Changes in Discard Rate After the Introduction of the Kidney Donor Profile Index (KDPI)

Preoperative Risk Assessment of Early Kidney Graft Loss

Background

A large proportion of potential organ donors are not utilized for kidney transplantation out of risk of early allograft loss because of donor-related characteristics. These can be summarized using kidney donor profile index (KDPI). Because KDPI affects the choice of the recipient, the predictive ability of KDPI is tied to recipient attributes. These have been questioned to explain most of the predictive ability of KDPI. This study aims to quantify the effect of the donor on early graft loss (EGL) by accounting for nonrandom allocation.

Methods

This study included patients undergoing kidney transplantation from deceased donors between 2014 and 2020 from the Scientific Registry of Transplantation Recipients. EGL, defined as a return to dialysis or retransplantation during the first posttransplant year, was the primary endpoint. Nonrandom allocation and donor-recipient matching by KDPI necessitated the use of inverse probability treatment weighting, which served to assess the effect of KDPI and mitigate selection bias in a weighted Cox regression model.

Results

The study comprised 89 290 transplantations in 88 720 individual patients. Inverse probability treatment weighting resulted in a good balance of recipient covariates across values of continuous KDPI. Weighted analysis showed KDPI to be a significant predictor for short-term outcomes. A comparable (in terms of age, time on dialysis, previous transplants, gender, diabetes status, computed panel-reactive antibodies, and HLA mismatches) average recipient, receiving a kidney from a donor with KDPI 40-60 had a 3.5% risk of EGL increased to a risk of 7.5% if received a kidney from a KDPI >95 donor (hazard ratio, 2.3; 95% confidence interval, 1.9-2.7). However, for all-cause survival KDPI was less influential.

Conclusions

The predictive ability of KDPI does not stem from recipient confounding alone. In this large sample-sized study, modeling methods accounting for nonindependence of recipient selection verify graft quality to effectively predict short-term transplantation outcomes.

A Transplant-Inclusive Value-Based Kidney Care Payment Model

In the United States, kidney care payment models are migrating toward value-based care (VBC) models incentivizing quality of care at lower cost. Current kidney VBC models will continue through 2026. We propose a future transplant-inclusive VBC (TIVBC) model designed to supplement current models focusing on patients with advanced chronic kidney disease (CKD) and end-stage kidney disease (ESKD). The proposed TIVBC is structured as an episode-of-care model with risk-based reimbursement for "referral/evaluation/waitlisting" (REW, referencing kidney transplantation), "primary hospitalization to 180 days posttransplant," and "long-term graft survival." Challenges around organ acquisition costs, adjustments to quality metrics, and potential criticisms of the proposed model are discussed. We propose next steps in risk-adjustment and cost-prediction to develop as an end-to-end, TIVBC model.

Organ Nonutilization Following Revision to the Public Health Service Donor Risk Criteria for HIV, HCV, or HBV Transmission

BACKGROUND

Organs from Public Health Service criteria (PHSC) donors, previously referred to as PHS infectious-risk donors, have historically been recovered but not used, traditionally referred to as "discard," at higher rates despite negligible risk to recipients. On March 1, 2021, the definition of PHSC donors narrowed to include only the subset of donors deemed to have meaningfully elevated risk in the current era of improved infectious disease testing.

METHODS

Using Scientific Registry of Transplant Recipients data from May 1, 2019, to December 31, 2022, we compared rates of PHSC classification and nonutilization of PHSC organs before versus after the March 1, 2021, policy change among recovered decedents using the χ 2 tests. We performed an adjusted interrupted time series analysis to examine kidney and liver recovery/nonuse (traditionally termed "discard") and kidney, liver, lung, and heart nonutilization (nonrecovery or recovery/nonuse) prepolicy versus postpolicy.

RESULTS

PHSC classification dropped sharply from 24.5% prepolicy to 15.4% postpolicy ( P  < 0.001). Before the policy change, PHSC kidney recovery/nonuse, liver nonuse, lung nonuse, and heart nonuse were comparable to non-PHSC estimates (adjusted odds ratio: kidney =  0.98 1.06 1.14 , P  = 0.14; liver =  0.85 0.92 1.01 , P  = 0.07; lung =  0.91 0.99 1.08 , P  = 0.83; heart =  0.89 0.97 1.05 , P  = 0.47); following the policy change, PHSC kidney recovery/nonuse, liver nonuse, lung nonuse, and heart nonuse were lower than non-PHSC estimates (adjusted odds ratio: kidney =  0.77 0.84 0.91 , P  < 0.001; liver =  0.77 0.84 0.92 , P  < 0.001; lung =  0.74 0.81 0.90 , P  < 0.001; heart =  0.61 0.67 0.73 , P  < 0.001).

CONCLUSIONS

Even though PHSC donors under the new definition are a narrower and theoretically riskier subpopulation than under the previous classification, PHSC status appears to be associated with a reduced risk of kidney and liver recovery/nonuse and nonutilization of all organs. Although historically PHSC organs have been underused, our findings demonstrate a notable shift toward increased PHSC organ utilization.

Expanding Access to High KDPI Kidney Transplant for Recipients Aged 60 y and Older: Cost Utility and Survival

Background

Modern organ allocation systems are tasked with equitably maximizing the utility of transplanted organs. Increasing the use of deceased donor organs at risk of discard may be a cost-effective strategy to improve overall transplant benefit. We determined the survival implications and cost utility of increasing the use of marginal kidneys in an older adult Canadian population of patients with end-stage kidney disease.

Methods

We constructed a cost-utility model with microsimulation from the perspective of the Canadian single-payer health system for incident transplant waitlisted patients aged 60 y and older. A kidney donor profile index score of ≥86 was considered a marginal kidney. Donor- and recipient-level characteristics encompassed in the kidney donor profile index and estimated posttransplant survival scores were used to derive survival posttransplant. Patients were followed up for 10 y from the date of waitlist initiation. Our analysis compared the routine use of marginal kidneys (marginal kidney scenario) with the current practice of limited use (status quo scenario).

Results

The 10-y mean cost and quality-adjusted life-years per patient in the marginal kidney scenario were estimated at $379 485.33 (SD: $156 872.49) and 4.77 (SD: 1.87). In the status quo scenario, the mean cost and quality-adjusted life-years per patient were $402 937.68 (SD: $168 508.85) and 4.37 (SD: 1.87); thus, the intervention was considered dominant. At 10 y, 62.8% and 57.0% of the respective cohorts in the marginal kidney and status quo scenarios remained alive.

Conclusions

Increasing the use of marginal kidneys in patients with end-stage kidney disease aged 60 y and older may offer cost savings, improved quality of life, and greater patient survival in comparison with usual care.

Interaction between cold ischemia time and Kidney Donor Profile Index on postrenal transplant outcomes

We analyzed whether there is an interaction between the Kidney Donor Profile Index (KDPI) and cold ischemia time (CIT) in recipients of deceased donor kidney transplant (KTs). Adults who underwent KTs in the United States between 2014 and 2020 were included and divided into 3 KDPI groups (≤20%, 21%-85%, >85%) and 4 CIT strata (<12, 12-17.9, 18-23.9, ≥24 hours). Multivariate analyses were used to test the interaction between KDPI and CIT for the following outcomes: primary graft nonfunction (PGNF), delayed graft function (DGF), estimated glomerular filtration rate (eGFR) at 6 and 12 months, patient survival, graft survival, and death-censored graft survival (DCGS). A total of 69,490 recipients were analyzed: 18,241 (26.3%) received a graft with KDPI ≤20%, 46,953 (67.6%) with KDPI 21%-85%, and 4,296 (6.2%) with KDPI >85%. Increasing KDPI and CIT were associated with worse post-KT outcomes. Contrary to our hypothesis, howerver, the interaction between KDPI and CIT was statistically significant only for PGNF and DGF and eGFR at 6 months. Paradoxically, the negative coefficient of the interaction suggested that increasing duration of CIT was more detrimental for low and intermediate-KDPI organs relative to high-KDPI grafts. Conversely, for mortality, graft survival, and DCGS, we found that the interaction between CIT and KDPI was not statistically significant. We conclude that, high KDPI and prolonged CIT are independent risk factors for inferior outcomes after KT. Their interaction, however, is statistically significant only for the short-term outcomes and more pronounced on low and intermediate-KDPI grafts than high-KDPI kidneys.

The Kidney Not Taken: Single-Kidney Use in Deceased Donors

BACKGROUND

The nonuse rate for kidneys recovered from deceased donors is increasing, rising to 27% in 2023. In 10% of these cases, 1 kidney is transplanted but the mate kidney is not.

STUDY DESIGN

We conducted a retrospective, single-center cohort study from December 2001 to May 2023 comparing single kidneys transplanted at our center (where the contralateral kidney was not used) to kidneys where both were transplanted separately, at least 1 of which was at our center.

