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Update on Continuous Distribution of Kidneys and Pancreata

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Background

In December 2018, the OPTN Board of Directors approved the continuous distribution framework for allocation of all organs. Continuous distribution will rank waiting list candidates based on points related to various factors, such as medical urgency, post-transplant survival, candidate biology, patient access, and placement efficiency. Continuous distribution will remove the hard boundaries built into the current framework to increase equity for patients and transparency in the system.

This concept paper provides an overview of the project’s development process and progress, and offers next steps for continuous distribution of kidneys and pancreata. The paper also requests community feedback that will assist the Kidney and Pancreas Committees’ work.

Supporting media

Presentation

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Progress so far

  • From September 2020 – January 2021, the Kidney-Pancreas Continuous Distribution Workgroup worked to identify goals and key attributes related to kidney and pancreas transplantation.

Proposed concept

  • Continuous distribution will replace the current classification-based allocation system with a points-based allocation system. A points-based framework assigns a composite allocation score to each candidate.
  • A candidate’s composite allocation score will determine the order that organs are offered to candidates. 
  • A candidate’s composite allocation score will consider a combination of donor and candidate characteristics including candidate medical urgency, post-transplant survival, candidate biology, patient access, and placement efficiency.

Anticipated impact

  • What it's expected to do
    • Provide a more equitable approach to matching candidates and donors.
    • Remove hard boundaries that prevent candidates from being prioritized higher on the match run
    • Establish a system that is flexible enough to work for each organ type
  • What it won't do
    • This paper is not a proposed policy change, but will help the Kidney and Pancreas Committees develop a future policy proposal.

Themes

  • Proposed attributes for the composite allocation score
  • Additional attributes that should be included
  • Weight of attributes in final composite allocation score
  • Best ways to convert current system into points-based framework

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.
  • 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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Provide feedback

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OPTN Organ Procurement Organizations Committee (OPO) | 09/24/2021

