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Continuous Distribution of Kidneys and Pancreata Update

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This paper builds upon the Kidney Transplantation and Pancreas Transplantation Committees’ 2021 concept paper and 2022 request for feedback on the continuous distribution projects. This update provides an overview of the most recent discussions and decisions regarding attributes, rating scales, public input, and the initial modeling request. Finally, this paper provides the next steps for the continuous distribution of kidneys and pancreata project.

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Project Progress

  • The Kidney and Pancreas Transplantation Committees formed a joint workgroup to conduct their continuous distribution projects simultaneously
  • The Kidney-Pancreas Continuous Distribution Workgroup worked to identify goals, key attributes related to kidney and pancreas transplantation, and assign preliminary values to the identified attributes for the modeling request
  • Attributes related to a patient’s overall score include: medical urgency, expected post-transplant outcome, candidate biology, patient access and efficiency of organ placement
  • A higher score puts a patient closer to the top of a match run and more likely to receive an organ transplant

Project Goals

  • Provides a more equitable approach to matching kidneys and pancreas candidates and donors
  • Removes hard boundaries between classifications that prevent kidney and pancreas candidates from being prioritized further on the match run
  • Considers multiple patient attributes simultaneously through a composite allocation score instead of within categories
  • Establish a system that is flexible enough to work for each organ type
  • Having a uniform system will make future policy changes faster

Anticipated impact

  • What it's expected to do
    • Prioritize candidates in a more flexible manner
    • Allow the transplant community to see how much weight is placed on each attribute
    • Improve equity in access to organ transplantation
  • What it won't do
    • This paper is not a proposed policy change, but is an update on the projects. Public Comment feedback will help the Kidney and Pancreas Transplantation Committees develop a future policy proposal.

Terms to know

  • Attribute: Attributes are criteria we use to classify then sort and prioritize candidates. For example, in kidney allocation, criteria include medical urgency, blood type compatibility, HLA matching, and others.
  • Composite Allocation Score: A composite allocation score combines points from multiple attributes together. This concept paper proposes the use of composite allocation scores in a points-based framework.
  • Match run: The list of potential recipients printed by the OPO or Organ Center for each organ recovered for the purposes transplantation from each donor.
  • Modeling: Calculations the Scientific Registry of Transplant Recipients (SRTR) uses to create model predictions on the different attributes and their effect on organ allocation.
  • Rating Scale: A rating scale describes how much preference is given to candidates within each attribute.
  • Weights: Weights reflect the relative importance or priority of each attribute toward our overall goal of organ allocation. Combined with the ratings scale and each candidate’s information, this results in an overall composite score for prioritizing candidates.

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eye iconComments

OPTN Transplant Coordinators Committee | 09/29/2022

The OPTN Transplant Coordinators Committee thanks the Kidney and Pancreas Transplantation Committees for their work and for the opportunity to comment on this concept paper. A member asked how longevity matching would work for pediatric patients, since they are not assigned an EPTS. It was clarified that there is a separate pediatric attribute, which will allow pediatric patients to receive appropriate priority. It was also clarified that the OPTN Pediatric Transplantation Committee submitted a data request recently to see if EPTS was a strong predictor for pediatric patients, and found that it was not. The Pediatric Committee recommended to the Kidney and Pancreas Transplantation Committees that pediatric patients be assigned an EPTS score of 1. One member noted that current kidney allocation gives living donors significant priority, to boost them to the top of the match run. The member expressed concern that living donors may not see this same priority in continuous distribution. Another member agreed, and stressed this importance of prior living donor priority. It was clarified that prior living donors, like pediatrics, will be given priority via the prior living donor attribute, and that the Kidney and Pancreas Committees will need to determine how much weight is appropriate to give to prior living donor priority in order to ensure prior living donors are prioritized similar to their current level of priority. A member noted that during the development of KAS250, there was a lot of work done to match KDPI and EPTS to increase longevity, promote utilization, and help suppress some of the re-transplantation rates. The member emphasized the importance of longevity matching. One member pointed out that, with the implementation of Lung Continuous Distribution, programs will be able to see their candidate’s base CAS score, built from the candidate’s score on the candidate-specific attributes. The member recommended that something similar be included in the implementation of Kidney and Pancreas Continuous Distribution, as this could help programs manage their lists, if they are able to gain a sense of each patient’s general score and where they may show up on a match run. The member added that it would be helpful if that field could be imported into hospital and program data bases, so that programs could manage that on their own end.

American Nephrology Nurses Association (ANNA) | 09/29/2022

In general, ANNA supports the concept of this paper. We would request more information and details about distribution and fairness.

OPTN Transplant Administrators Committee | 09/29/2022

The Transplant Administrators Committee thanks the Pancreas Transplantation Committee and the Kidney Transplantation Committee for their efforts in developing this concept paper. One member suggested the committees consider giving points for recipients that require a pancreas retransplant. There were no further comments from the committee.

Organ Procurement Organization Committee | 09/29/2022

The OPTN Organ Procurement Organizations Committee thanks the Kidney and Pancreas Transplantation Committees for their work and for the opportunity to comment on this concept. A member expressed support for increased emphasis on placement efficiency and distance, but noted that distance is a less effective measure of placement efficiency. The member explained that several other metrics should be considered when considering placement efficiency, such as patient or center density. The member also noted that patient readiness and center behavior impact placement efficiency, adding that there is a need to increase accountability for transplant programs when it comes to pre-recovery offer evaluation responsibilities. The member commented that the placement efficiency rating scale is appropriate, particularly as it could help limit the use of commercial air transportation for kidneys. The member expressed concerns about OPO member participation in the AHP values exercise, particularly noting that the OPO voice could be underrepresented in that group. A member pointed out that a fundamental flaw of the values-based exercise assumes that these are all high quality kidneys. The member explained that the majority of kidneys come from medically complex donors, and that only a small number of centers or patients are interested in accepting some of these harder to place organs. The member emphasized the importance of giving increased weight to placement efficiency for kidneys with a KDPI of 60 percent or higher. The member added that donation is growing amongst those donors that are more medically complex, and that these considerations are necessary as the donor pool expands. The member noted that KDPI is also an imperfect calculation and tool.