RESULTS

We performed 395 single deceased-donor kidney transplants in which the mate kidney was not transplanted. Primary reasons for mate kidney nonuse were as follows: no recipient located or list exhausted (33.4%), kidney trauma or injury or anatomic abnormalities (18.7%), biopsy findings (16.7%), and poor renal function (13.7%). Mean donor and recipient ages were 51.5 ± 14.2 and 60 ± 12.6 years, respectively. Mean kidney donor profile index was 73% ± 22%, and 104 donors (26.3%) had kidney donor profile index >85%. Mean cold ischemia was 25.6 ± 7.4 hours, and 280 kidneys (70.7%) were imported. Compared with 2,303 concurrent control transplants performed at our center, primary nonfunction or thrombosis (5.1% single vs 2.8% control) and delayed graft function (35.4% single vs 30.1% control) were greater with single-kidney use (both p < 0.05). Median patient and death-censored graft survival were shorter in the single group (11.6 vs 13.5 years, p = 0.03 and 11.6 vs 19 years, p = 0.003), although the former was at least double median survival on the waiting list. In patients with functioning grafts in the single-kidney group, 1-year mean serum creatinine was 1.77 ± 0.8 mg/dL and estimated glomerular filtration rate was 44.8 ± 20 mL/min/1.73 m 2 .

CONCLUSIONS

These findings suggest that many mate kidneys are being inappropriately rejected, given the acceptable outcomes that can be achieved by transplanting the single kidney in appropriately selected recipients.

Prognostic Models in Nephrology: Where Do We Stand and Where Do We Go from Here? Mapping Out the Evidence in a Scoping Review

Prognostic models can strongly support individualized care provision and well-informed shared decision making. There has been an upsurge of prognostic research in the field of nephrology, but the uptake of prognostic models in clinical practice remains limited. Therefore, we map out the research field of prognostic models for kidney patients and provide directions on how to proceed from here. We performed a scoping review of studies developing, validating, or updating a prognostic model for patients with CKD. We searched all published models in PubMed and Embase and report predicted outcomes, methodological quality, and validation and/or updating efforts. We found 602 studies, of which 30.1% concerned CKD populations, 31.6% dialysis populations, and 38.4% kidney transplantation populations. The most frequently predicted outcomes were mortality ( n =129), kidney disease progression ( n =75), and kidney graft survival ( n =54). Most studies provided discrimination measures (80.4%), but much less showed calibration results (43.4%). Of the 415 development studies, 28.0% did not perform any validation and 57.6% performed only internal validation. Moreover, only 111 models (26.7%) were externally validated either in the development study itself or in an independent external validation study. Finally, in 45.8% of development studies no useable version of the model was reported. To conclude, many prognostic models have been developed for patients with CKD, mainly for outcomes related to kidney disease progression and patient/graft survival. To bridge the gap between prediction research and kidney patient care, patient-reported outcomes, methodological rigor, complete reporting of prognostic models, external validation, updating, and impact assessment urgently need more attention.

Validation of the kidney donor profile index (KDPI) for deceased donor kidney transplants in China

BACKGROUND

The kidney donor profile index (KDPI) evaluates kidney donor's age, height, weight, ethnicity, cause of death, high blood pressure, diabetes, exposure to hepatitis C and estimated glomerular filtration (eGFR). Kidneys with lower KDPI scores are expected to function longer that those with higher KPDI values. The applicability of KDPI score in Chinese kidney transplant donation has not yet been validated. This study evaluated the prognostic value of KDPI score in Chinese kidney transplant patients.

METHODS

A retrospective analysis was conducted on 184 deceased donors and 353 corresponding kidney transplant patients at the Organ Transplantation Department of Renmin Hospital of Wuhan University between 2018 and 2021. The donors and recipients were stratified into four groups based on their KDPI score: KDPI 85-100, KDPI 60-84, KDPI 21-59, and KDPI 0-20.

RESULTS

As expected, the KDPI 85-100 group was associated with a poor short-term renal function (both postoperative creatinine and eGFR with P > 0.05), a higher incidence of delayed graft function (DGF; 25.5% for KDPI 85-100 group vs. 10.2% for KDPI 60-84 group vs. 5.4% for KDPI 21-59 group vs. 0 for KDPI 0-20 group, all P > 0.05). Furthermore, the same groups showed worse 3-year patient survival rate: 86.3% for KDPI 85-100 group vs. 97.01% for KDPI 60-84 group vs. 97.83% for KDPI 21-59 group vs. 100% for KDPI 0-20 group, all P > 0.05); and renal survival rate: 82.6% for KDPI 85-100 group vs. 92.99% KDPI 60-84 group vs.97.83% for KDPI 21-59 group vs. 100% for KDPI 0-20 group, all P > 0.05). Our analysis showed that the KDPI score had a good predictive value for the survival of kidney transplants and patients in our center (area under the curve: 0.728 and 0.76, P > 0.05).

CONCLUSION

We recommend that the KDPI scoring system can be employed as an effective tool to predict kidney transplantation outcomes in deceased donation in China.

Single center experience and literature review of kidney transplantation from non-ideal donors with acute kidney injury: Risk and reward

INTRODUCTION

There is limited experience transplanting kidneys from either expanded criteria donors (ECD) or donation after circulatory death (DCD) deceased donors with terminal acute kidney injury (AKI).

METHODS

AKI kidneys were defined by a donor terminal serum creatinine level >2.0 mg/dL whereas non-ideal deceased donor (NIDD) kidneys were defined as AKI/DCD or AKI/ECDs.

RESULTS

From February 2007 to March 2023, we transplanted 266 single AKI donor kidneys including 29 from ECDs, 29 from DCDs (n = 58 NIDDs), and 208 from brain-dead standard criteria donors (SCDs). Mean donor age (43.7 NIDD vs. 33.5 years SCD), KDPI (66% NIDD vs. 45% SCD), and recipient age (57 NIDD vs. 51 years SCD) were higher in the NIDD group (all p < .01). Mean waiting times (17.8 NIDD vs. 24.2 months SCD) and dialysis duration (34 NIDD vs. 47 months SCD) were shorter in the NIDD group (p < .05). Delayed graft function (DGF, 48%) and 1-year graft survival (92.7% NIDD vs. 95.9% SCD) was similar in both groups. Five-year patient and kidney graft survival rates were 82.1% versus 89.9% and 82.1% versus 75.2% (both p = NS) in the NIDD versus SCD groups, respectively.

CONCLUSIONS

The use of kidneys from AKI donors can be safely liberalized to include selected ECD and DCD donors.

Contrast-enhanced ultrasonography-based renal blood perfusion in brain-dead donors predicts early graft function

PURPOSE

The aim of this study was to quantify renal microcirculatory perfusion in braindead donors using contrast-enhanced ultrasonography (CEUS), and to establish an accurate, noninvasive, and convenient index for predicting delayed graft function (DGF) post-transplantation.

METHODS

In total, 90 brain-dead donor kidneys (training group, n=60; validation group, n=30) examined between August 2020 and November 2022 were recruited in this prospective study. CEUS was performed on the kidneys of brain-dead donors 24 hours before organ procurement and time-intensity curves were constructed. The main measures were arrival time, time to peak, and peak intensity of the kidney segmental arteries, cortex, and medulla. Recipients were divided into DGF and non-DGF groups according to early post-transplant graft function. The area under the receiver operating characteristic curve (AUC) was used to assess diagnostic performance.

RESULTS

The arrival time of the kidney segmental artery and cortex and the time interval between the time to peak of the segmental artery and cortex were identified as independent factors associated with DGF by multivariate stepwise regression analysis. A new index for the joint prediction model of three variables, the contrast-enhanced ultrasonography/Kidney Donor Profile index (CEUS-KDPI), was developed. CEUS-KDPI showed high accuracy for predicting DGF (training group: AUC, 0.91; sensitivity, 90.5%; specificity, 92.3%; validation group: AUC, 0.84; sensitivity, 75.0%; specificity, 92.3%).

CONCLUSION

CEUS-KDPI accurately predicted DGF after kidney transplantation. CEUS may be a potential noninvasive tool for bedside examinations before organ procurement and may be used to predict early renal function after kidney transplants kidneys from donors after brain death.

Considerable Variability Among Transplant Nephrologists in Judging Deceased Donor Kidney Offers

Introduction

Transplant clinicians may disagree on whether or not to accept a deceased donor kidney offer. We investigated the interobserver variability between transplant nephrologists regarding organ acceptance and whether the use of a prediction model impacted their decisions.

Methods

We developed an observational online survey with 6 real-life cases of deceased donor kidneys offered to a waitlisted recipient. Per case, nephrologists were asked to estimate the risk of adverse outcome and whether they would accept the offer for this patient, or for a patient of their own choice, and how certain they felt. These questions were repeated after revealing the risk of adverse outcome, calculated by a validated prediction model.

Results

Sixty Dutch nephrologists completed the survey. The intraclass correlation coefficient of their estimated risk of adverse outcome was poor (0.20, 95% confidence interval [CI] 0.08-0.62). Interobserver agreement of the decision on whether or not to accept the kidney offer was also poor (Fleiss kappa 0.13, 95% CI 0.129-0.130). The acceptance rate before and after providing the outcome of the prediction model was significantly influenced in 2 of 6 cases. Acceptance rates varied considerably among transplant centers.

Conclusion

In this study, the estimated risk of adverse outcome and subsequent decision to accept a suboptimal donor kidney varied greatly among transplant nephrologists. The use of a prediction model could influence this decision and may enhance nephrologists' certainty about their decision.