The OPO Committee appreciates the opportunity to provide feedback on the Kidney and Pancreas Transplantation Committee’s concept paper on Continuous Distribution of Kidneys and Pancreata and provides the following comments: One member recommended utilizing longer term outcomes than one-year post-transplant survival, particularly in terms of optimizing allocation for kidney and pancreas recipients. A member remarked that there should be a way to factor in hard to place kidneys, such as a prioritization that takes into consideration the centers accepting and transplanting these organs so that utilization can be improved would be impactful. The member added this is not only helpful to recipients, but to donor families as well, particularly for very young pediatric donors. One member shared that the recently implemented circles-based kidney allocation system has exponentially increased transactions with transplant centers and significantly stressed transportation systems. Transplant centers are increasingly using third party services to receive organ offers, leading to increased inefficiency. The member continued, noting that under broader sharing, there have been upwards of 6000 candidates in the 250 nautical mile (NM) circle on the match run. It is almost impossible to get through that many candidates in an equitable manner efficiently. The member concluded that OPOs need support from transplant centers to more efficiently allocate kidneys, and that DonorNet is inefficient. A member shared that their center has seen significantly reduced kidney offers since implementation of the circles-based distribution, and recommended adding some kind of recognition for veterans as an attribute. The member also noted that their military education is not appropriately considered in the demographic data collection for waitlist, and suggested including demographic questions for military service. The member explained that there should be some kind recognition for veterans with exposure to agent orange and other warfare chemicals, so there is some recognition of why these patients need transplant. One member commented that the hard boundaries aren’t serving patient populations well, particularly the use of nautical miles and the 250NM then national placement boundary. The member continued that education would be critical for patients, and added that there are barriers to broader sharing in differences in practices between transplant centers and inefficient courier systems. The member provided cross-matching as one such example of differing transplant center practices creating inefficiencies. Some centers will do retroactive and virtual cross matching, while others ask for blood samples. As an OPO, only so many donor blood samples can be taken and shared. The member remarked that these kinds of practices should be considered when potential recipients are from so many different transplant centers. Another member agreed that the blood sample issue is an obstacle to efficiency, particularly with unpredictable couriers. The new policy could build something in that would set a limit on the number of blood samples OPOs would be required to send. The member commented that prioritizing virtual crossmatch could be impactful, particularly investing in the knowledge and research required for virtual crossmatching on the transplant program side. A member shared that for efficient management of kidneys, pre-recovery focus in allocation is on equity and fairness, and following the match run. Transplant center behavior varies in terms of serious offer evaluation. Post-recovery, however, the member shared that after 5 or 6 transplant centers decline a kidney for all their candidates, the kidney can become difficult to place. The member continued that these allocation policies will increasingly push OPOs to expedite allocation post-recovery, simply because the volume of patients on the match run is too large. Particularly, transplant centers waiting until they’re primary and taking the full hour to evaluate, and then declining, increases the cold ischemia time on marginal kidneys, reducing their chances of placement. Another member commented that the idea of building in a way to prioritize centers that accept marginal kidneys would be very helpful. The Pancreas Committee Chair also noted that most of the continuous distribution discussion has focused on pre-procurement, and that the feedback to acknowledge and discuss post-procurement is very helpful. One member recommended a dynamic match run that adapts and prioritizes as an organ approaches cross clamp time or as cold time increases, so that there is more weight towards efficiency at a critical point to avoid organ discard. The member also noted that pancreas allocation has become more like liver allocation in terms of transportation timeframes, and recommended thinking about proximity points differently with pancreas and kidney-pancreas versus kidney alone. A member shared that circles-based geography presents its own inequities – the Pacific Northwest has a quarter of a circle and a sparse population, while Nashville has a complete circle in the middle of the country. The member continued that their centers have lost a large geographic area in the circles-based distribution, and that geography is not appropriately weighted. The member recommended that geography be considered as an area, rather than a line or a circle. One member recommended that the need for more air transportation, from a systems perspective, needs to be considered in broader allocation of kidney and pancreas in order to avoid increased discards.

Region 1 | 09/24/2021

A member commented that the ability to adjust the attributes in continuous distribution more nimbly is a major benefit of this system. One attendee mentioned a center’s acceptance of hard to place kidneys as something that the committee might consider while developing continuous distribution. A comment was made regarding the committee reviewing the current sliding scale of points for cPRA, especially those in the range of 90-96, to determine if the points reflect the true biological need of the candidate. Another attendee, referencing the age of recipients and the benefit they receive from transplantation, asked if the committee could consider more nuanced ways of weighting age of a recipient than EPTS. Another member stated that this process would benefit greatly from continued engagement with the community through more group discussions with an adequate amount of time allotted. A comment was submitted that the individual would like to see more data to confirm that continuous distribution will produce meaningful results.

American Nephrology Nurses Association (ANNA | 09/23/2021

ANNA supports

Attachment

Region 6 | 09/23/2021

An attendee appreciated the inclusion of pediatric considerations. Another commenter noted the workgroup may identify groups who are waiting for single kidney that need to be prioritized over multi-organ transplants. An attendee recognized the workgroup’s efforts to increase equity and access, but noted the ideas being discussed only seek to increase fairness for patients on transplant lists. The attendee added these concepts won’t help patients in areas where there is poor access to healthcare, and there needs to be advocacy for these populations. An attendee stated the OPTN should implement the recommended changes quickly.

