September 21, 2012

Public comment sought on proposed revisions to deceased donor kidney allocation policy

Richmond, Va. – The OPTN/UNOS Kidney Transplantation Committee is seeking public comment regarding substantial proposed amendments to OPTN deceased donor kidney allocation policy. The proposed policy would maintain access to kidney transplantation for all candidates while seeking to improve outcomes for kidney transplant recipients, increase the years recipients may have a functioning transplant and increase utilization of available kidneys.

Matching to increase benefit and utilization

More than 93,000 people are currently listed for kidney transplantation nationwide. About 10 percent of those candidates die each year while waiting. Because there are not enough kidneys donated to meet the need, it is important to improve benefit by matching recipients according to the potential function of the kidney and ensure as many kidneys as possible are transplanted.

The proposed policy includes new factors not used in the current policy. Their use is recommended to enhance survival benefit and use of available kidneys.

  • Kidney Donor Profile Index (KDPI) The proposed policy would replace the existing policy definitions of “standard criteria” and "extended criteria" donors with the Kidney Donor Profile Index (KDPI). KDPI is a clinical formula to classify kidney offers based upon the length of time they are likely to continue to function once transplanted. This index is already in use as a resource for transplant professionals to evaluate kidney offers made under the current policy.

    Estimated Post-transplant Survival (EPTS) The proposed policy would separately employ a clinical formula to estimate the number of years each specific candidate on the waiting list would be likely to benefit from a kidney transplant. This score is called the Estimated Post-transplant Survival formula (EPTS). For more information about KDPI, EPTS and current policy definitions of “standard” and “extended criteria” donors, read the frequently asked questions (FAQ) document.

  • KDPI and EPTS matching Under the proposed policy, KDPI and EPTS would be combined so that the 20 percent of kidney offers with the longest estimated function determined by the KDPI would first be considered for the 20 percent of candidates estimated by the EPTS to have the longest time to benefit from a transplant. This policy revision is expected to create significant benefit in terms of overall "life-years" (time that recipients retain kidney function after the transplant). This improvement in utilization of the limited number of donated deceased kidneys may reduce recipients’ future need for repeat transplants, thus allowing more transplants among candidates awaiting their first opportunity.

    For the remaining 80 percent of transplant candidates, the organ offer process would be much the same as the existing system unless they receive additional priority based on other considerations addressed below.
  • Promoting greater utilization The 15 percent of kidney offers estimated to have the shortest potential length of function based on KDPI score would be offered on a wider geographic basis. Similar to the use of currently defined “extended criteria donor” kidneys, these offers may be considered for candidates who would have a better life expectancy with a timely transplant than they would remaining on dialysis. This feature is expected to increase utilization of donated kidneys currently available for transplant. It may also help minimize differences in local transplant waiting times across different regions of the country.

    The proposed policy would not change the decision-making process between an individual candidate and his or her transplant team regarding the characteristics of kidney offers they would be willing to accept for a transplant. The use of KDPI will provide the candidate and transplant team a clearer understanding of the potential function of the kidney to allow for more informed treatment decisions.

  • Waiting time calculation As in the current kidney allocation system, the proposed policy would continue to award progressively higher priority to candidates based on their waiting time for a transplant. The current national default policy assigns waiting time when the candidate is listed with a program, even if the candidate had begun dialysis or met other criteria for end-stage kidney failure before being listed.

    Candidates who are not listed for a transplant promptly upon end-stage kidney failure may have more advanced disease and experience greater health complications than those listed earlier for a transplant. Studies have shown that some ethnic minority candidates are more likely than Caucasians to experience a delay in listing. Under the proposed policy, once a person is accepted as a transplant candidate, waiting time will be calculated from the date the person first had a GFR score (a standard clinical measure of kidney function) less than or equal to 20 ml/minute, or when the candidate began dialysis or other renal replacement therapy, even if that date preceded the transplant listing.

Access for candidates with biological disadvantages

Some groups of candidates currently face potentially longer waiting times than others because of biological factors. The proposal would establish new provisions to provide such candidates access to transplantation at a rate more consistent with candidates who do not have these biological disadvantages.

Some candidates have relatively uncommon blood types that are incompatible with many donors. The proposal would establish in national policy a provision already used in some local areas to offer kidneys from donors with certain subtypes of blood type A for transplant candidates with blood type B. Some type B candidates are compatible with donors who have these specific subtypes.

Other candidates have developed high immune system sensitivity based on antibodies developed due to previous transplants, prior blood transfusions and/or pregnancy. The level of immune sensitivity is measured in a percentage using a calculated panel reactive antibody (CPRA) score. A candidate with a CPRA of 40 percent, for example, is expected to be incompatible with 40 percent of available kidney offers.

The proposal would establish a sliding scale of additional priority for candidates with a CPRA score beginning at 20 percent. Since extremely highly sensitized candidates (CPRA score of 98 percent or higher) have very few opportunities for a compatible transplant, they would receive higher proportional priority than those with more moderate sensitization levels.

Additional recommendations

The proposed policy would end the practice of "payback" kidney offers owed when a local transplant area accepts a very well-matched kidney offer from a different local donation service area. Research has not shown any definable benefit in recipient outcomes from payback offers.

The proposed policy would also dissolve a number of alternate kidney allocation systems currently operated in different local areas of the country. Many of these local systems were intended to study allocation methods now incorporated into the national policy proposal.

Providing comment/process for further consideration

The full proposal is available on the OPTN Web site. Anyone who has an interest may submit comments or questions on this or other current proposals.

The Kidney Transplantation Committee will review all comments submitted through December 14, 2012, and address any substantive questions or suggestions; the committee may amend its final proposal based on public feedback and additional discussion. The committee will then present its recommendations to the OPTN/UNOS Board of Directors. The earliest the Board may take a final vote on a new policy would be at its June 2013 meeting.

The Organ Procurement and Transplantation Network (OPTN) is operated under contract with the U.S. Department of Health and Human Services, Health Resources and Services Administration, Division of Transplantation by the United Network for Organ Sharing (UNOS). The OPTN brings together medical professionals, transplant recipients and donor families to develop organ transplantation policy.