American Society for Histocompatibility and Immunogenetics (ASHI) | 09/28/2022

The American Society for Histocompatibility and Immunogenetics (ASHI) and its National Clinical Affairs Committee (NCAC) appreciate the opportunity to provide feedback regarding the continuous distribution framework for kidneys and pancreata. ASHI supports moving from classification-based to point-based framework for allocation as it aligns with the National Organ Transplant Act (NOTA) and the OPTN Final Rule. ASHI agrees with the proposed component for the composite allocation score however as highlighted in the proposal, further work is needed to determine the weight of those components. We support increasing the number of points for individuals with very high cPRA. We do not believe the second and third modeling scenario provides enough point for individuals with very high cPRA. We recommend that large scale modeling should be performed to ensure cPRA is sufficiently weighted as not to disadvantage highly sensitized patients from minority groups as well as multiparous female. We do not believe current modeling (second modeling scenario) attributes sufficient points to the cPRA. Further, we do not support a model where DR matching is attributed more percentage points than cPRA (such as the Third Modeling Scenario). DR matching should provide minimal points compared to cPRA.

Jonathan Fridell | 09/28/2022

I remain very concerned regarding the process for developing continuous distribution specifically for the pancreas transplant element. I participated in the exercise. It was quite alarming that so much weight was placed on prior living donor and pediatric recipients for pancreas allocation. Pancreas transplantation is indicated for patients with diabetes that either need a kidney transplant (either simultaneously (simultaneous pancreas and kidney transplant - SPK) or in sequence if there is a living donor (Pancreas after kidney - PAK) - usually for diabetic nephropathy - or in isolation for patients with potentially life threatening complications of diabetes such as hypoglycemia unawareness (Pancreas transplant alone - PTA). It is extremely unusual for patients in the pediatric age category to meet these criteria - it takes many years to develop diabetic nephropathy or hypoglycemia unawareness. Rarely, a pediatric candidate may require a kidney transplant for another indication and coincidentally have diabetes and may qualify for an SPK or PAK. According to the International Pancreas transplant registry, out of 33,541 pancreas transplants reported, there have only EVER been 39 pediatric pancreas transplants with only 12 of those performed within the last 22 years - and the majority of those were multi organ transplants that would be outside this allocation, for example liver/pancreas transplant for children with cystic fibrosis. Similarly, pancreas transplant recipients all have longstanding diabetes and would not have been considered suitable for living kidney donation. These two queries should never have been included. The responses are extremely heavily weighted towards them, which is not surprising because generally speaking as a transplant community we support transplanting children and prior living donors, but is irrelevant in the case of pancreas transplantation as they are "never events" and did not allow the model to truly characterize the community's opinion regarding the impact of distance and waiting time, which were critical but made up such a small part of the response. I am also concerned about the handling of islet vs whole organ transplant as we are moving toward broader distribution. Please note that whole organ pancreas transplant is recognized as standard of care for suitable candidates whereas (at least currently) islet transplantation is not an approved therapy in the USA. The original DSA based allocation allowed local whole organ pancreas allocation first and then sharing to islet recipients if the BMI>30 or age >50. Somehow, the age was reduced and the local whole organ pancreas allocation first aspect was eliminated. As we move towards continuous distribution, this should certainly be revisited. I would suggest whole organ pancreas offers for all donors for the inner circle and islet using the original criteria of >30 or >50 yo beyond

Region 6 | 09/28/2022

During the discussion some attendees were unclear about the inclusion of “prior living donor” as an attribute for pancreas continuous distribution noting the large number of points given for this attribute. One attendee commented that proximity may be a barrier to optimizing utilization and suggested adding cold ischemia time, particularly in pancreas allocation. Another attendee commented that longer waiting time and distance are the most important pieces of the modeling since both are related to worse outcomes. There was one recommendation to use a gradient for KDPI and not a hard cutoff at 85%. One attendee supported the stepper CPRA scale for kidney allocation in hopes of prioritizing the most highly sensitized candidates. Another attendee noted that future versions of continuous distribution should include cold ischemic time and kidneys on pumps. One attendee noted that there needed to be consideration for SDOH differences. Another attendee commented that due to SRTR and MPSC monitoring, there is less room for taking risks and innovation aimed at getting more people transplanted. One attendee commented that the discard rate has increased significantly with the last allocation change and they were concerned that this change would increase that further.

OPTN Living Donor Committee | 09/28/2022

The Living Donor Committee thanks the OPTN Kidney and Pancreas Transplantation Committees for their continued efforts in developing this project and the opportunity to comment. The Committee strongly supports providing “prior living donors” priority to all living donors, which was also supported in the AHP data provided in the update, as well as other community feedback. The Committee strongly supports maintaining high priority for prior living donors and believes this attribute should be given the appropriate weight to maintain their current level of priority in the new continuous distribution system. In addition to the rationale made in the update paper (reciprocity and as a safety net in recognition of their significant gift), the Committee emphasizes that prioritizing prior living donors is both medically and ethically justified. Living donors make a selfless decision to put their health at risk to improve the life of another human being. Though living donation is relatively safe, there is still intrinsic risk associated with organ donation as outlined in OPTN living donor policy, and a lack of systematic collection of data about long-term outcomes, a project the Committee is currently addressing. Additionally, as the practice of living donation grows, the Committee recognizes the potential for still unknown risks to be associated with donation. Living donors contribute to the transplant system by donating to one waitlisted patient and in doing so, enable transplantation of another waitlisted patient when a deceased organ next becomes available. The Committee supports the societal value of reciprocity to make a donor whole and sending a message to the public that the system values and will stand behind living donors. Additionally, prior living donor priority offers support and assurance to potential living donors and the living donors' families that the system will take care of them should they ever need a transplant.

