge to DCD is concerns by ICU physicians and nurses about conflicts of interest and impact on end-of-life care. Dr. Halpern helped address this problem with a national survey of critical care physicians and nurses. He found that nearly three quarters of physicians and nurses believed they should promote DCD, particularly when there was evidence that it was consistent with patients’ wishes. Greater familiarity with DCD was generally associated with increased willingness to help patients become donors (source). Dr. Halpern also co-led a consensus statement on the ethical and policy issues relevant to DCD that was jointly endorsed by multiple professional societies (source), which suggested best practices for several delicate issues including of consent for DCD, how DCD can be consistent with high-quality end-of-life care, and whether and how to use interventions on donors for the purpose of promoting the quality of the donation.
Paying patients or their families for becoming organ donors is illegal. Would concerns about payment manifest if payment was actually offered?
Currently neither patients nor their families can be paid for becoming donors. Several sensible concerns have been offered for these prohibitions. Payment might represent an undue inducement, blinding people to the risks of kidney donation and undermining autonomous choice. Payment might also represent an unjust inducement, preferentially appealing to poorer people. Finally, some are concerned that payments would reduce altruistic donations on which the current system is based.
To test these concerns, Dr. Halpern and colleagues conducted a randomized experiment of more than 400 Americans from diverse backgrounds in which the researchers varied the hypothetical amount people would get paid to donate a kidney, the disclosed risks of donation, and whether people were alerted to the possibility of payment before being asked whether they would donate for free (source). As expected, the investigators found that more people would donate one of their kidneys when payments were offered. However, there was no evidence that peoples’ consideration of risk changed in the face of money, that poorer people were more likely to respond to payment, or that offering payment decreased people’s willingness to donate altruistically. Because of the absence of evidence of the presumed ethical problems, the authors suggest that it is time for a real-world test of payments for living kidney donation.
Dr. Halpern and colleagues have discovered two ways to make better use of the existing supply of transplantable lungs.
Lung transplantation offers the only possible treatment for many forms of life-threatening lung diseases. However, due to the scarcity of lungs, many people who could benefit from transplant are never listed. Dr. Halpern and colleagues have worked to improve the equity and benefits obtainable from the U.S. lung supply.
First, Dr. Halpern and colleagues found considerable variability in the risk-adjusted outcomes of patients transplanted at different centers (source). Half of all lung transplant procedures in the U.S. take place at institutions whose survival is more than 50% worse than the best centers. Survival might therefore be improved by exporting the practices of the best institutions to the lower-performing centers, or by referring more patients to the better-performing centers.
Dr. Halpern and colleagues also showed that transplanting a single lung to patients with chronic obstructive pulmonary disease (COPD) rather than a double-lung transplant could improve the number of lives saved because two patients could often be saved by each donor, rather than one (source). Importantly, the authors determined that even if double-lung transplantation conferred a much larger survival advantage for the individual recipient, a national policy of single-lung transplantation for COPD may still produce more total life-years gained by all patients awaiting transplant.
Timely assessments of biases in organ allocation decisions can meaningfully improve the equity and efficiency of these life-saving procedures.
As with all complex decisions that must be made under time-constrained circumstances, biases might influence physicians’ judgments regarding who to accept as potential organ recipients and which organs to accept for attempted transplantation. For example, in the late 1990s and early 2000s there were widespread bans on HIV-infected patients receiving transplants despite emerging evidence that such procedures might be performed safely and effectively. Dr. Halpern and colleagues were the first to critique this norm, arguing that it was untenable to allow transplantation for persons with post-transplant outcomes known to be inferior, such as persons with hepatitis C, diabetes, and those requiring a second transplant, while prohibiting transplantation for HIV-infected persons because clear evidence of equal post-transplant outcomes had yet to be established (source). Subsequently it was shown that outcomes in properly selected HIV-positive recipients are similar to those in HIV-negative recipients.
The organ supply can be increased considerably by using organs that are slightly less than optimal, such as those from donors who are older or have risk factors for certain infections. Although these organs might not produce the same survival advantage as would “perfect” organs, patients might reasonably accept suboptimal organs rather than risk dying without any transplant. Dr. Halpern and colleagues noted the considerable variability in what prospective transplant patients are told regarding the risks of transplantation and how they are involved in decisions to accept or reject a particular organ being offered, Halpern and colleagues argued for a systematic overhaul of the informed consent processes (source), calling for equitable, standardized practices at all centers for informing prospective recipients of the known and uncertain risks of transplantation, and giving them an opportunity, to accept or decline organs from non-standard donors. Based on these arguments, the U.S. Public Health Service recently revised its recommendations regarding consent for organ transplant recipients (source).