Predicting Time to and Average Quality of Future Offers for Kidney Transplant Candidates Declining a Current Deceased Donor Kidney Offer: A Retrospective Cohort Study

Background

At the time a kidney offer is made by an organ donation organization (ODO), transplant physicians must inform candidates on the pros and cons of accepting or declining the offer. Although physicians have a general idea of expected wait time to kidney transplantation by blood group in their ODO, there are no tools that provide quantitative estimates based on the allocation score used and donor/candidate characteristics. This limits the shared decision-making process at the time of kidney offer as (1) the consequences of declining an offer in terms of wait-time prolongation cannot be provided and (2) the quality of the current offer cannot be compared with that of offers that could be made to the specific candidate in the future. This is especially relevant to older transplant candidates as many ODOs use some form of utility matching in their allocation score.

Objective

We aimed to develop a novel method to provide personalized estimates of wait time to next offer and quality of future offers for kidney transplant candidates if they refused a current deceased donor offer from an ODO.

Design

A retrospective cohort study.

Setting

Administrative data from Transplant Quebec.

Patients

All patients who were actively registered on the kidney transplant wait list at any point between March 29, 2012 and December 13, 2017.

Measurements

The time to next offer was defined as the number of days between the time of the current offer and the next offer if the current one were declined. The quality of the offers was measured with the 10-variable Kidney Donor Risk Index (KDRI) equation.

Methods

Candidate-specific kidney offer arrival was modeled with a marked Poisson process. To derive the lambda parameter for the marked Poisson process for each candidate, the arrival of donors was examined in the 2 years prior to the time of the current offer. The Transplant Quebec allocation score was calculated for each ABO-compatible offer with the characteristics that the candidate presented at the time of the current offer. Offers where the candidate's score was lower than the scores of actual recipients of the second kidneys transplanted were filtered out from the candidate-specific kidney offer arrival. The KDRIs of offers that remained were averaged to provide an estimate of the quality of future offers, to be compared with that of the current offer.

Results

During the study period, there were 848 unique donors and 1696 transplant candidates actively registered. The models provide the following information: average time to next offer, time to which there is a 95% probability of receiving a next offer, average KDRI of future offers. The C-index of the model was 0.72. When compared with providing average group estimates of wait time and KDRI of future offers, the model reduced the root-mean-square error in the predicted time to next offer from 137 to 84 days and that of predicted KDRI of future offers from 0.64 to 0.55. The precision of the model's predictions was higher when observed times to next offer were 5 months or less.

Limitations

The models assume that patients declining an offer remain wait-listed until the next one. The model only updates wait time every year after the time of an offer and not in a continuous fashion.

Conclusion

By providing personalized quantitative estimates of time to and quality of future offers, our new approach can inform the shared decision-making process between transplant candidates and physicians when a kidney offer from a deceased donor is made by an ODO.

Impacts of removing race from the calculation of the kidney donor profile index

The kidney donor risk index (KDRI), standardized as the kidney donor profile index (KDPI), estimates graft failure risk for organ allocation and includes a coefficient for the Black donor race that could create disparities. This study used the Scientific Registry of Transplant Recipients data to recalculate KDRI coefficients with and without the Black race variable for deceased donor kidney transplants from 1995 to 2005 (n = 69 244). The recalculated coefficients were applied to deceased kidney donors from 2015 to 2021 (n = 72 926) to calculate KDPI. Removing the Black race variable had a negligible impact on the model's predictive ability. When the Black race variable was removed, the proportion of Black donors above KDPI 85%, a category with a higher risk of organ nonuse, declined from 31.09% to 17.75%, closer to the 15.68% above KDPI 85% among non-Black donors. KDPI represents percentiles relative to all other donors, so the number of Black donors moving below KDPI 86% was roughly equal to the number of non-Black donors moving above KDPI 85%. Removing the Black donor indicator from KDRI/KDPI may improve equity without substantial overall impact on the transplantation system, though further improvement may require the use of absolute measures of donor risk KDRI rather than relative measures of risk KDPI.

An experiment on the impact of predictive analytics on kidney offer acceptance decisions

Due to the breadth of factors that might affect kidney transplant decisions to accept an organ or wait for another, presumably "better" offer, a high degree of heterogeneity in decision-making exists among transplant surgeons and hospitals. These decisions do not typically include objective predictions regarding the future availability of equivalent or better-quality organs, nor the likelihood of patient death while waiting for another organ. To investigate the impact of displaying such predictions on organ donation decision making, we conducted a statistically designed experiment involving 53 kidney transplant professionals, where kidney organ offers were presented via an online application and systematically altered to observe effects on decision making. We found that providing predictive analytics for time-to-better offer and patient mortality improves decision consensus and decision maker confidence in their decision. Providing a visual display of the patient's mortality slope under accept/reject conditions shortened the time to decide, but did not have an impact on the decision itself. Presenting risk of death in a loss frame as opposed to a gain frame improved decision consensus and decision confidence. Patient-specific predictions surrounding future organ offers and mortality may improve decision quality, confidence, and expediency while improving organ utilization and patient outcomes.

Long-term outcomes of kidney transplantation from deceased donors with terminal acute kidney injury: Single center experience and literature review

INTRODUCTION

Long-term outcomes of kidney transplantation from deceased donors (DDKTs) with terminal acute kidney injury (AKI) are not well defined.

METHODS

Single center retrospective review of DDKTs from 1/31/07-12/31/19. AKI kidneys were defined by a doubling of the donor's admission serum creatinine (SCr) level AND a terminal SCr ≥2.0 mg/dl.

RESULTS

A total of 188 AKI DDKTs were performed, including 154 from brain-dead standard criteria donors (SCD). Mean donor age was 36 years and mean Kidney Donor Profile Index was 50%; mean admission and terminal SCr levels were 1.3 and 3.1 mg/dl, respectively. With a mean follow-up of 94 months (median 89 months), overall patient (both 71.3%) and graft survival (54% AKI vs. 57% non-AKI) rates were comparable to concurrent DDKTs from brain-dead non-AKI SCDs (n = 769). Delayed graft function (DGF) was higher in AKI kidney recipients (47% vs. 20% non-AKI DDKTs, p < .0001). DGF was associated with lower graft survival in recipients of both AKI and non-AKI SCD kidneys but the impact was earlier and more pronounced in non-AKI recipients.

CONCLUSIONS

Despite having more than twice the incidence of DGF, kidneys from deceased donors with terminal AKI have long-term outcomes comparable to non-AKI SCD kidneys and represent a safe and effective method to expand the donor pool.

Kidney Transplantation Outcome Predictions (KTOP): A Risk Prediction Tool for Kidney Transplants from Brain-dead Deceased Donors Based on a Large European Cohort

BACKGROUND

European kidney donation shortages mandate efficient organ allocation by optimizing the prediction of success for individual recipients.

OBJECTIVE

To develop the first European online risk tool for kidney transplant outcomes on the basis of recipient-only and recipient plus donor characteristics.

DESIGN, SETTING, AND PARTICIPANTS

We used individual recipient and donor risk factors and three outcomes (death, death with functioning graft [DWFG], and graft loss) for 32 958 transplants within the Eurotransplant kidney allocation system and the Eurotransplant senior program between January 2006 and May 2018 in eight European countries to develop and validate a risk tool.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Cox proportional-hazards models were used to analyze the association of risk factors with overall patient mortality, and proportional subdistribution hazard regression models for their association with graft loss and DWFG. Prediction models were developed with recipient-only and recipient-donor risk factors. Sensitivity analyses based on time-specific area under the receiver operating characteristic curve (AUC) with leave-one-country-out validation were performed and calibration plots were generated.

RESULTS AND LIMITATIONS

The 10-yr cumulative incidence rate was 37% for mortality, 12% for DWFG, and 41% for graft loss. In recipient-donor models the leading risk factors for mortality were recipient diabetes (hazard ratio [HR] 10.73), retransplantation (HR 3.08 per transplant), and recipient age (HR 1.08). Effects were similar for DWFG. For graft loss, diabetes (subdistributional HR [SHR] 1.32), increased donor age (SHR 1.02), and prolonged cold ischemia time (SHR 1.02) had increased SHRs. All p values were <0.001.

CONCLUSIONS

Previously identified risk factors for outcomes following kidney transplants allow for outcome prediction with 10-yr AUC values of up to 0.81.

PATIENT SUMMARY

Using European data, we estimated individual risks to predict the success of kidney transplants and support physicians in decision-making. An online tool is now available (https://riskcalc.org/ktop/) for predicting kidney transplant outcomes both before and after a donor has been identified.

Deceased donor kidneys are discarded at higher rates when labeled as high kidney donor profile index

The kidney donor risk index (KDRI) and percentile conversion, kidney donor profile index (KDPI), provide a continuous measure of donor quality. Kidneys with a KDPI >85% (KDPI₈₅ ) are referred to as "high KDPI." The KDPI₈₅ cutoff changes every year, impacting which kidneys are labeled as KDPI_HIGH . We examine kidney utilization around the KDPI₈₅ cutoff and explore the "high KDPI" labeling effect. KDRI to KDPI Mapping Tables from 2012 to 2020 were used to determine the yearly KDRI₈₅ value. Organ Procurement and Transplantation Network data was used to calculate discard rates and model organ use. KDRI₈₅ varied between 1.768 and 1.888. In a multivariable analysis, kidney utilization was lower for KDPI 86% compared with KDPI 85% kidneys (p = .046). Kidneys with a KDRI between 1.785-1.849 were classified as KDPI_HIGH in the years 2015-2017 and KDPI_LOW in the years 2018-2020. The discard rate was 44.9% when labeled as KDPI_HIGH and 39.1% when labeled as KDPI_LOW (p < .01). For kidneys with the same KDRI, the high KDPI label is associated with increased discard. We should reconsider the appropriateness of the "high KDPI" label.