Region 8 | 09/22/2021

Region 8 generally supports the progress of this update with the following feedback for policy development. A member pointed out that it is important to consider how donor biology will play a role moving forward, especially with pediatric candidates and that there needs to be consideration for pediatric prioritization. A member pointed out that this concept caused his institution to revisit concerns raised during the development of the lung continuous distribution. These concerns are: removal of separate allocation policies based on organ classification (here it is based on KDPI, in the lung policy it was adult vs. pediatric organs), and incorporation of a pediatric population that does not currently have survival models into an allocation scheme that includes them. A member stated that his institution supports this proposal overall but stated that there needs to be strong consideration on the ease of implementation for OPOs and transplant centers. This change will have major impacts to on-call requirements for transplant programs. Further, it is essential to consider ease of delivery of organs to the transplant center and potential increases to cost. A member pointed out that on the OPTN website presentation it was stated that "continuous distribution will provide organ offers to the sickest and best able to benefit from the transplant". Then the member asked, that based on the CAS, how is "sickest" defined since many factors are included in the CAS? Further, how will the current EPTS and KDPI systems be integrated into the continuous distribution framework (e.g., longevity matching). And will donors have a CAS also? The member suggested that there needs to be parity between quality of the donor offer and the candidate survival expectation for best use of the donor gift. A member stated that his institution respectfully asks the Committee to consider a factor for "rurality" of transplant programs as it considers kidney and pancreas allocation. The distance from procurement site alone does not consider commercial flight availability for the more rural transplant centers and the impact that may have.

Transplant Administrators Committee | 09/21/2021

The Transplant Administrators Committee (TAC) appreciates the opportunity to comment on this concept paper, and thanks the Kidney and Pancreas Committees for their work. A member said it is hard to comprehend how the composite allocation score will work for kidney since kidney candidates are not necessarily facing the same time constraints as a heart, liver, or lung candidate. TAC supports continued consideration by the Kidney and Pancreas Committees on how dialysis will factor into the composite allocation score, including how time on dialysis impacts individual patients. Additionally, a member suggested that the committees consider the administrative burden of tracking and reporting data related to the medical urgency attribute for kidney.

Region 7 | 09/15/2021

Comments: There was robust discussion during the meeting regarding CAS, KPDI, and SPK candidates. Several attendees voiced support for the CD framework. An attendee asked about the availability of data to assess pre-transplant mortality risk for solitary pancreas transplant candidates. Others expressed concern that there is the lack of literature to be able to establish a defined way to compare waitlist mortality and medical urgency for a solitary pancreas recipient to that of an SPK recipient. One attendee had concern regarding prioritizing the sickest patients as kidney/pancreas patients who are very sick and likely will not be able to undergo surgery and survive. Some attendees expressed the possibility to quantify hypoglycemic unawareness as an aspect of medical urgency for pancreas recipients. An attendee also asked the committee to consider how to mitigate inefficiencies and model the impact of continuous distribution on organ donation and especially cold ischemic time and discards. There was feedback on how this will impact pediatric patients. Specific concerns included how age will be considered, the priority accorded for dialysis time, priority for patients over age 18 who were listed before their 18th birthday, the types of kidneys (by KDPI or otherwise) that would be offered to pediatric patients and their priority for those kidneys, and how multi-organ and pediatric patients will be prioritized. There was also concern that CD should be carefully modeled to assess the impact on pediatric patients prior to implementation. One attendee also commented that protection for pediatric candidates should be underscored.

Region 9 | 09/14/2021

Members had several comments and feedback for the committees. One member commented that the timeline for this project seemed long and suggested doing whatever possible to expedite it. Several members voiced support for the project overall. A member commented that they hoped the cPRA scale will be more gradual and not jump up so severely at 98%. A member noted that determining the extent of non-primary organ offers to improve allocation efficiency and transplant center unnecessary work burden was needed. One member also remarked that there is much more work to be done on this project.

Region 3 | 09/10/2021

Many attendees had feedback for the committee and provided the following comments. KDPI is a poor predictor of organ quality. Will the committees try to come up with a better metric? The committees should ensure pediatric candidates registered before age 18 maintain priority with the transition. Organ offer filters should be equivalent to an organ refusal, and there should be no advantage for programs to use several organ offer filters. They are effectively preset criteria for refusing an organ sight unseen. It is difficult to get centers to accept KPs, particularly when cold time is increased due to transportation limitations. Commercial air is an OPO’s main, and sometime only, option. Issues with timely transportation need to be taken into consideration throughout the country, not just on the East and West coasts.