American Society for Pediatric Nephrology | 09/28/2022

The American Society for Pediatric Nephrology (ASPN) thanks the OPTN for the opportunity to review their request for feedback on Continuous Distribution of Kidneys and Pancreata. Founded in 1969, ASPN is a professional society composed of pediatric nephrologists whose goal is to promote optimal care for children with kidney disease and to disseminate advances in the clinical practice and basic science of pediatric nephrology. ASPN currently has over 700 members, making it the primary representative of the Pediatric Nephrology community in North America. The Society is pleased to note that pediatric (<18 years old) donor kidneys with a KDPI 35-85% will now be included in the priority for pediatric recipients. Current pediatric recipient priority is only for KDPI <35%. The KDPI calculation was designed to predict kidney graft performance in adult recipients and inadvertently led to KDPI scores >35% for young pediatric donors (mostly those <10 years old), making these pediatric donors unavailable for pediatric kidney recipients, for whom the smaller size and renal mass might be appropriate and result in good outcomes. The proposed weighting for continuous kidney distribution is an important correction of this inaccuracy in the KDPI calculation for young pediatric donors and a step towards maximizing utilization of pediatric donor organs for pediatric recipients. The Society is cautiously awaiting results of proposed modeling exercises with the requirement that a continuous distribution allocation system must preserve adequate pediatric access to transplantation. Two specific issues that require monitoring include the (1) use of Estimated Post Transplant Survival (EPTS) scoring and, (2) prioritization of kidney-pancreas candidates. EPTS has not previously been calculated for pediatric candidates, but failing to calculate an EPTS in a continuous distribution framework may mean that pediatric candidates would be disadvantaged when adding up a total points score. There is also a risk that an EPTS score could inappropriately privilege some pediatric candidates over other pediatric candidates. The ASPN would like to ensure that use of the EPTS score be considered for pediatric candidates, but that it be data-driven and not disadvantage any subgroup of pediatric candidates. Regarding simultaneous kidney-pancreas (SKP) transplants. Presently the allocation system favors not only SKP transplant candidates, but all multiorgan candidates over children as well as over sensitized candidates (both pediatric and adult). While few children receive pancreas transplants, SKP prioritization has significant potential impact on pediatric access to kidney transplantation, as the vast majority of SKP candidates receive kidneys with a KDPI <35%. Late turn-downs of SKP transplants can result in <35% KDPI kidneys that have accumulated too much cold ischemia time to be comfortably used in pediatric candidates due to the increased risk of delayed graft function. The ASPN notes that the proposed geographic point allocation for pancreas has a steep drop-off between 50NM and 250NM, suggesting that our pancreas transplant colleagues feel there are significant downsides to pancreata that need to be flown to the recipient’s center, but the suggested policy under review still preserves prioritization for all SKP candidates within 250NM of the donor center. We question whether this acuity circle distance should be decreased, perhaps to 150NM, to help decrease the rate of late turn-downs. Other options may include (1) the introduction of medical criteria for pancreas allocation; (2) prioritization of kidney-alone candidates with composite allocation scores above a particular threshold (that would include most medically urgent, highly sensitized, 0ABDR mismatch, and pediatric candidates) for one kidney from each donor, and/or (3) eliminating the option for OPOs to offer the kidney with the pancreas outside of 250NM until the kidney has been offered to at least a portion of the kidney-alone waitlist. Finally, the ASPN would like to see an allocation policy that is focused not just on waitlist mortality but also on long-term post-transplant outcomes. Kidney transplant candidates vastly outnumber donor kidneys; therefore, maximizing the benefit of each donor gift and decreasing the need for re-transplants should be given at least equal weight with pretransplant mortality. The ASPN would encourage the OPTN to consider graft survival well beyond 1 year in addition to raw transplant numbers, rates, and waitlist mortality. Lastly, modeling of any change in allocation to assess for impact on children and their access to suitable kidneys should be a requirement prior adoption of any new allocation algorithm. Additionally, post-implementation monitoring to access for any unintended or unanticipated consequences to pediatric kidney candidates is essential.

Region 10 | 09/28/2022

Members of the region offered some suggestions for the committees to consider. There was noted support of policies that promote allocation efficiency, but there are many moving parts, and although the process has started, it appears more input is necessary along with a more concrete manner in which these systems will be implemented. Others noted apprehension with changing allocation policies so soon after the removal of DSA and region from allocation, and would implore the committees to carefully weigh the potential impact of the current allocation prior to moving forward with further changes. In addition, with the increase in organ discards, the committees should focus their work on improving utilization. Several members also voiced concerns about the attributes for pancreas allocation. The committees should focus on more on cold ischemic time and distance instead of prior living donor and pediatric pancreas transplantation. Both are very rare events in pancreas transplantation, and cold ischemic time and distance will have a much more profound impact on pancreas allocation. There was also concern noted for pancreas islet transplantation. Lowering the age and removal of local allocation is an extreme change to current policies, especially given that pancreas islets procedures are still awaiting FDA approval. The committees also need to clearly define if kidney/pancreas allocation will precede kidney alone allocation. Another member noted that in terms of kidney/pancreas allocation versus kidney alone allocation, the community needs to hear an update on the work of the OPTN Ad Hoc Multi-Organ Allocation Committee before Kidney and Pancreas Continuous Distribution gets too far along in the process. Lastly, a member expressed concern over DR antigen mismatches and suggested that the committees need to reconsider this in Continuous Distribution. In practice, candidates are routinely being transplanted with mismatched DR antigens, and giving points to DR matches may disenfranchise some populations.

OPTN Pediatric Transplantation Committee | 09/28/2022

The OPTN Pediatric Transplantation Committee thanks the OPTN Kidney and Pancreas Transplantation Committees for the opportunity to provide feedback on their Continuous Distribution of Kidneys and Pancreata Update. The Committee provides the following feedback: The OPTN Pediatric Committee supports the update from the OPTN Kidney Transplantation Committee and the OPTN Pancreas Transplantation Committee. The OPTN Pediatric Committee suggested the Committees consider how EPTS will be incorporated for longevity matching because that has not been applied to children before and was not developed based on any pediatric data. The Committee also expressed interest in the interaction between kidney-pancreas and kidney allocation because it may impact pediatric access to transplant. Additionally, the Committee supports the prioritization of pediatric candidates based on their age at the time of registration.