Kidney utilization in the Netherlands - do we optimally use our donor organs?

BACKGROUND

To ensure optimal utilization of deceased donor kidneys, it is important to understand the precise reasons why kidneys are discarded. In this study we aimed to obtain a comprehensive overview of kidney utilization and discard during the entire donation process in the Netherlands.

METHODS

In this retrospective cohort study we analysed kidney utilization of 3856 kidneys in the Netherlands between 1 January 2015 and 31 December 2020. For every kidney that was not transplanted, we determined the moment of and reason for discard through a unique case-by-case assessment.

RESULTS

Kidney discard according to the traditional definition (procured but not transplanted) was 7.8%. However, when kidneys that seemed medically suitable at the beginning of the donation process were also included, many more potential donor kidneys were lost and the total non-utilization was 24.4%. Subjectively presumed impaired organ quality was responsible for 34.2% of all discarded kidneys. Two-thirds of kidneys discarded due to acute kidney injury (AKI) had only AKI stage 1 or 2.

CONCLUSION

The classical definition of organ discard underestimates the non-utilization of deceased donor kidneys. Strategies to improve kidney utilization could be a revision of the maximum allowed agonal time in donation after circulatory death, careful consideration in reporting and accepting kidneys from donors with AKI and a prospectively filled registry of detailed organ discard reasons, including the 'silent' non-utilization before procurement.

Outcomes of de novo belatacept-based immunosuppression regimen and avoidance of calcineurin inhibitors in recipients of kidney allografts at higher risk for underutilization

To describe an experience using a protocol using de novo belatacept (DNB) based maintenance immunosuppression in the setting of lymphocyte depletion. A retrospective, observational study was performed on 37 kidney transplant recipients treated with the DNB protocol, which was defined as belatacept initiated within 7 days after a kidney transplant with steroids and mycophenolate with anti-thymocyte globulin (ATG) induction without concomitant calcineurin inhibitors (CNIs). Patients who received a deceased donor kidney meeting one or more of the following criteria: anticipated cold ischemia time (CIT) greater than 24 h, donation after cardiac death, donor acute kidney injury, and a Kidney Donor Profile Index (KDPI) >85% during the study period were included. Patient survival at 1 year was 97.3% and graft survival was 94.6%. Delayed graft function (DGF) occurred in 40.54% of the patients. Two patients experienced a Banff 1B acute cellular rejection. BK viremia was detected in 32.4% of patients. The mean estimated glomerular filtration rate (eGFR) calculated with the use of modification of diet in renal disease (MDRD) equation at 1 year in the study group was 54.7 ml/min/1.73 m² . We believe that utilization of the DNB protocol, which allows early CNI avoidance, may decrease organ discard rates.

Function and longevity of renal grafts from high-KDPI donors

BACKGROUND

High kidney-donor profile index (KDPI) kidneys have a shorter survival than grafts with lower KDPI values. It is still unclear, however, whether their shorter longevity depends on an inferior baseline function, faster functional decline, or the combination of both.

METHODS

We analyzed the estimated glomerular filtration rate (eGFR) of 605 consecutive recipients of deceased donor kidney transplants (KT) at 1, 3, 6, 12, 18, 24, 36, 48, and 60 months. Comparisons were performed among four groups based on KDPI quartile: Group I-KDPI ≤ 25% (n = 151), Group II-KDPI 26-50% (n = 182), Group III-KDPI 51-75% (n = 176), and Group IV-KDPI 〉 75% (n = 96). Linear mixed model analysis was subsequently used to assess whether KDPI was independently associated with the decline in eGFR during the first 5-years after KT. We also analyzed the incidence of delayed graft function (DGF), rejection within the first year after KT, patient survival, graft survival, and death censored graft survival based on KDPI group.

FINDINGS

High-KDPI grafts had lower eGFR immediately after KT, had a higher incidence of DGF and rejection. However, there were no signifcant differences in the adjusted rate (slope) of decline in eGFR among the four KDPI groups (P = .06). Although patient survival was signigicantly lower for recipients of high-KDPI grafts, death-censored graft survival was similar among the four KDPI groups (P = .33).

CONCLUSIONS

The shorter functional survival of high-KDPI grafts seems to be due to their lower baseline eGFR rather than a more rapid functional decline after KT.

Kidney Organ Allocation System: How to Be Fair

Transplantation is a life-saving medical intervention that unfortunately is constrained by scarcity of available organs. An ideal system for allocating organs should seek to achieve the greatest good for the greatest number of people. It also must be fair and not disadvantage certain populations. However, policies aimed at reducing disparities also must be balanced with considerations of utility (graft outcomes), cost, efficiency, and any adverse effects on organ utilization. Here, we discuss the ethical challenges of creating a fair and equitable organ allocation system, focusing on the principles governing deceased donor kidney transplant waitlists around the world. The kidney organ allocation systems in the United States, Australia, and Hong Kong are used as illustrations.

Hyperspectral Imaging (HSI) of Human Kidney Allografts

OBJECTIVE

Aim of our study was to test a noninvasive HSI technique as an intraoperative real time assessment tool for deceased donor kidney quality and function in human kidney allotransplantation.

SUMMARY OF BACKGROUND DATA

HSI is capable to deliver quantitative diagnostic information about tissue pathology, morphology, and composition, based on the spectral characteristics of the investigated tissue. Because tools for objective intraoperative graft viability and performance assessment are lacking, we applied this novel technique to human kidney transplantation.

METHODS

Hyperspectral images of distinct components of kidney allografts (parenchyma, ureter) were acquired 15 and 45 minutes after reperfusion and subsequently analyzed using specialized HSI acquisition software capable to compute oxygen saturation levels (StO2), near infrared perfusion indices (NIR), organ hemoglobin indices, and tissue water indices of explored tissues.

RESULTS

Seventeen kidney transplants were analyzed. Median recipient and donor age were 55 years. Cold ischemia time was 10.8 ± 4.1 hours and anastomosis time was 35 ± 7 minutes (mean ± standard deviation). Two patients (11.8%) developed delayed graft function (DGF). cold ischemia time was significantly longer (18.6 ± 1.6) in patients with DGF (P < 0.01). Kidneys with DGF furthermore displayed significant lower StO2 (P = 0.02) and NIR perfusion indices, 15 minutes after reperfusion (P < 0.01). Transplant ureters displayed a significant decrease of NIR perfusion with increased distance to the renal pelvis, identifying well and poor perfused segments.

CONCLUSION

Intraoperative HSI is feasible and meaningful to predict DGF in renal allografts. Furthermore, it can be utilized for image guided surgery, providing information about tissue oxygenation, perfusion, hemoglobin concentration, and water concentration, hence allowing intraoperative viability assessment of the kidney parenchyma and the ureter.

Kidney donor profile index and post-transplant health care utilization: Implications for value of transplant care delivery

BACKGROUND

Centers discard high kidney donor profile index (KDPI) allografts, potentially related to delayed graft function and prolonged hospital use by kidney transplant recipients (KTR). We sought to determine whether high KDPI KTRs have excess health care utilization.

METHODS

We conducted a retrospective cohort study from a high-volume center analyzing KTRs from January 3, 2011 to April 12, 2015 (n = 652). We measured differences in hospital use, emergency visits, and outpatient visits within the first 90 days between low (≤85%) versus high KDPI (>85%) KTRs, as well as long-term graft function and patient survival.

RESULTS

High (n = 107) and low KDPI (n = 545) KTRs had similar length of stay (median = 3 days, P = .66), and readmission rates at 7, 30, and 90 days after surgery (all, P > .05). High KDPI kidneys were not associated with excess utilization of the hospital, emergency services, outpatient transplant clinics, or ambulatory infusion visits on univariate or multivariate analysis (all, P > .05). Low KDPI KTRs had significantly better eGFR at 2 years (Low vs. High KDPI: 60.35 vs. 41.54 ml/min, P < .001), but similar 3-year patient and graft survival (both, P > .09).

CONCLUSIONS

High and low KDPI KTRs demonstrated similar 90-day risk-adjusted health care utilization, which should encourage use of high KDPI kidneys.

Nonutilization of Kidneys From Donors After Circulatory Determinant of Death

Background.

The expansion of donation after circulatory determination of death (DCDD) programs and unmet demands for kidney transplantation indicate that there is a need to improve the efficiency and utilization of these organs.

Methods.

We studied all DCDD donors retrieved for kidney transplantation in Australia between 2014 and 2019 and determined the factors associated with nonutilization using least absolute shrinkage and selection operator and random forest models. Self-organizing maps were used to group these donors into clusters with similar characteristics and features associated with nonutilization were defined.

Results.

