KAS Turns Four: The State of Deceased Donor Kidney Allocation in the U.S.

Stewart, Darren; Wilk, Amber R.; Klassen, David K.

doi:10.21926/obm.transplant.1901041

Cited by 12 publications

(20 citation statements)

References 34 publications

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“…Early post-KAS analyses revealed trends regarding transplant rates across CPRA groups, but extrapolating these trends into the future proved challenging given the bolus effects seen immediately post-implementation. Analyses at the first, second, third, and fourth years post-KAS provided clarity regarding the types of patients who had benefited from the changes introduced and indicated that the system had stabilized over time [5,6,[10][11][12][13]. Ostensibly fueled by the overall rise in donors, TRs steadily increased under KAS for all groups with one notable exception, the highly sensitized group (CPRA 99.9%+), whose TR remained less than half that of the average candidate.…”

Section: Discussionmentioning

confidence: 98%

“…The changes made by KAS have made remarkable strides in providing equity in access to transplants while also balancing utility. Recently implemented amendments to KAS that replaced the Donor Service Area distribution with 250 nautical mile circles may further increase transplant rates for those who are harder to match with due to biological reasons and those who are predicted to have high re-transplant rates, among other factors [12,13,15,16]. The clarity in acceptable anti-A2 titers may also increase transplantation among the ABO-incompatible recipients.…”

Section: Fundingmentioning

confidence: 99%

See 1 more Smart Citation

Beyond CPRA: Identifying Sensitized Kidney Candidates with Markedly Low Access to Deceased Donor Transplantation by Granular CPRA and Blood Type

Maldonado¹,

Sjöholm²,

Lee³

et al. 2021

obm transplant

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Prioritization in the US Kidney Allocation System (KAS) has led to an improvement in the rates of transplantation in highly sensitized (HS) patients. However, there is a subset of HS patients who are at a disadvantage, despite prioritization under KAS. The purpose of this study was to describe the transplant rate (TR) by calculated panel reactive antibody (CPRA) of HS candidates before and five years post-KAS to characterize their access to deceased donor transplants and quantify the number of HS candidates who are at a marked disadvantage in accessing kidneys. Using de-identified OPTN data, the number of solitary deceased donor kidney transplants performed (by month) from June 2013 through December 2019 was analyzed for four CPRA groups (95–97%, 98%, 99%, and 100%), with the CPRA 100% group further stratified into two subgroups (99.5–99.9% and >99.9%). The impact of the recipient blood group was assessed as an additional factor in TR. Immediately after KAS, TR rose 7-fold from 0.26% to 1.7% for the CPRA 99–100% group as a whole, and 12-fold and 8-fold for the CPRA 99.5–99.9% and CPRA 99.9%+ groups, respectively. However, the post-KAS mean TR of 0.63% for CPRA 99.9%+ candidates remained markedly lower than the mean TR of the other sensitized groups: 1.5% for CPRA 95–97%, 1.4% for CPRA 98%, 2.0% for CPRA 99%, and 3.5% for CPRA 99.5–99.9%; a statistically significant 6-fold advantage of the CPRA 99.5–99.9% group over CPRA 99.9%+ candidates was observed, despite both groups receiving national priority under KAS. Patients with a CPRA of 99.9%+ and blood group B were 2.16, 1.98, and 1.75 times less likely to receive a transplant compared to the same CPRA group with blood groups A, AB, and O, respectively, despite changes to KAS allocating blood type A2 and A2B to recipients with blood group B. Although the TR increased sharply for the CPRA 99.9%+ group with KAS, it remained markedly lower than the average despite national priority.

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Section: Discussionmentioning

confidence: 98%

Section: Fundingmentioning

confidence: 99%

Beyond CPRA: Identifying Sensitized Kidney Candidates with Markedly Low Access to Deceased Donor Transplantation by Granular CPRA and Blood Type

Maldonado¹,

Sjöholm²,

Lee³

et al. 2021

obm transplant

View full text Add to dashboard Cite

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“…For those with CPRA values above 99.9%, benefit has been less evident, with the overwhelming majority of candidates either dead, delisted or still waiting after 3 years compared to those transplanted 3 . Despite a short‐lived “bolus” effect after the implementation of the current KAS, patients with a CPRA > 99.9% continue to have transplant rates far below other highly sensitized patients 14‐17 . In this analysis, 13 XM+ imlifidase‐treated patients with CPRA ≥ 99.9% were considered those with the highest unmet medical need, unlikely to be transplanted, and despite these immunologic challenges, demonstrated outcomes comparable to the overall group.…”

