Last week the United Network for Organ Sharing (UNOS) set forth proposal 3.5 to change the allocation of deceased donor kidneys. The new proposal aims to improve transplant access to blood type B donors (longest waiting time), increase transplant access to minorities, improve transplantation rates in highly sensitized candidates, enhance sharing of kidneys between regions, and reduce the discard rate of organs. Specific policy changes to achieve these goals include allocating rare A2 blood type kidneys to blood type B recipients, awarding points on a sliding scale to sensitized patients, and allowing patients to accumulate wait time from the point they started dialysis. What has garnered the most attention however, as is summarized in a recent New York Times article, is improving the number of life-years gained from the current deceased donor pool by matching the top 20% of kidneys to the 20% of transplant candidates expected to live the longest.
Kidney quality will be determined by the KDPI (Kidney Donor Profile Index), eliminating standard criteria (SCD) and expanded criteria (ECD) definitions. Donor organs will be divided into 4 groups: KDPI ≤20%, KDPI >20% but <35%, KDPI ≥35% but ≤85%, and KDPI >85%. Organs with KDPI ≤20%, or the “best” organs, will be allocated to those recipients expected to have the longest estimated post-transplant survival (EPTS). EPTS is based on four factors: age, length of time on dialysis, prior transplant, and diabetes status, all of which are negative factors. Higher EPTS scores are associated with lower expected patient survival. Therefore, this policy creates a disadvantage for older patients, patients with a prior transplant, those who have been on dialysis the longest, and diabetics.
So what is more important—saving more lives or being non-discriminatory? The proposed changes are estimated to result in an additional 8,380 life-years achieved annually from the current pool of deceased donors. It is difficult to argue against allocating the limited pool of kidneys to save as many lives, and for as long as possible. But at the same time, we must ask if there could be a way to still help the older diabetic patients who perhaps need a kidney even more desperately than the younger healthier candidates. Often, elderly diabetic patients do not need a kidney to last longer; rather they need a kidney faster. Evidence of this can be extracted from trials of ECD kidneys. In a 2005 study published in JAMA, it was shown that older diabetic patients enjoy a mortality benefit from accepting an ECD kidney by spending less time on the wait list, while younger healthier patients do not experience the same benefit. A recent study published by AJKD also demonstrated excellent graft survival for elderly transplant patients with ECD kidneys. Therefore, if allocating the “best” kidneys to young healthy patients, perhaps kidneys with a high KDPI should be preferentially allocated to patients with a high EPTS score; or in other words, to elderly and diabetic patients who have been waiting on dialysis the longest. This would allow them to receive exactly what they need—a kidney transplant as fast as possible.
The policy is set for public commentary from September 21to December 14, 2012. It shall be considered by the Board of Directors in June 2013. Approved or not, a heated debate on the allocation of deceased donor organs in the USA is about to ensue.
Dr. Vinay Nair
Mount Sinai School of Medicine
eAJKD Advisory Board member
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