Region 2 | 09/10/2021

• Comments: Members of the region had a fair amount of feedback for the committees to consider as they progress with their Continuous Distribution work. It was noted that in service of ethics and efficiency, the committees should prioritize appropriate KDPI/EPTS matching in the evolving allocation system over a simple de-prioritization of patients with higher EPTS scores. If an older/higher KDPI donor is offered, perhaps additional consideration should be given to higher EPTS potential recipients on that match run to maximize organ and recipient survival parity, and thus efficient organ usage. If higher EPTS patients are de-prioritized regardless of the nature of the donor organ being offered, it will medically disenfranchise a large number of the patients we serve. It was also noted that the concept paper suggests that the current system would be changed from a timed system to a points system. This is somewhat disingenuous because points are certainly used in the current system. A future proposal could be strengthened if the hard boundaries that are referenced were clearly depicted in a few allocation runs. Members expressed concern about the increased number of organ offers seen with the newly implemented kidney and pancreas allocation policies. Moving forward the committees should consider ways to improve efficiency of organ allocation. One member noted that geography should have more points than proposed for lungs - it should account for at least 25% or more. Utilization, cost, and outcomes should be evaluated frequently and determine if improvements need to be made. In terms of efficiency, a member noted that donor assessment would be more fluid in a Continuous Distribution system. Another member questioned whether it is necessary to provide prior living donor points for pancreas candidates, since that would be a very rare occurrence. It was also noted that pediatric patients have a lot of years ahead of them and offering them points for best matched kidneys would help prolong their allograft lives and prevent sensitization to some extent. Another member noted that it would be more equitable to reconsider the pediatric designation to a youth designation and that for certain very young adults the allocation should gradually move down a scale as they age into more mature adulthood, perhaps with the scale ending at 25 years old. Lastly, patients at rural programs are disadvantaged by distance to a transplant program, but additionally, the program's distance and access to receiving shipped kidneys. Shipping distance may magnify CIT for rural programs due to logistical concerns. For example, rural kidney programs may not have close access to their own OPO where kidneys are pumped or biopsied. Rural centers may also have distant access to large airports that are utilized for shipping kidneys. With the new allocation system, kidneys are delayed by an additional 12 to 18 hours based on lack of flights. The member urges data collection, and eventually, adjustments to allocation variables if necessary, to reflect potential disproportionate effects of longer shipping distance on rural, disadvantaged patients.