Section: Discussionmentioning

confidence: 99%

Outcomes at 3 years posttransplant in imlifidase-desensitized kidney transplant patients

Kjellman

Maldonado

Sjöholm

et al. 2021

American Journal of Transplantation

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Imlifidase is a cysteine proteinase which specifically cleaves IgG, inhibiting Fc‐mediated effector function within hours of administration. Imlifidase converts a positive crossmatch to a potential donor (T cell, B cell, or both), to negative, enabling transplantation to occur between previously HLA incompatible donor‐recipient pairs. To date, 39 crossmatch positive patients received imlifidase prior to a kidney transplant in four single‐arm, open‐label, phase 2 studies. At 3 years, for patients who were AMR+ compared to AMR−, death‐censored allograft survival was 93% vs 77%, patient survival was 85% vs 94%, and mean eGFR was 49 ml/min/1.73 m2 vs 61 ml/min/1.73 m2, respectively. The incidence of AMR was 38% with most episodes occurring within the first month post‐transplantation. Sub‐analysis of patients deemed highly sensitized with cPRA ≥ 99.9%, and unlikely to be transplanted who received crossmatch‐positive, deceased donor transplants had similar rates of patient survival, graft survival, and eGFR but a higher rate of AMR. These data demonstrate that outcomes and safety up to 3 years in recipients of imlifidase‐enabled allografts is comparable to outcomes in other highly sensitized patients undergoing HLA‐incompatible transplantation. Thus, imlifidase is a potent option to facilitate transplantation among patients who have a significant immunologic barrier to successful kidney transplantation. Clinical Trial: ClinicalTrials.gov (NCT02790437), EudraCT Number: 2016‐002064‐13.

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“…Unlike previous studies examining deceased donor kidney discards, we chose to keep our study at the donor level (as opposed to the kidney level) and did not exclude kidneys transplanted to specific groups such as high Calculated Panel Reactive Antibodies or multiorgan candidates or en bloc transplants. Recent evidence suggests that approximately 10% of all kidney transplants occur within the high Calculated Panel Reactive Antibodies population . Limiting the study population to standard allocation policy may overestimate our ability to identify deceased donor kidneys at risk of being placed.…”

Section: Methodsmentioning

confidence: 99%

“…Recent evidence suggests that approximately 10% of all kidney transplants occur within the high Calculated Panel Reactive Antibodies population. 19 Limiting the study population to standard allocation policy may overestimate our ability to identify deceased donor kidneys at risk of being placed. Our rationale for a donor level analysis was that key variables found in previous studies, such as biopsy results and pump parameters, are typically not available at the time of match.…”

Section: Definition Of Cohort and Outcomementioning

confidence: 99%

Can donor narratives yield insights? A natural language processing proof of concept to facilitate kidney allocation

Placona

Martinez

McGehee

et al. 2020

American Journal of Transplantation

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Although expedited placement could ameliorate stagnant kidney utilization, precisely identifying difficult‐to‐place organs is crucial to mitigate potential harms associated with this policy. Existing algorithms have only leveraged structured data from the Organ Procurement and Transplantation Network (OPTN); however, detailed, free text case information about a donor exists. No known research exists about the utility of these data. We developed a model to predict the probability of delay or discard for adult deceased kidney donors between 2010 and 2018, leveraging donor free text data. The resultant model had a c‐statistic of 0.75 compared to 0.80 ( Reduced Probability of Delay or Discard [model], r‐PODD) and 0.77 ( Kidney Donor Profile Index, KDPI) on the test dataset. Analysis of the top predictive words suggest both known and potentially novel clinical factors (ie, a known factor such as hypertension vs a novel factor such as stents), and nuanced social factors (intravenous drug use) could negatively affect kidney utilization. These findings suggest that donor narratives have utility; the natural language processing (NLP) model is only moderately correlated with existing indices and provides directional evidence about additional cardiovascular risk factors that may affect kidney utilization. More research is needed to understand the potential to enhance existing indices of kidney utilization to better enable and mitigate the effects of policy interventions such as expedited placement.

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KAS Turns Four: The State of Deceased Donor Kidney Allocation in the U.S.

Cited by 12 publications

References 34 publications

Beyond CPRA: Identifying Sensitized Kidney Candidates with Markedly Low Access to Deceased Donor Transplantation by Granular CPRA and Blood Type

Beyond CPRA: Identifying Sensitized Kidney Candidates with Markedly Low Access to Deceased Donor Transplantation by Granular CPRA and Blood Type

Outcomes at 3 years posttransplant in imlifidase-desensitized kidney transplant patients

Can donor narratives yield insights? A natural language processing proof of concept to facilitate kidney allocation

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