Of the 762 DCDD donors, 116 (15%) were not utilized for kidney transplantation. Of the 9 clusters derived from self-organizing map, 2 had the highest proportions of nonutilized kidneys. Factors for nonutilization (adjusted odds ratio [95% confidence interval], per SD increase) were duration from withdrawal of cardiorespiratory support till death (1.38 [1.16-1.64]), admission and terminal serum creatinine (1.43 [1.13-1.85]) and (1.41 [1.16-1.73]). Donor kidney function and duration of warm ischemia were the main factors for clinical decisions taken not to use kidneys from DCDD donors.

Conclusions.

Donor terminal kidney function and the duration of warm ischemia are the key factors for nonutilization of DCDD kidneys. Strategies to reduce the duration of warm ischemia and improve post-transplant recipient kidney function may reduce rates of nonutilization.

The Independent Effects of Procurement Biopsy Findings on Ten-Year Outcomes of Extended Criteria Donor Kidney Transplants

Introduction

Methods

Results

Conclusion

The Kidney Donor Profile Index (KDPI) Correlates With Histopathologic Findings in Post-reperfusion Baseline Biopsies and Predicts Kidney Transplant Outcome

Background

The increasing organ shortage in kidney transplantation leads to the necessity to use kidneys previously considered unsuitable for transplantation. Numerous studies illustrate the need for a better decision guidance rather than only the classification into kidneys from standard or expanded criteria donors referred to as SCD/ECD-classification. The kidney donor profile index (KDPI) exhibits a score utilizing a much higher number of donor characteristics. Moreover, graft biopsies provide an opportunity to assess organ quality.

Methods

In a single center analysis 383 kidney transplantations (277 after deceased and 106 after living donation) performed between January 1st, 2006, and December 31st, 2016, retrospectively underwent SCD/ECD and KDPI scoring. Thereby, the quality of deceased donor kidneys was assessed by using the KDPI and the living donor kidneys by using the living KDPI, in the further analysis merged as (L)KDPI. Baseline biopsies taken 10 min after the onset of reperfusion were reviewed for chronic and acute lesions. Survival analyses were performed using Kaplan-Meier analysis and Cox proportional hazards analysis within a 5-year follow-up.

Results

The (L)KDPI correlated with glomerulosclerosis (r = 0.30, p < 0.001), arteriosclerosis (r = 0.33, p < 0.001), interstitial fibrosis, and tubular atrophy (r = 0.28, p < 0.001) as well as the extent of acute tubular injury (r = 0.20, p < 0.001). The C-statistic of the (L)KDPI concerning 5-year death censored graft survival was 0.692. Around 48% of ECD-kidneys were classified as (L)KDPI<85%. In a multivariate Cox proportional hazard analysis including (preformed) panel reactive antibodies, cold ischemia time, (L)KDPI, and SCD/ECD-classification, the (L)KDPI was significantly associated with risk of graft loss (hazard ratio per 10% increase in (L)KDPI: 1.185, 95% confidence interval: 1.033–1.360, p = 0.025). Survival analysis revealed decreased death censored (p < 0.001) and non-death censored (p < 0.001) graft survival in kidneys with an increasing (L)KDPI divided into groups of <35, 35–85, and >85%, respectively.

Conclusion

With a higher granularity compared to the SCD/ECD-classification the (L)KDPI is a promising tool to judge graft quality. The correlation with chronic and acute histological lesions in post-reperfusion kidney biopsies underlines the descriptive value of the (L)KDPI. However, its prognostic value is limited and underlines the urgent need for a more precise prognostic tool adopted to European kidney transplant conditions.

Beyond Graft Survivl: A National Cohort Study Quantifying the Impact of Increasing Kidney Donor Profile Index on Recipient Outcomes 1 Year Post-transplantation

Background.

The reporting of a locally validated kidney donor profile index (KDPI) began in Australia in 2016. Across diverse populations, KDPI has demonstrated utility in predicting allograft survival and function. A metric that incorporates both elements may provide a more comprehensive picture of suboptimal recipient outcomes.

Methods.

A retrospective cohort study of adult kidney transplant recipients in Australia (January 2009 to December 2014) was conducted. Conventional recipient outcomes and a composite measure of suboptimal outcome (1-y allograft failure or estimated glomerular filtration rate [eGFR] <30 mL/min) were evaluated across KDPI intervals (KDPI quintiles and 5-point increments in the KDPI 81–100 cohort). The impact of increasing KDPI on allograft function (1-y eGFR) and a suboptimal outcome was explored using multivariable regression models, adjusting for potential confounding factors.

Results.

In 2923 donor kidneys eligible for analysis, median KDPI was 54 (interquartile range [IQR], 31–77), and Kidney Donor Risk Index was 1.39 (IQR, 1.03–1.67). The median 1-y eGFR was 52.74 mL/min (IQR, 40.79–66.41 mL/min). Compared with the first quintile reference group, progressive reductions in eGFR were observed with increasing KDPI and were maximal in the fifth quintile (adjusted β-coefficient: −27.43 mL/min; 95% confidence interval, –29.44 to –25.42; P < 0.001). A suboptimal outcome was observed in 359 recipients (12.3%). The adjusted odds for this outcome increased across quintiles from a baseline of odds ratio of 1.00 (first quintile) to odds ratio of 11.68 (95% confidence interval, 6.33-21.54, P < 0.001) in the fifth quintile cohort.

Conclusions.

Increases in donor KDPI were associated with higher probabilities of a suboptimal outcome and poorer baseline allograft function, particularly in the KDPI > 80 cohort. These findings may inform pretransplant discussions with potential recipients of high-KDPI allografts.

Does prolonged cold ischemia affect outcomes in donation after cardiac death donor kidney transplants?

    : The purpose of this study was to analyze the combined effect of cold ischemia time (CIT) and donation after cardiac death (DCD, with requisite warm ischemia time, WIT) on kidney transplant (KT) outcomes.

METHODS

Single center retrospective review of DCD KT recipients stratified by CIT.

RESULTS

From 6/08 to 10/20, we performed 446 DCD KTs (115 CIT ≤20, 205 CIT 20-30, 88 CIT 30-40, 38 CIT ≥40 hours). Mean WITs (26/25/27/23 minutes) and KDPI values (59%/55%/55%/59%) were similar while mean CITs (16.4/23.6/33.4/42.5 hours) and pump times (10.3/13.6/16.1/20.4 hours) differed across groups (p < 0.05). With a mean 6-year follow-up, patient survival (84%/84%/74%/84%) was similar. Kidney graft survival (GS) (72%/72%/56%/58%) and death censored GS (DCGS) (82%/80%/63%/67%) rates decreased whereas rates of primary nonfunction (PNF, 0.9%/2.4%/9.1%/7.9%) and delayed graft function (DGF) (36%/48%/50%/69%) increased with longer CIT (≥30 hours, p<0.05). Meaningful years free of dialysis, which we refer to as Allograft Life Years, were achieved in all cohorts (4.5/4.3/3.9/4.3 years per patient transplanted).

CONCLUSION

DCD donor kidneys with prolonged CIT (≥30 hours) are associated with increased rates of DGF and PNF, along with decreased GS and DCGS. Despite this, Allograft Life Years were gained even with longer CITs, demonstrating the utility of using these allografts. This article is protected by copyright. All rights reserved.

Trends in the procurement and discard of kidneys from deceased donors with acute kidney injury

Kidney allocation trends from deceased donors with acute kidney injury (AKI) have not been characterized since initial Kidney Donor Profile Index reporting in 2012 and its use under the revised Kidney Allocation System (KAS) in 2014. We conducted a retrospective analysis of US registry data to characterize kidney procurement and discard trends in deceased donors with AKI, defined by ≥50% or ≥0.3 mg/dl (≥4.0 mg/dl or ≥200% for stage 3) increase in terminal serum creatinine from admission. From 2010 to 2020, 172 410 kidneys were procured from 93 341 deceased donors 16 years or older; 34 984 kidneys were discarded (17 559 from AKI donors). The proportion of stage 3 AKI donors doubled from 6% (412/6841) in 2010 to 12% (1365/11493) in 2020. Procurement of stage 3 AKI kidneys increased from 51% (423/824) to 80% (2183/2730). While discard of stage 3 AKI kidneys increased from 41% (175/423) in 2010 to 44% (960/2183) in 2020, this increase was not statistically significant in interrupted time-series analysis following KAS implementation (slope difference -0.41 [-3.22, 2.4], and level change 3.09 [-6.4, 12.6]). In conclusion, the absolute number of stage 3 AKI kidneys transplanted has increased. Ongoing high discard rates of these kidneys suggest opportunities for improved utilization.

The use of marginal kidneys in dual kidney transplantation to expand kidney graft utilization

PURPOSE OF REVIEW

The purpose of this review is to chronicle the history of dual kidney transplantation (DKT) and identify opportunities to improve utilization of marginal deceased donor (MDD) kidneys through DKT.

RECENT FINDINGS

The practice of DKT from adult MDDs dates back to the mid-1990s, at which time the primary indication was projected insufficient nephron mass from older donors. Multiple subsequent studies of short- and long-term success have been reported focusing on three major aspects: Identifying appropriate selection criteria/scoring systems based on pre- and postdonation factors; refining technical aspects; and analyzing longer-term outcomes. The number of adult DKTs performed in the United States has declined in the past decade and only about 60 are performed annually. For adult deceased donor kidneys meeting double allocation criteria, >60% are ultimately not transplanted. MDDs with limited renal functional capacity represent a large proportion of potential kidneys doomed to either discard or nonrecovery.