Sharon Bartosh | 09/02/2021

Continuous distribution will replace the current classification-based allocation system with a points- based allocation system. A points-based framework assigns a composite allocation score to each candidate and that score will determine the order that organs are offered. The candidate’s CAS will consider a combination of donor and candidate characteristics including medical urgency, post- transplant survival, candidate biology, patient access, and placement efficiency. This movement to a continuous distribution framework is meant to provide a more equitable approach to matching candidates and donors and to remove hard boundaries that prevent candidates from being prioritized higher on the match run. This concept paper outlines proposed attributes for the CAS and asks for feedback from the transplant community regarding additional attributes that should be included, as well as weighting of attributes in final CAS score and best ways to convert the current system into points- based framework. It is unclear from the proposal how children will be handled within this system and whether they too will be allocated organs on the basis of their CAS. If they are also going to be given a CAS, it is my assumption that they will receive the same weighting for things such as blood type, sensitization, proximity and waiting time. The larger question is related to weight of age. Issues and concerns to consider from a pediatric standpoint are; 1. Weighting of age. Questions needing to be answered are; Should children be placed into the model on a continuous distribution of their age (younger with more priority and the oldest approaching adult priority) or should they be grouped into a few categories (for example; 1-6 yr olds getting xxx points, 7-12 yr olds getting xx points, 13-18 yr olds getting x point). The basis for this differential in points would be related to the adverse effects of ESRD on growth and development being more substantial in the younger patients. 2. Another question we as a community should weigh in on is “should children on dialysis get more priority compared to those listed for a pre-emptive transplant?”. Currently there is no distinction but perhaps we should examine this question. I would tend to favor having children on dialysis prioritized over children not yet on dialysis. I am actually not sure how this is handled on the adult side and whether an adult listed pre-emptively is treated the same as someone who is on dialysis with regard to priority. I presume the number of adults listed pre-emptively is relatively low whereas in the peds side it is a much higher proportion. 3. How will the new system deal with the current policy that allows for children listed prior to their 18th birthday but not being transplanted by their 18th birthday to retain their “pediatric priority” until transplanted. I would be in favor of maintaining this priority within the CAS. This issue will come up with all the pediatric organs since this continued pediatric priority after turning 18 crosses all the organs. 4. The proposal does not give much detail as to how children will be allocated kidneys on the basis of KDPI. Currently children are prioritized for kidneys with a KDPI < 35 but this eliminates many kidneys from young donors from being offered to children. the problem with KDPI in general is that the determination of KDPI was used from data sets that looked at outcomes of adult and pediatric kidney donors transplanted only into adult recipients. Pediatric recipients were not included. Soooo, we don’t have data to help determine how these younger donors with KDPI > 35 fare in children and our community’s suspicion is relatively well in most cases. The fix to this issue is a complete redo of the KDPI using all donors into all recipients. Short of a complete redo of KDPI, the pediatric community would advocate for continued priority for children of kidneys with a KDPI < 35 AND a version of age matching with increased weighting going to pediatric donors with KDPI > 35 being offered to children. This would allow the transplant hospital to look at the offer from the peds donor and on an individual basis decide if the “match” was reasonable for the child. 5. Any agreed upon CAS needs to be modeled thoroughly to determine how children will fare within a new continuous distribution allocation framework prior to implementation. 6. Will multiorgan allocation remain a hard boundary for children? The new proposed system does not address (as far as I can tell) the current prioritization of multiorgan candidates above pediatric candidates, sensitized candidates and prior living donor candidates. With the continuously increasing numbers of multiorgan candidates (see table in attachment) and the previously stagnant peds transplant volume (the new allocation system is resulting in more children being transplanted) this, in the opinion of the peds kidney transplant community, continues to be an allocation policy that needs to be addressed.

Attachment

Region 5 | 08/30/2021

A member commented that in order for continuous distribution to achieve equity the weighting of each variable will be important - an overweighting of longer distance compared to medical urgency will result in points given to more local patients than those most in need, which would be a step backwards. The member cautioned that the OPTN and committees should be extremely careful not to overweigh physical proximity of donor and recipient or to give too high a coefficient for distance in the overall score, especially for organs that can travel. A member expressed mixed feelings about the use of EPTS, since traditionally wait time has been given a very heavy preponderance for kidney allocation. A member suggested that in order to stratify candidates for medical urgency there needs to be a better predictive tool that can help educate members on the criteria and risk factors for death on the waitlist or progression of CAD or vacular disease that may preclude transplant or result in removal from the waitlist. EPTS is probably too blunt an instrument to predict post-transplant outcomes in order to prioritize and order candidates for transplants. But the member pointed out that EPTS may still be useful for donor/recipient matching. Several members support a non-linear distance formula since cold ischemic times do not correlate linearly with distance from organ donor to recipient location. Another member commented that the driving forces is what is best for the patients and pointed out that there is a cost to fairness and equity. A member expressed the need for a uniform system to do a virtual cross-match but that may be a topic for the Histocompatibility Committee. A member asked for more data on how kidney and pancreas donation effects the pediatric population. A member suggested that movement of the donor from their hospital of origin to a donor center can change placement efficiency and should be considered. The member believes that if there is commitment from the OPOs to have timely transport arranged, this could be minimized. Likewise, travel distance for tissues for physical crossmatches may be important. The member believes the continuous distribution scale should reflect components they have already agreed on as a community as being important: waitlist time, priority to high CPRA, proper pairing of low KDPI donors with those who will benefit the most, and distance from donor hospital to recipient center. This could be improved by a more continuous, fluid scale rather than the sharply defined cutoffs that currently exist, but should continue to reflect and prioritize those already debated topics. A member suggests that it will be very important to be consistent across KDPI categories for pediatric access - the lack of any pediatric priority for KDPI>35% prevents appropriate, efficient matching of small donors (pediatric donors) with small recipients (children) - it is not clear how this impacts discard rate but would be extremely helpful to evaluate SRTR data in more detail as part of this process to consider. Also important a member suggests considering that EPTS is not currently applied for pediatric candidates – there is a need to either introduce consistency of using EPTS for all recipients, or factor this into the pediatric priority points. In the lung continuous distribution proposal, the proposal assigns a standard number of "post-transplant survival" priority points to pediatric recipients because they were previously classified by Status and did not have scores calculated. To ensure system adaptability going forward, though, it may be preferable to have a calculate-able score that will apply to children as well instead of assigning a fixed post-transplant score that will not change despite trends in the overall score distribution.