Loren Gragert | 09/27/2022

This update is very useful for understanding the attributes and parameters for scenarios that were ordered for the first round of discrete event allocation modeling in continuous distribution. I continue to have concern that the scenarios chosen for modeling appear to have such a drastically lower priority for the 99%+ cPRA highly sensitized candidates than we have in the current system. Without including scenarios with comparable or higher priority for sensitization relative to the current system, it may be difficult to interpolate the parameter values that will ensure equity across candidate sensitization levels for future rounds of modeling. Based on the 1-year follow-up after the proximity-based allocation changes for geography in 2021, we see that candidates who are 95-97% cPRA (and likely 98% as well) are clearly now receiving far more offers than everyone else, and I expect this is more than just a bolus effect. In the era of broader sharing, it seems that allocation points from cPRA for these 95-98% candidates give significantly more advantage than before. Furthermore, the allocation points vs cPRA value curve was not recalibrated to account for the geography-based allocation changes. I also advocate for models that would allow for ABO-compatible kidney allocation policy and use the ABO-adjusted cPRA metric to compute the candidate biology component of the composite allocation score, as described in our recent paper in AJT. At the Canadian Society for Transplantation (CST) meeting, my colleague James Lan presented some new modeling data from Canadian Blood Services that supported the hypothesis that ABO-adjusted cPRA would improve equity in offer rates among ABO blood groups and had a further benefit in increasing overall efficiency of allocation within their highly sensitized program (more HSP patients receiving compatible offers more quickly with the same number of donors). I’m excited to see the first round of modeling results from continuous distribution and we hope that the considerations mentioned above could be further examined in the next round of modeling.

Region 8 | 09/27/2022

A member suggested that this committee, and the other committees who are working on continuous distribution, need to take into consideration the growing challenges of aviation transport and limitations on transportation. A member reminded the committee that it is important to ensure that pediatric priority in the current system is retained. A member expressed concern for the low patient and general population feedback. The member opined that there seems to be a high percentage of medically urgent patients – and inquired if this has been reviewed since the new requirements for listing these individuals. The member also inquired how these changes effect patients who travel to multiple list. A member pointed out that there needs to be more long term data on organ outcomes with increased CIT, and whether this contributes to earlier graft loss. We need more long term data on organ outcomes with increased CIT. The member suggested to include projected cold ischemic time of organs as a factor in continuous distribution. A member suggested for the committee to consider something similar to liver allocation, where donors over age 70 are initially offered, locally, at first. A member inquired about the allocation monitoring, and asked what is the best way to interpret the results, and how are the results incorporated into the continuous distribution framework.

Association of Organ Procurement Organizations | 09/27/2022

Please see the attached comment from the Association of Organ Procurement Organizations


Region 7 | 09/27/2022

Members of the region are encouraged by the work on continuous distribution, and offered several things for the committees to consider as they move along with the project. One member expressed support that the committee is focusing more weight on placement efficiency and logistics for high KPDI kidneys which tend to be harder to place. Another member noted that highly sensitized candidate with cPRA in the 98-100% range have greatly benefited from changes in the current allocation system. Since the Kidney Allocation System implementation in 2014, it has also become clear that patients with 100% cPRA are heterogeneous. The precise cPRA is very informative for patients with 100% cPRA. It is important to model the new continuous distribution model and determine the effect of a new system on the sensitized candidate. Another member expressed concern with the increase in discarded pancreata as well as the number of times that there is no surgeon available to recover a KP, which they hope will be addressed in the new allocation system. Another member noted support in the work towards continuous distribution of kidneys and pancreata. The attribute weighting using the Analytic Hierarchy Process (AHP) was very good and allowed for empirical feedback. Now there is a series of factors to use for rating scales and weighting of patients. There was generally universal agreement in the ratings for both organs. The member supports the use of Review Boards for exception evaluation and the use of screening filters to reduce allocation time. Additionally, the member supports transitioning dual kidney allocation to the continuous distribution framework. Lastly, a member stated that this is critical work and a good step forward building on prior work of the committees. A composite multi-component score that is different between organs makes sense. In the modeling that was presented for KP/PA/PI only 2 models were considered. The member would encourage the committees to consider more modeling for KP/PA/PI. In regards to medical urgency, it appears the definition is 'soon to lose dialysis access". This is a rather subjective definition and a given patient may or may not meet the definition depending on the experience of the interventional nephrologist or vascular access surgeon and capabilities of the center. Also, in current practice, very few KP patients would meet this criteria, and more re-transplanted patients and those who have been on dialysis for a long time would be favored. Thus, the medical urgency population in part overlaps the sensitized population, who are already getting priority based on non-linear points for cPRA. It seems for pancreas, unlike kidney, there is no "medical urgency" component in the composite score. However, it is well known that diabetic patients have higher mortality on dialysis than non-diabetic patients, and therefore they might be deemed more medically urgent. The member is curious to see how this factor will be incorporated into giving them added priority (i.e. more points in the composite score). In the past for pancreas and KP recipients, only 4 points was awarded for high cPRA and none for low cPRA. The new continuous exponential increase in points for cPRA for kidney recipients in the new system is beneficial. Such a continuous system, rather than the binary system of cPRA should be incorporated into the new pancreas/KP allocation system. However, in the 1 year monitoring report of the new kidney allocation system, patients with a cPRA of 80-97% received an inordinate increase in access to transplants. Thus the math behind this allocation system should be adjusted in the new system to reduce the favoritism to these patients somewhat, not to eliminate their priority but to adjust the priority. Would the committee be willing to consider reinstating waiting time for a failed kidney after SPK if the kidney is lost in the first 60-90 days? DCD pancreata and SPKs should be utilized locally and regionally. These grafts are uncommonly utilized and additional cold ischemic time may not be tolerated. Thus, it is reasonable to favor local priority utilization for these DCD pancreata. Patient access is an important issue. Unfortunately, the OPTN does not quantify differences in offer acceptance rates for different centers. And transplant rates do not directly measure offer acceptance rates. It is indeed feasible to calculate offer acceptance rates for centers and this could be done fairly based on a subset of straightforward candidates. Once these values for each center are calculated, they should be used to upgrade/downgrade the patient access portion of the composite score for each candidate at the center in question. For example, centers with higher offer acceptance rates should have the patient access score upgraded slightly. This incentivizes appropriate utilization of organs. The member suggests the committee model this scenario. In the ratings for kidney and pancreas, there seems to be a category of "very nearby candidate". The rationale for this is unclear, what is nearby is rather arbitrary. It does not seem fair as a patient 50 NM away should receive no more priority than a patient 52 or 72 or 102 NM away. This flies in the face of medical urgency and equity. It is also counter to continuous distribution if a cliff at some "nearby" vs some farther away point. This system seems to potentially impact urban based programs more significantly than rural programs. It may favor very busy/active centers in urban areas whereby they would pull organs from nearby donor hospitals into their recipients disadvantaging smaller urban centers with fewer wait listed patients. Additionally, the details of the proximity efficiency scoring is unclear. Clearly there needs to be some proximity consideration and this should be greater for pancreas and KP than for kidney alone. Thus, the proximity score should have a steeper line/curve for pancreas than kidney. The member encourages the committees to strongly consider mandatory KP allocation for certain subsets of donors and to maintain a facilitated pancreas allocation system much like was adopted and subsequently refined by the pancreas committee. The committees should define how medical urgency will or will not be incorporated into a KP/pancreas continuous allocation system. This is not at all clear. How will post transplant patient or graft survival be incorporated? It is also unclear how candidate size is relevant to any equitable allocation system. While centers may take this into account, it is not clear how or whether it is sensible to incorporate this into an allocation schema. Still, allowing pediatric en bloc kidneys or pediatric en bloc kidney/pancreas transplants to occur as they have in the past would be useful. The concept paper is a testament to the complexity of these issues. The transplant community looks forward to hearing about the next round of analyses by the joint working group.