SUMMARY

DKT may reduce organ discard and optimize the use of kidneys from MDDs. New and innovative technologies targeting ex vivo organ assessment, repair, and regeneration may have a major impact on the decision whether or not to use recovered kidneys for single or DKT.

Patient and Clinician Perceptions of Informed Consent and Decision Making About Accepting KDPI > 85 Kidneys

Supplemental Digital Content is available in the text.

Background.

Although the impact of the kidney donor profile index (KDPI) on kidney discard is well researched, less is known about how patients make decisions about whether to give consent for KDPI > 85 kidney offers.

Methods.

We conducted in-depth, semistructured interviews with 16 transplant recipients, 15 transplant candidates, and 23 clinicians (transplant surgeons, nephrologists, and nurse coordinators) to assess and compare perceptions of transplant education, informed consent for KDPI > 85 kidneys‚ and the decision-making process for accepting kidney offers. Thematic analysis was used to analyze qualitative data.

Results.

Four themes emerged: (1) patients reported uncertainty about the meaning of KDPI or could not recall information about KDPI; (2) patients reported uncertainty about their KDPI > 85 consent status and a limited role in KDPI > 85 consent decision making; (3) patients’ reported willingness to consider KDPI > 85 kidneys depended on their age, health status, and experiences with dialysis, and thus it changed over time; (4) patients’ underestimated the survival benefit of transplantation compared with dialysis, which could affect their KDPI > 85 consent decision making.

Conclusions.

To better support patients’ informed decision making about accepting KDPI > 85 kidneys, centers must ensure that all patients receive education about the trade-offs between accepting a KDPI > 85 kidney and remaining on dialysis. Additionally, education about KDPI and discussions about informed consent for KDPI > 85 kidneys must be repeated at multiple time points while patients are on the waiting list.

Dual kidney transplants from adult marginal donors: Review and perspective

The practice of dual kidney transplantation (DKT) from adult marginal deceased donors (MDDs) dates back to the mid-1990s with initial pioneering experiences reported by the Stanford and Maryland groups, at which time the primary indication was estimated insufficient nephron mass from older donors. Multiple subsequent studies of short and long-term success have been reported focusing on three major aspects of DKT: Identifying appropriate selection criteria and developing scoring systems based on pre- and post-donation factors; refining technical aspects; and analyzing mid-term outcomes. The number of adult DKTs performed in the United States has declined in the past decade and only about 60 are performed annually. For adult deceased donor kidneys meeting double allocation criteria, >60% are ultimately not transplanted. Deceased donors with limited renal functional capacity represent a large proportion of potential kidneys doomed to either discard or non-recovery. However, DKT may reduce organ discard and optimize the use of kidneys from MDDs. In an attempt to promote utilization of MDD kidneys, the United Network for Organ Sharing introduced new allocation guidelines pursuant to DKT in 2019. The purpose of this review is to chronicle the history of DKT and identify opportunities to improve utilization of MDD kidneys through DKT. This article is protected by copyright. All rights reserved.

Body Mass Index and Kidney Donor Profile Index as Prognostic Markers of the Outcome of Renal Transplantation

BACKGROUND

The aim of this study was to determine the effects of Kidney Donor Profile Index (KDPI) and body mass index (BMI) of the deceased donor on the kidney allograft outcome 1 year after transplantation.

METHODS

We retrospectively studied 98 deceased kidney allograft donors with a mean age of 56 ± 12 years. The donors were divided into 5 groups according to their BMI: Normal ΒΜΙ = 25 (n = 25); ΒΜΙ 25 to 29 = Overweight (n = 33); ΒΜΙ 30 to 34.9 = Obese class I (n = 19); ΒΜΙ 35 to 39 = Obese class ΙΙ (n = 11); and ΒΜΙ >40 = Obese class III (n = 10). We examined the impact of the deceased donor's BMI and KDPI on delayed graft function (DGF) and estimated renal glomerular filtration rate (eGFR) (measured by the Chronic Kidney Disease Epidemiology Collaboration equation) 1 year after transplantation.

RESULTS

Donor BMI significantly increased the prevalence of DGF (P = .031), and it was associated with higher cold ischemia time (P = .021). However, there was no significant association between the aforementioned BMI groups and 1-year eGFR (P = 0.57), as deceased grafts from donors with increased BMI (BMI > 40) gained sufficient renal function during the first year of transplantation. Moreover, high KDPI was associated not only with DGF (P = .015), but also with decreased values of eGFR (P = .033).

CONCLUSION

In this population, we identified no significant association between donor BMI and long-term clinical outcomes in deceased donor kidney transplants. KDPI, and not ΒΜΙ, of the deceased donor seems to be a good prognostic factor of renal function at the end of the first year after kidney transplant, whereas high BMI and high KDPI markedly induce DGF.

Disparities in Deceased Organ Donor Research Authorization: Experience at One Organ Procurement Organization and Call for National Conversations

Introduction

Research with deceased donor organs can provide an important platform for studying interventions to improve organ use and outcomes after authorization from the next-of-kin (NOK) or before death by the decedent (i.e., first-person authorization [FPA]). To date, information on authorization rates across donor subgroups is lacking.

Methods

We performed a retrospective chart review of all 690 deceased organ donors from January 2017 to December 2019 at a midsized Midwestern organ procurement organization (OPO). Multivariable logistic regression was used to assess associations between donor factors and research decline (adjusted odds ratio [aOR], 95% confidence interval [CI]).

Results

Electronic records for all 690 deceased donors were reviewed. Of these, 659 (95.5%) yielded at least one transplanted organ. Overall, research was declined in 10.8% of donations. Compared to White donors, research decline was higher for Black (16.0% vs. 8.9%; aOR, 1.87; 95% CI, 1.03-3.40; P = 0.04) and other non-White donors (24.0% vs. 8.9%; aOR, 4.21; 95% CI, 1.02-17.39; P = 0.05). Unadjusted research decline trended higher for Hispanic donors versus non-Hispanic donors (23.1% vs. 10.5%; P = 0.14). Compared to donors age <40 years, research decline trended higher for donors age ≥65 years (16.7% vs. 11.8%; aOR, 4.87; 95% CI, 1.12-21.05; P = 0.03), whereas research decline was 55% lower when donors provided FPA (7.3% vs 15.0%; aOR, 0.45; 95% CI, 0.27-0.76; P = 0.003).

Conclusions

Deceased donor research authorization decline is higher for Black, other non-White, and older donors, but lower when the descendent provides FPA. Identification of disparities in research authorization may stimulate educational strategies to reduce barriers to scientific investigations directed at optimizing the outcomes of organ donation.

Accuracy of risk models used for public reporting of heart transplant center performance

BACKGROUND

Heart transplant programs and regulatory entities require highly accurate performance metrics to support internal quality improvement activities and national oversight of transplant programs, respectively. We assessed the accuracy of publicly reported performance measures.

METHODS

We used the United Network for Organ Sharing registry to study patients who underwent heart transplantation between January 1, 2016 and June 30, 2018. We used tests of calibration to compare the observed rate of 1-year graft failure to the expected risk of 1-year graft failure, which was calculated for each recipient using the July 2019 method published by the Scientific Registry of Transplant Recipients (SRTR). The primary study outcome was the joint test of calibration, which accounts for both the total number of events predicted (calibration-in-the-large) and dispersion of risk predictions (calibration slope).

RESULTS

6,528 heart transplants were analyzed. The primary test of calibration failed (p <0.0001), indicating poor accuracy of the SRTR model. The calibration-in-the-large statistic (0.63, 95% confidence interval [CI] 0.58-0.68, p < 0.0001) demonstrated overestimation of event rates while the calibration slope statistic (0.56, 95% CI 0.49-0.62, p <0.0001) indicated over-dispersion of event rates. Pre-specified subgroup analyses demonstrated poor calibration for all subgroups (each p <0.01). After recalibration, program-level observed/expected ratios increased by a median of 0.14 (p <0.0001).

CONCLUSIONS

Risk models employed for publicly-reported graft survival at U.S. heart transplant centers lack accuracy in general and in all subgroups tested. The use of disease-specific models may improve the accuracy of program performance metrics.

Outcomes and factors leading to graft failure in kidney transplants from deceased donors with acute kidney injury-A retrospective cohort study

Due to shortage of donor, kidney transplants (KTs) from donors with acute kidney injury (AKI) are expanding. Although previous studies comparing clinical outcomes between AKI and non-AKI donors in KTs have shown comparable results, data on high-volume analysis of KTs outcomes with AKI donors are limited. This study aimed to analyze the selection trends of AKI donors and investigate the impact of AKI on graft failure using the United states cohort data. We analyzed a total 52,757 KTs collected in the Scientific Registry of Transplant Recipient (SRTR) from 2010 to 2015. The sample included 4,962 (9.4%) cases of KTs with AKI donors (creatinine ≥ 2 mg/dL). Clinical characteristics of AKI and non-AKI donors were analyzed and outcomes of both groups were compared. We also analyzed risk factors for graft failure in AKI donor KTs. Although the incidence of delayed graft function was higher in recipients of AKI donors compared to non-AKI donors, graft and patient survival were not significantly different between the two groups. We found donor hypertension, cold ischemic time, the proportion of African American donors, and high KDPI were risk factors for graft failure in AKI donor KTs. KTs from deceased donor with AKI showed comparable outcomes. Thus, donors with AKI need to be considered more actively to expand donor pool. Caution is still needed when donors have additional risk factors of graft failure.