Region 4 | 08/27/2021

Many attendees had feedback for the committee and provided the following comments: The committee needs to be careful about how they prioritize pancreas and kidney/pancreas candidates because very sick pancreas patients often do not benefit from a pancreas transplant. The committee should use different terminology rather than “sickest” for these patients. The plan to prioritize pancreata or combined pancreas/kidney transplant to the "sickest" patients seems counterintuitive in that neither transplant is life saving and it would seem more prudent to give less priority to these patients when they get sick with the exception of patients who are running out of dialysis access. The committee should proceed carefully with prioritization of patients and have a goal of maximizing the benefit of the donor organs. Committee will need to make sure that when prioritizing the “sickest” patients, that these types of patients are very well defined. It would be difficult to adjust kidney allocation for disease severity. Continuous distribution is a worthy goal, but must not be accomplished at the cost of utility and being good stewards of donor gifts. Pediatric priority and the geographic discrepancies in pediatric access to transplant needs to be carefully considered. Patient education will be needed. This is interesting work but we need to make sure it doesn’t get too complicated for patients. Having a complicated allocation system that is hard to understand could disenfranchise certain populations. It’s extremely important for patient education especially as allocation changes to medical factors and not wait time. Kidney allocation goes currently according to ETPS - which favors patients with better survival. Prioritizing sick patients (which might have higher ETPS) could collide with the ETPS based allocation.

Jason Rolls | 08/17/2021

Today's Regional Meeting featured a presentation by the KP Committee which described the evolving development of a widely continuous organ distribution model. Included were elements being considered in the determination of recipient priority for organ allocation in an evolved system. One of the elements mentioned concerned expected recipient post-transplant survival. In service of ethics and efficiency, I would ask the KP Committee to prioritize appropriate KDPI/EPTS matching in the evolving allocation system over a simple de-prioritization of patients with higher EPTS scores. If an older/higher KDPI donor is offered, perhaps additional consideration should be given to higher EPTS potential recipients on that match run to maximize organ and recipient survival parity, and thus efficient organ usage. If higher EPTS patients are de-prioritized regardless of the nature of the donor organ being offered, it will medically disenfranchise a large number of the patients we serve.

Anonymous | 08/13/2021

What is expected to be the overall national outcomes impact with these priorities? How are psychosocial/financial factors accounted for in the prediction models for longer term outcomes? We know those are both key factors in long term graft and patient survival. It also seems that with points for ease of distribution, this proposal advantages the wealthy and punishes the poor because the wealthy can multi-list in several areas to increase their accessibility. Lastly, and perhaps the most important, this is extremely complicated to understand because of so many factors. Being able to explain it to patients so they understand is critical. Transparency in organ distribution is imperative.