American Society of Transplantation | 09/27/2022

The American Society of Transplantation (AST) generally supports the concepts reviewed in this paper. This paper aligns with the recent National Academy of Science, Engineering, and Medicine (NASEM) report, "Realizing the Promise of Equity in the Organ Transplantation System,” and the AST agrees a flexible and uniform approach to organ allocation that is driven by machine learning algorithms and historical data is needed. The AST offers the following comments for consideration as this work continues: •The community should have confidence in the ability of the models to reliably and reproducibly predict actual allocation outcomes based on weighting of different variables. C-stats of these models should be provided; if actual outcomes cannot be reliably modeled, the rest of this discussion is theoretical.  See also •This proposal would benefit from a monitoring plan, including a data analysis schedule, specific metrics, and more information about how this model will adapt and be adjusted over time. •Hard to place, dual, and en-bloc kidneys should be allocated in a way to decrease cold ischemic time and preferentially offered to the centers with history of accepting such organs. The “preferential status” can be changed every 6 months based on center behaviors. •We support the mirror approach to longevity matching in continuous distribution. •We agree with the re-evaluation of how much waiting time should be weighted in the new framework. •In general, we support the idea of waiting time inversion but this needs to be studied further and more granular data is needed to fully assess the impact. •Addressing racial, geographic, and other inequities is of paramount importance. Mechanisms aimed at improving access and outcomes for currently disadvantaged populations should be a focus and included in early iterations of this project.


Region 11 | 09/26/2022

An attendee stated that this works fine for kidneys everyone would use but doesn’t work at all for marginal donor kidneys. Another attendee proposed using projected sequence of acceptance as a measure of efficiency of the system. Another attendee stated that efficiency should also be measured by using offers made after final acceptance where no transplant occurred.

Gift of Life Donor Program (PADV) | 09/26/2022

Gift of Life Donor Program (PADV) appreciates the opportunity to provide public comment on the Kidney and Pancreas Transplantation Committee’s “Continuous Distribution of Kidneys and Pancreata Update” and we support efforts towards a fair and equitable system that promotes equal access for all transplant candidates. Recent UNOS data shows discards for both pancreas and kidneys have increased across all donor types since the implementation of the new kidney allocation policy in March of 2021. This update does not include any new elements that will increase kidney or pancreas utilization. Increased utilization of deceased donor organs should be considered in any new allocation policy. This update does not address the well-established and known challenges previously shared by OPOs and Transplant centers. There is still only consideration given for distance from donor hospital. However, placement efficiency must also consider: the numbers of centers an OPO will need to interact with to achieve acceptance, the amount of time to identify final candidates, amount of time after cross clamp to achieve acceptance of kidneys and cost to ship. This is especially important in more densely populated areas. Impact will vary in different parts of the country. For example, in the mid-Atlantic region the current sharing radius could include up to 12 donation service areas and as many as 60 kidney transplant centers. Better data is needed to look at efficiency in the system, not just distance. Since implementation of the new kidney policy in March of 2021 OPOs and transplant centers have faced increased administrative burdens: more interactions, more offers and more calls per donor often resulting in fewer transplants. Many transplant centers have contracted with third party services to take organ offers and serve as the liaison with OPOs. This has created challenges for OPOs who now must interact with additional gatekeepers who often refuse to evaluate the offer, talk to the decision makers, confirm patient readiness, or perform a final cross match until they are primary and/ or all recovery information is available. Furthermore, these centers and/or their services then take 30 minutes per candidate to accept or refuse the offer. This adds significant cold ischemic time to a kidney, particularly when the kidney is declined for donor information known hours or days before procurement, but the center(s) failed to evaluate the offer when notification was made via DonorNet and simply entered a Provisional Yes and did nothing else. This forces OPOs to move to expedited placement after recovery to ensure these precious donated gifts are used. We attribute our success in increasing kidney utilization to our long standing, well proven, hardwired best practices in kidney allocation and believe these rules should become UNOS policy for kidney allocation. Including requirements for transplant centers to fully evaluate primary and back up kidney offers pre-recovery, determine recipient appropriateness, complete a final cross match (all kidney centers should have the capability to perform virtual cross matching to reduce need for sharing donor blood prior to recovery), ensure patient readiness & availability, and commit to accepting a kidney with acceptable intraoperative findings. Every kidney donor should have at least 5 potential candidates identified prior to organ recovery. When centers refuse to consider an offer until all intraoperative information is available, cold ischemic time increases and OPOs have trouble in completing sequential allocation. Well defined rules and definitions on the requirement of transplant centers to respond to pre-recovery offers, and transplant center responsibilities during the allocation and acceptance process must be included in policy. The released organ policy should be updated to include a requirement of accepting transplant center identify and prepare an appropriate back up patient at time of kidney acceptance. The AHP exercise, while an effective way to solicit feedback for the prioritization of candidates on the match run, implies that the kidney being offered would be desired by all candidates on the match run and seeks to identify the most appropriate candidates. It overemphasized a very small number of patient classifications, for example, it is rare to see a medically urgent kidney patient listed on a match run. It also fails to consider how kidneys from medically complex donors should be allocated nor does it consider how far a kidney might have to travel between donor hospital and transplant center, the impact of cold ischemic time or the number of candidates/centers a kidney is offered to prior to acceptance. While the AHP exercise results placed a low priority on distance and allocation efficiency, the reality is that kidneys are frequently turned down by centers for actual or anticipated cold ischemic time. Placement efficiency must be given a greater weight for the allocation of higher KDPI kidney donors (>/= 60%). For these kidneys, placement efficiency should be given a weight of at least 50%. We have already strained the existing courier infrastructure and for kidneys that would require air transportation, we are reliant on an unreliable system, which is severely encumbered by limited commercial flight options, cancelled flights, existing commercial airline cargo rules and timing restrictions. There is no national system for sharing organs via commercial airlines, nor any accountability for commercial airlines to care for this precious gift. Kidneys should be placed within a drivable distance when possible. Continuous distribution without careful consideration of efficient practices and proximity between recovery hospital and transplant center will only exacerbate the transportation deficiencies that already plague the current allocation system. Gift of Life is supportive of the continuous distribution model; however, we do not support many elements in this update. More consideration must be given to placement efficiency and any policy must include a pre-recovery commitment on the part of transplant centers to fully evaluate the offer, check & medically clear their candidate(s) and perform a final cross match on the top 5 sequential candidates. Additionally, the model must place an even higher weight to placement efficiency of higher KDPI kidneys (>/= 60%). OPOs continue to ask for tools and resources from the OPTN to ensure efficient allocation and increased utilization of deceased donor kidneys and pancreata. These tools need to be made available to OPOs prior to the implementation of a continuous distribution policy. Additionally, modeling and test match runs are needed to fully understand the impact to allocation.