Technology-Enabled Care and Artificial Intelligence in Kidney Transplantation

Purpose of Review

Artificial intelligence (AI), machine learning, and technology-enabled remote patient care have evolved rapidly and have now been incorporated into many aspects of medical care. Transplantation is fortunate to have large data sets upon which machine learning algorithms can be constructed. AI are now available to improve pretransplant management, donor selection, and post-operative management of transplant patients.

Recent Findings

Changes in patient and donor characteristics warrant new approaches to listing and organ acceptance practices. Machine learning has been employed to optimize donor selection to identify patients likely to benefit from transplantation of higher risk organs, increasing organ discard and reducing waitlist mortality. These models have greater precisions and predictive ability than currently employed metrics including the Kidney Donor Profile Index and the expected posttransplant survival models. After transplant, AI tools have been developed to optimize immunosuppression management, track patients adherence, and assess graft survival.

Summary

AI and technology-enabled management tools are now available throughout the transplant journey. Unfortunately, those are frequently not available at the point of decision (patient listing, organ acceptance, posttransplant clinic), limiting utilization. Incorporation of these tools into the EMR, the Donor Net® organ offer system, and mobile devices is vital to ensure widespread adoption.

A Roadmap for Innovation to Advance Transplant Access and Outcomes: A Position Statement From the National Kidney Foundation

Over the past 65 years, kidney transplantation has evolved into the optimal treatment for patients with kidney failure, dramatically reducing suffering through improved survival and quality of life. However, access to transplant is still limited by organ supply, opportunities for transplant are inequitably distributed, and lifelong transplant survival remains elusive. To address these persistent needs, the National Kidney Foundation convened an expert panel to define an agenda for future research. The key priorities identified by the panel center on the needs to develop and evaluate strategies to expand living donation, improve waitlist management and transplant readiness, maximize use of available deceased donor organs, and extend allograft longevity. Strategies targeting the critical goal of decreasing organ discard that warrant research investment include educating patients and clinicians about potential benefits of accepting nonstandard organs, use of novel organ assessment technologies and real-time decision support, and approaches to preserve and resuscitate allografts before implantation. The development of personalized strategies to reduce the burden of lifelong immunosuppression and support "one transplant for life" was also identified as a vital priority. The panel noted the specific goal of improving transplant access and graft survival for children with kidney failure. This ambitious agenda will focus research investment to promote greater equity and efficiency in access to transplantation, and help sustain long-term benefits of the gift of life for more patients in need.

No Benefit of Prophylactic Surgical Drainage in Combined Liver and Kidney Transplantation: Our Experience and Review of the Literature

Background: Contrasting results have emerged from limited studies investigating the role of prophylactic surgical drainage in preventing wound morbidity after liver and kidney transplantation. This retrospective study analyzes the use of surgical drain and the incidence of wound complications in combined liver and kidney transplantation (CLKTx).

Methods: A total of 55 patients aged ≥18 years were divided into two groups: the drain group (D) (n = 35) and the drain-free group (DF) (n = 20). Discretion to place a drain was based exclusively on surgeon preference. All deceased donor kidneys were connected to the LifePort Renal Preservation Machine® prior to transplantation, in both simultaneous and delayed technique of implantation of the renal allograft. The primary outcome was the development of superficial/deep wound complications during the study follow-up. Secondary outcomes included the development of delayed graft function (DGF) of the transplanted kidney, primary non-function (PNF) and early allograft dysfunction (EAD) of the transplanted liver, graft failure, graft and patient survival, overall post-operative morbidity rate and length of hospital stay.

Results: With a median follow-up of 14.4 months after transplant, no difference in the incidence of superficial/deep wound complications, except for hematomas, in collections size, intervention rate, PNF, EAD, graft failure and patient survival, was observed between the 2 groups. Significantly lower level of platelets, higher INR values, DGF, morbidity rates and length of hospital stay were reported post-operatively in the D group. Pre-operative hypoalbuminemia and longer CIT were included in the propensity score for receiving a drain and were associated with a significantly higher rate of developing a hematoma post-transplant.

Conclusions: Absence of the surgical drain did not appear to adversely affect wound morbidity compared to the prophylactic use of drains in renal transplant patients during CLKTx.

A kidney discard decision strategy based on zero-time histology analysis could lead to an unjustified increase in the organ turndown rate among ECD

The utility of zero-time kidney biopsies (KB) in deciding to accept expanded criteria donor (ECD) kidneys remains controversial. However, zero-time histology is one of the main causes for discarding kidneys in the United States. In a single-centre study, we examined the utility and impact on outcome of the use of frozen section zero-time KB among ECD. Ninety-two zero-time KB were analysed for accept/discard decision between 2005 and 2015 among ECD. 53% of kidneys were rejected after zero-time KB analysis; there was no difference in individual clinical and biological data between accepted/rejected groups. However, histology of rejected kidneys showed more sclerotic glomeruli (20% vs. 8%; P < 0.001), increased interstitial fibrosis (1.25 ± 0.12 vs. 0.47 ± 0.09; P < 0.0001), more arteriosclerosis (2.14 ± 0.17 vs. 1.71 ± 0.11; P = 0.0032) and arteriolar hyalinosis (2.15 ± 0.12 vs. 1.55 ± 0.11; P = 0.0006). Using propensity score matching, we generated a group of 42 kidney allograft recipients who received a transplant matched for donor zero-time histology and clinical characteristics with donors whose kidneys were rejected. Interestingly, their 1- and 5-year graft survival and function were similar to the global cohort of ECD recipients. In conclusion, when performed, zero-time KB was a decisive element for kidney discard decision. However, adverse zero-time histology was not associated with poorer graft survival and kidney function among ECD.

Correlation of Chronic Histologic Changes on Preimplantation Frozen Section Biopsy With Transplant Outcomes After Deceased Donor Kidney Transplantation

CONTEXT.—

It is unclear if preimplantation frozen section biopsy correlates with outcomes after deceased donor kidney transplantation.

OBJECTIVE.—

To assess if chronic histologic changes on the preimplant frozen section correlates with graft loss and estimated glomerular filtration rate independently of kidney donor profile index (KDPI).

DESIGN.—

Seven hundred three preimplantation biopsies were reviewed and a Banff sum score was calculated using glomerular sclerosis, interstitial fibrosis, vascular intimal thickening, and arteriolar hyalinosis. The posttransplant outcomes were compared for preimplantation biopsy Banff sum 0-1, 2-3, and 4-9. The cohort was also stratified by KDPI 85 or less versus more than 85.

RESULTS.—

For the entire biopsy cohort, graft survival, estimated glomerular filtration rate at 1 year and chronic changes on a 1-year posttransplant biopsy were superior in the group with preimplantation Banff sum 0-1. After stratifying by KDPI, the Banff sum no longer correlated with graft survival. In a univariate mode, using the Banff sum score as a continuous variable, a higher Banff sum score was significantly associated with graft failure (P = .03); however, after adjusting the KDPI, the Banff sum score no longer correlated with graft failure (P = .45). The 1-year estimated glomerular filtration rate and 1 year biopsy changes were superior in the group with Banff sum 0-1 only in the cohort with KDPI 85 or less.

CONCLUSIONS.—

In donor kidneys used for transplant, preimplantation biopsy chronic changes correlate with estimated glomerular filtration rate and biopsy findings at 1 year, but biopsies with mostly mild chronicity and sum scores less than or equal to 5 did not impact graft survival beyond KDPI.

DCD Renal Transplantation From Donors With Acute Kidney Injury

BACKGROUND

Deceased donor kidneys with acute kidney injury (AKI) and donation after circulatory death (DCD) kidneys are viable sources of organs. The outcomes of renal transplantation from DCD donors with AKI are not known.

METHODS

A retrospective review of deceased donor renal transplants performed from 2006 to 2016 was conducted using the United Network for Organ Sharing dataset. Donors were stratified by DCD or brain dead status and by AKI stage. Recipients were followed until graft failure or the end of study. Cox regression was used to adjust for donor, recipient, and transplant covariates known to affect the incidence of delayed graft function and graft survival.

RESULTS

A total of 135 644 patients were included in the study. The odds of delayed graft function among DCD recipients were significantly higher across all donor AKI stages. The unadjusted risk of overall and death-censored graft failure were similar between the 2 groups. After adjusting for covariates, there was a significant increase in the risk of overall graft failure in recipients of DCD allografts from donors with stage 2 AKI. There was also a higher risk of death-censored graft failure among stage 1 and 2 AKI DCD recipients.

CONCLUSIONS

DCD renal allografts from donors experiencing stage 1 and 2 AKI have a higher adjusted risk of death-censored graft failure than AKI stage-matched donation after brain death renal allografts. Their use, however, is still associated with improved outcomes compared with waitlist mortality.