Anonymous | 09/26/2022

I participated in the Analytic Hierarchy Process this spring and I think it gave a decent idea of what we should be prioritizing as we develop the Continious Distribution framework and attribute weights. However, I did find some flaws with the exercise. While do support increased access for hard to match patients, including ABO and HLA compatibility, I worry that by giving extra weight to those candidates, we may end up prioritizing candidates who are on there second or third transplant. Additionally, I found it impossible to ethically choose someone who was a "extremely nearby candidate" over any of the other options during the exercise. However, while that may be the moral option, logistics don't always agree with our morals. I think it would be educational for the committee to look at the match runs for organ donors originating in Montana, especially Central and Eastern Montana. Because there are no transplant centers in the state of Montana and there is only one transplant center within 250 NM of parts of Western Montana, donors originating in that stat have effectively been testing out a national distribution scheme. While I realize that there may be different lists following the Continuous Distribution change, it would be useful to see what kind of logistical difficulties and declines due to ischemic times there have been under the current protocol.

American Society of Transplant Surgeons | 09/26/2022

The American Society of Transplant Surgeons (ASTS) is pleased to provide the following feedback for the OPTN Kidney and Pancreas Transplantation Committees on the Continuous Distribution of Kidneys and Pancreata Update. When considering the current 250nm sharing circles, it must be noted that the two proximity points are unnecessary in this circle and tends to hamper transplants to rural patients listed at their nearby rural transplant centers—that is, further from the busier urban trauma donor hospitals. ASTS believes we have moved too far away from allocating with a major importance on the longevity of the transplant survival. This will only result in need for re-transplant in the near future. We believe that we need to balance this with the post-transplant survival metric as an overall system goal. Putting a great deal of emphasis on highly sensitized candidates generally leads to more re-transplants and a shorter graft survival. Additionally, prior living donors should have rapid access to transplant, if required. This is a cornerstone of our living donor efforts that may result in many more transplants than deceased donor organs utilized for this prior living donor population. Highly sensitized patients have been given unfairly rapid access to transplant with known decreased long-term survival. Patients with CPRA < 99.9 should no longer be at the very top of the allocation list as their time to transplant has been shown to be much shorter than the average patient. The increased allocation points were created to make access fair and equal, not to overly advantage higher CPRA candidates. Highly sensitized patients should not have access to top 20% KDPI organ donors unless they have an EPTS in the top 20%. Additionally, we urge the Committees to include a discussion on equity of access for those awaiting their first versus subsequent deceased donor organ. Specific Comments to Continuous Distribution Committee Update Table 1: Kidney 3rd row: ASTS would agree with some sort of continuous longevity matching using KPDI and the unabridged EPTS. 4th row: Blood Type: please remove the current unfair advantage of Blood Type B candidates listed for non-A1 donors. These B candidates should simply be intermixed with the A candidates, not put at the top of the A list. We believe your newly proposed point system for B candidates who can access non-A1 donors should do this. KAL safety net: ASTS agrees that safety net patients should have access to top 20 KDPI only for those with EPTS in top 20%. Last row: ASTS would suggest no point difference within the 250nm initial allocation circle, that is, all points receive the same number of proximity points. Between 250 and 500nm, the ASTS would support a slope down to 25%, with a gradual slope out from 500nm. Table 2: Pancreas, KP, Islets Proximity Efficiency: we would suggest no point difference within the 250nm initial allocation circle, that is, all points receive the same number of proximity points. Between 250 and 500nm should be a second set of similar allocation points, then no additional points outside of 500 nm. Medical Urgency: All candidates listed for Medical Urgency must have documentation completed before being granted such status. The Kidney Committee should set an upper limit of expected Medical Urgency Candidates a year (example 0.5% or less of waiting list). Programs that list more than this number should have all listings reviewed. HLA Matching: IF DR matching does not limit access to minority populations, then DR matching should be encouraged due to increased longevity of grafts and decreased sensitization. ASTS agrees with a continuous KDPI and EPTS allocation system. We understand that actual curves have not been created. We would support that Top 20% KDPI curves highly prioritize Top 20% EPTS candidates and perhaps give some access to Top 21 to 40%, but no access above EPTS 40%. KDPI over 75% should be the reciprocal of the Top 20% KDPI organs giving preferred access to EPTS above 80 candidates and then to 61 to 80 EPTS candidates. The extended EPTS scoring system from the original LYFT simulations will likely need to be used with more variables to differentiate the over 20 EPTS candidates. ASTS agrees with simply giving pediatric candidates low KDPI values. From numerous publications, many pediatric graft losses are due to non-compliance, so an accurate EPTS will likely be difficult to construct with acceptable variables. CPRA: ASTS would like the Kidney Committee / SRTR to closely look at the high amounts of CPRA points given to those with CPRA > 90 and < 99.9%. There appears to be an unfair rapid access to patients receiving more than a couple of CPRA points with the larger 250nm circle as the number of available kidneys is now greater for initial level of allocation. The CPRA scale should be created to allow equal access, but not more rapid access for sensitized patients. Pediatric priority: We caution the Kidney Committee not to encourage the use of less optimal donor grafts (KDPI over 35%) for pediatric candidates. It is truly rare that with the current 250nm circles, a pediatric candidate does not receive a Top 35% KPDI offer within a reasonable time frame (unless highly sensitized). For centers who believe they are not receiving offers, they should review the offers with their team. ASTS agrees with waiting time being kept linear throughout and not making it unnecessarily complicated. We agree with keeping waiting time accumulation starting at eGFR 20 ml/min pre-dialysis as incentive to refer early for transplantation which may increase living donor transplant options. KAL: ASTS agrees with access to Top 20% KDPI organs for candidates with EPTS Top 20%. Proximity Efficiency: ASTS would suggest no point differential for sharing within 250nm of the donor hospital as this is usually the distance for driving compared to flying for longer distances. Giving points within the 250nm circle, such as within 50nm simply advantages the transplant centers closer to the trauma hospitals, and unnecessarily disadvantages patients and transplant centers in more rural areas that are still within driving distance of the donor hospital. The few hours of driving add very little to the cost of transportation or to the CIT, has no impact on graft survival, and was not supported by the AHP exercise. The proximity points within a 250nm area only serves to disadvantage those who live further from trauma/donor hospitals and wait longer than those patients whose transplant center is closer to the donor hospital. This can result in an outcome that favors patients who have the means to drive further to large metropolitan hospitals to gain waiting time points over those who are forced to stay at their nearby transplant center that may be rural. (An example of this is the waiting time differential for patients at Augusta Health (MCG) compared to the Atlanta centers which are closer to the major trauma/donor hospitals.) For higher KDPI organs, more efficient placement will likely occur if you limit the number of patients who can be listed by a center for high KPDI organs at any one time, so the centers have more incentive to use the higher KPDI organs into the appropriate patients on their waiting list. Again, giving large number of points to centers nearer the donor hospitals will give these centers’ patients an unfair advantage over rural hospitals’ patients. En Bloc kidneys require much more work effort and skill to implant with a higher risk of thrombosis. The KDPI should be set to reward, not punish, utilization of these organs giving transplant centers some leeway for increased risk of thrombosis. Released organs: First, the definition of a ‘released organ’ is not very clear in the document provided. Please provide a clear definition. It appears to be a declined organ once the organ has already arrived at a transplant center. If this is the definition, then proximity points for efficiency of placing released kidneys should be based on KDPI and time from crossclamp as lower KDPI organs are usually easy to place.


Region 1 | 09/21/2022

An attendee commented that modeling results will be important to provide a sense of what these options may yield. An attendee suggested that the first iteration should be simple and then be adjusted. Another attendee recommended that as we talk about sharing kidneys more broadly, we need to recognize the impact of cold ischemic time. Another attendee commented it might be useful to at a prioritization category for patients will to accept a "marginal offer". This may improve system efficiency.

Region 3 | 09/20/2022

The attendees were generally supportive of this project. One attendee commented that the committee should discuss whether to use the donor hospital or the recovery center when weighing placement efficiency. They added that if it is based on donor hospital, it will disadvantage rural centers. Another attendee commented that the committee needs to consider how the system will take into account the distance/geography of Puerto Rico and consider a variance that would protect quality. One attendee suggested that the committee consider cold ischemia time from cross clamp to arrival at the recipient center for kidneys since they travel via commercial airline and courier. Another attendee commented that cost, recovery rate, complexity, discard rates and transplant rates/cold ischemia time all need to be considered when moving toward continuous distribution.

Anonymous | 09/14/2022

Since the implementation of the new allocation platform for kidneys and pancreata, we have have some frustrations getting blood for cross matching prior to cross clamp and procurement of the organs. We are in San Diego and are frequently being offered organs from Los Angeles. Our experience has been that if we are ranked 1-3 and request blood, we are often times told that there is no blood available (H&H too low) and when we look at the crossmatch list on UNET, there have been 10-14 candidates crossmatched (below us). I feel that this is a disadvantage to our candidates and increases cold ischemic time when it can be avoided. Thank you for hearing my concern.

Anonymous | 09/14/2022

The public comments regarding Continuous Distribution (both the original comment period and now this update) offer immense amounts of insight from different classes of stakeholders. What stands out most in these comments is the in-depth knowledge that each stakeholder has in his or her area of expertise, but it’s also clear that most of us predominantly know only our own area of expertise (based on lack of comments about other areas, or comments that are contrary to my own experience/knowledge/opinion). Many of the comments bring up important considerations that were poorly addressed or not addressed at all in the allocation exercise, which ultimately was too simplistic to produce any useful information about the relative importance of the various allocation criteria. The imbalance between patients waiting for a kidney transplant and the number of available kidneys means that many patients will die waiting for a transplant. On our waiting list 30% of the candidates leave the waiting list (die?) without receiving a transplant. Rather than looking at this problem from the standpoint of which patients should be prioritized for a transplant, perhaps we should look at it the other way around – which patients are we most comfortable with allowing to die while they wait for a transplant? It’s a starkly morbid but not inappropriate question. The deaths of patients on the waiting list that bother me least are those patients least likely to have a long life after transplant, which puts “Excellent Longevity Match” at the top of my list of allocation criteria. For the other allocation criteria, medical urgency, prior living donor, and kidney-after-liver involve so few patients that any points for those criteria are of little concern. Biologically-difficult-to-match patients and long-waiting-time patients overlap to a significant degree – they should be combined into a single waiting time criterion but with a steep non-linear curve rating. “Excellent Longevity Match” covers the ethical concern of utility, and “Waiting Time” covers equity. “Proximity Efficiency” (misleadingly termed “Nearby Candidate” in the allocation exercise) doesn’t necessarily fall under either ethical concern, but is a matter of practicality, and still requires serious consideration in allocation, as the inefficient allocation that inevitably comes with more distant allocation leads to a decrease in utility.