Impact of acute kidney injury in deceased donors with high Kidney Donor Profile Index on posttransplant clinical outcomes: a multicenter cohort study

BACKGROUND

This study evaluated the impact of acute kidney injury (AKI) on posttransplant clinical outcomes for deceased donor (DD) kidney transplantation (KT) using the Kidney Donor Profile Index (KDPI) system.

METHODS

Overall, 657 kidney transplant recipients (KTRs) receiving kidneys from 526 DDs from four transplant centers were included. We divided them into the high and low KDPI donor groups by 65%, the KDPI score, and both groups were subdivided into the AKI-DDKT and non-AKI-DDKT subgroups according to AKI in DDs.

RESULTS

There was no significant difference in the incidence of delayed graft function (DGF) between the high and low KDPI-KTR groups; however, the AKI-DDKT subgroup showed significantly higher incidence of DGF than the non-AKI-DDKT subgroup in both groups (p = 0.001, p < 0.001, respectively). The death-censored graft survival rate was significantly lower in the high KDPI-KTR group than in the low KDPI-KTR group (p = 0.005). Only in the high KDPI-KTR group, the death-censored graft survival rate was significantly lower in the KT from DDs with AKI stage 3 than KT from DDs with non-AKI or AKI stage 1 or 2 (p = 0.040). The interaction between AKI stage 3 in DDs and high KDPI on the allograft outcome was significant (p = 0.002).

CONCLUSION

KTs from DDs with AKI stage 3 showed an adverse impact on the allograft outcome in the high KDPI-KTR group. Therefore, DDs with a high KDPI score should be managed carefully so that severe AKI does not occur prior to KT.

Use of expanded-criteria donors and > 85 KDPI kidneys for pediatric kidney transplantation in the United States

Pediatric kidney transplant outcomes associated with expanded-criteria donors (ECD) and high Kidney Donor Profile Index (KDPI) kidneys are unknown. We reviewed the Scientific Registry of Transplant Recipients data from 1987-2017 to identify 96 ECD and 92 > 85 KDPI kidney recipients (<18 years). Using propensity scores, we created comparison groups of 375 non-ECD and 357 ≤ 85 KDPI recipients for comparisons with ECD and > 85 KDPI transplants, respectively. We used Cox regression for patient/graft survival and sequential Cox approach for survival benefit of ECD and > 85 KDPI transplantationvs remaining on the waitlist. After adjustment, ECD recipients were at significantly increased risk of graft failure (adjusted hazard ratio [aHR] = 1.6; P = .001) but not of mortality (aHR = 1.33; P = .15) compared with non-ECD recipients. We observed no survival benefit of ECD transplants vs remaining on the waitlist (aHR = 1.05; P = .83). We found no significant difference in graft failure (aHR = 1.27; P = .12) and mortality (aHR = 1.41; P = .13) risks between > 85 KDPI and ≤ 85 KDPI recipients. However, > 85 KDPI transplants were associated with a survival benefit vs remaining on the waitlist (aHR = 0.41; P = .01). ECD transplantation in children is associated with a high graft loss risk and no survival benefit, whereas > 85 KDPI transplantation is associated with a survival benefit for children vs remaining on the waitlist.

Prediction of Kidney Allograft Discard Before Procurement: The Kidney Discard Risk Index

OBJECTIVES

There is an 18.9% discard rate among kidney allografts. Here, we aimed to determine predictors of kidney discard and construct an index to identify high-probability discard kidney allografts prior to procurement.

MATERIALS AND METHODS

A total of 102 246 potential kidney allograft donors from the Organ Procurement and Transplantation Network database were used in this analysis. The cohort was randomized into 2 groups. The training set included 67% of the cohort and was used to derive a predictive index for discard that comprised 21 factors identified by univariate and multivariate logistic regression analysis. The validation set included 33% and was used to internally validate the kidney discard risk index.

RESULTS

In 77.3% of donors, at least 1 kidney was used for transplant, whereas in 22.7% of donors, both kidneys were discarded. The kidney discard risk index was highly predictive of discard with a C statistic of 0.89 (0.88-0.89). The bottom 10th percentile had a discard rate of 0.73%, whereas the top 10th percentile had a discard rate of 83.65%. The 3 most predictive factors for discard were age, creatinine level, and hepatitis C antibody status.

CONCLUSIONS

We identified 21 factors predictive of discard prior to donor procurement and used these to develop a kidney discard risk index with a C statistic of 0.89.

Preimplantation Histological Score Associates with 6-Month GFR in Recipients of Perfused, Older Kidney Grafts: Results from a Pilot Study

BACKGROUND

Biopsy-guided selection of older kidneys safely expands the organ pool, and pretransplant perfusion improves the preservation of these fragile organs. Herein, we studied morphofunctional variables associated with graft outcomes in perfused, histologically evaluated older kidneys.

METHODS

This single-center prospective cohort pilot study evaluated the relationships between preimplantation histologic scores and renal perfusion parameters during hypothermic, pulsatile, machine perfusion (MP) and assessed whether these morphofunctional parameters associated with GFR (iohexol plasma clearance) at 6 months after transplantation in 20 consecutive consenting recipients of a biopsy-guided single or dual kidney transplant from >60-year-old deceased donors.

RESULTS

The donor and recipient age was 70.4 ± 6.5 and 63.6 ± 7.9 years (p = 0.005), respectively. The kidney donor profile index (KDPI) was 93.3 ± 8.4% (>80% in 19 cases), histologic score 4.4 ± 1.4, and median (IQR) cold ischemia time 19.8 (17.8-22.8 h; >24 h in 5 cases). The 6-month GFR was 41.2 (34.9-55.7) mL/min. Vascular resistances positively correlated with global histologic score (p = 0.018) at MP start and then decreased from 0.88 ± 0.43 to 0.36 ± 0.13 mm Hg/mL/min (p < 0.001) in parallel with a three-fold renal flow increase from 24.0 ± 14.7 to 74.7 ± 31.8 mL/min (p < 0.001). Consistently, vascular resistance reductions positively correlated with global histologic score (p = 0.009, r = -0.429). Unlike KDPI or vascular resistances, histologic score was independently associated with 6-month GFR (beta standardized coefficient: -0.894, p = 0.005).

CONCLUSIONS

MP safely improves graft perfusion, particularly in kidneys with severe histologic changes that would not be considered for transplantation because of high KDPI. The preimplantation histologic score associates with the functional recovery of older kidneys even in the context of a standardized program of pulsatile perfusion.

A Simulation-Based Optimization Model to Study the Impact of Multiple-Region Listing and Information Sharing on Kidney Transplant Outcomes

More than 8000 patients on the waiting list for kidney transplantation die or become ineligible to receive transplants due to health deterioration. At the same time, more than 4000 recovered kidneys from deceased donors are discarded each year in the United States. This paper develops a simulation-based optimization model that considers several crucial factors for a kidney transplantation to improve kidney utilization. Unlike most proposed models, the presented optimization model incorporates details of the offering process, the deterioration of patient health and kidney quality over time, the correlation between patients’ health and acceptance decisions, and the probability of kidney acceptance. We estimate model parameters using data obtained from the United Network of Organ Sharing (UNOS) and the Scientific Registry of Transplant Recipients (SRTR). Using these parameters, we illustrate the power of the simulation-based optimization model using two related applications. The former explores the effects of encouraging patients to pursue multiple-region waitlisting on post-transplant outcomes. Here, a simulation-based optimization model lets the patient select the best regions to be waitlisted in, given their demand-to-supply ratios. The second application focuses on a system-level aspect of transplantation, namely the contribution of information sharing on improving kidney discard rates and social welfare. We investigate the effects of using modern information technology to accelerate finding a matching patient to an available donor organ on waitlist mortality, kidney discard, and transplant rates. We show that modern information technology support currently developed by the United Network for Organ Sharing (UNOS) is essential and can significantly improve kidney utilization.

Donor-Recipient Matching to Optimize the Utility of High Kidney Donor Profile Index Kidneys

BACKGROUND

In December 2014, the Kidney Donor Profile Index (KDPI) was developed to give more precise information on donor kidney quality. Kidneys with KDPI scores ≥ 85 (K ≥ 85) have been reported to have inferior outcomes to kidneys with KDPI scores < 85.

METHODS

After the implementation of the new Kidney Allocation System, we developed a protocol to evaluate K ≥ 85 use. We analyzed the safety and efficacy of our institutional criteria and evaluated post-transplant outcomes. K ≥ 85 recipients were stratified based on their 1-year creatinine and estimated glomerular filtration rates to elucidate characteristics associated with serum creatinine < 1.7 mg/dL or estimated glomerular filtration rates ≤ 45 mL/min/1.73 m².

RESULTS

From December 2014 to December 2019, 304 deceased donor kidney transplants were performed at Hartford Hospital; 58 (19%) were K ≥ 85 with an average KDPI of 91%. There were 4 graft losses; 2 were death censored. Prolonged cold ischemia time and black recipient race were associated with inferior recipient graft function at 1 year.

CONCLUSIONS

High KDPI kidney use requires a multifaceted evaluation that takes into account donor and recipient characteristics for an ideal match. We have identified several characteristics that may predict optimal post-transplant kidney function.