Region 2 | 09/13/2022

Several members expressed support for the direction of the project and it was noted that the project seems to be trying to balance equity and utility. One member stated that the current discard rate is extremely concerning and should be a top priority in Continuous Distribution. Another member noted that the committee should consider medical urgency on a scale compared to the current binary indicator. Additionally, in the context of placement efficiency, the committees should consider the number of programs and/or patients within a given distance versus distance alone. Another member noted that as allocation moves to Continuous Distributions, EPTS has not been a good indicator of predicting post-transplant survival for pediatric patients. Lastly, another member commented that inadvisability of 250 NM local sharing in the densely populated mid-Atlantic region, where over 25% of the US population is concentrated, whereby over 60 transplant centers appear on many match runs was ignored in the current iteration of kidney allocation. Failure of the allocation scheme to make allocation practical for the OPO's leads to long cold ischemic times and too many organs allocated out of sequence, as late offers, open offers, and offers to any center that will accept. The continuous distribution concept, if it is to work, must be used to increase the importance of efficiency in allocation by increasing the value of short distance in a non-linear fashion, respecting the difference between driving short distance, driving extended distance, and the inefficiency and inappropriateness of using commercial aircraft for organ transportation.

Region 9 | 09/12/2022

One attendee commented that there should be standardizations around hard to place kidneys. Another attendee supported the continuing efforts to move toward continuous distribution but opined that more data analysis and modeling are needed to address this complex topic. One attendee commented that utilization of pancreata and SPK is critical and should be considered as unique and outside of standard allocation. They went on to provide an alternative where a Type 1 diabetic with a living donor could get priority for an SLK if their donor donated to a non-diabetic on the deceased donor list. Several attendees commented that they supported continued efforts to move allocation toward continuous distribution.

Region 5 | 09/08/2022

A member expressed concern that there should be more input from the general public and that the majority of the feedback, to date, is from transplant professionals. The member believed that if there was more feedback from the general public then wait time would be ranked higher. A member suggested that current policy has resulted in a higher rate of kidney discards and opined whether that is cause for concern. A member asked for clear guidance and/or policy regarding expectations related to kidney and pancreas continuous distribution. The member explained that transplant centers will need to prepare for more offers, and to accept and process early cross-match specimens early (not just post-cross-clamp). Further, OPOs will need a process to handle late re-allocation of kidneys and (perhaps) pancreata. A member supported this update and stated that the process to define weight attribute is vague. A member supported assigning distance parameters based on the geography of the region (i.e. larger distances between transplant centers in the Southwest warrants broader inclusivity in allocation compared with regions where transplant centers are geographically closer). The member said that kidney and pancreas continuous distribution is broadly supported in the region. A member stated that it is important to ensure that pediatric candidates are considered in simulation analyses so impact on pediatric transplant and allocation is reasonably understood.

Anonymous | 08/30/2022

Organ travel time, and specifically Cold Ischemic Time, is a big factor when transplant centers are determining organ acceptability. Making estimated CIT clear to transplant center coordinators when reviewing offers may help expedite the decision making process. Additionally, making the weight of the attribute associated with CIT (placement efficiency?) inversely related to population size of the metropolitan area the organ is being allocated from may help overcome transportation infrastructure hurdles. This would prioritize 'local' placement of kidneys in situations where they are being allocated out of smaller cities with less of an ability to transport the kidney large distances quickly. Likewise, when a kidney is allocated from a large metropolitan area with more transportation options, it would give greater access to individuals farther away.

Anonymous | 08/29/2022

New allocation policies limit access to kidney transplantation for individuals living in states without a transplant center. Those states include Idaho and Montana. The allocation policy made adjustments for residents of Alaska but did not make similar adjustments for Idaho or Montana.

Anonymous | 08/28/2022

Being a Type I diabetic my entire life (57 years), I need a new pancreas to stop the extremely low blood sugars which I do not feel - but my kidney function is too low, my GFR ranges between 27-35 (My GFR appears higher because I am retaining massive amounts of fluid, so they are unable to get an accurate reading). I have serious complications from the diabetes, heart, stomach, low RBC, uncontrollable blood pressure, weakness, thyroid, etc.. I am stable enough now for transplant, but Mayo will not list me because my kidneys are not bad enough (Mayo says my GFR has to be under 20). The longer I wait, the less likely I will ever be able to be transplanted. Doctors agree once I'm transplanted, my stomach, heart, eyes, thyroid will improve. I am in a black hole in between and meanwhile, suffering - UNOS should have a plan for folks in my situation. Please establish best practices for those who need a multi organ transplant but are prevented because their kidney function GFR has not reached under 20 and/or the facility is unable to get an accurate reading due to severe edema from the poor kidney function..

Region 4 | 08/26/2022

Comments: One attendee suggested the proximity weight for kidneys could be based on the average amount of cold ischemic time from cross clamp to arrival at the recipient center. This would be different than other organs due to kidneys being transported via commercial airlines or couriers if not accepted by centers close to the OPO. Another attendee encouraged releasing data early after implementation to dispel any myths about the data, facts and numbers.

Carlos Marroquin | 08/18/2022

Improving the allocation and utilization of pancreata and specifically SPKs is critical. These are underutilized resources. When we think of the overall ranking of candidates for an SPK. Could we entertain a unique condition? This condition would provide an opportunity outside of the standard allocation but would have the capacity to improve overall outcomes to all involved. That condition being when a type I diabetic has a live donor option. What if their donor donated to the next well matched non-diabetic candidate on the list and in turn, the type I diabetic receives priority for the next available, well selected age matched SPK.? This would have the greatest impact for everyone involved. We know the live donor kidney would have a better outcome in a non-diabetic and the type I diabetic would have a better outcome from the combined SPK. Both the kidney and pancreas allograft survivals are improved in the SPK over a kidney (whether cadaveric or live donor) followed by a PAK. There is a lot of data for the superiority for SPK over any other transplant involving a pancreas. Review hans Sollinger in Ann of Surg 2009. “One thousand simultaneous pancreas-kidney transplants at a single center with 22-year follow-up”

Harvey Solomon | 08/11/2022

I submit that distance is not the critical parameter but rather estimated CIT. Kidneys are transported either by ground or commercial flights.. Incorporating estimated CIT would contribute to better post-transplant outcomes and reduce discards.

James Sharrock | 08/11/2022

I’m watching the presentation on this project at the Region 4 meeting. As I do every chance I get, I encourage the Kidney and Pancreas Committees, and all committees working on continuous distribution projects to abandon the the term AHP and the phrase it stands for and replace it with “values exercise” or a similar term. Neither transplant professionals, not patients, nor the general public understand what AHP means. We are trying to determine what community values are with respect the the priorities of the identified attributes. Let’s say that in our presentations and discussions.