Kidney Allocation Research Articles

Increasing Incidence of Out-of-Sequence Allocation of Deceased-Donor Kidneys

Increasing Incidence of Out-of-Sequence Allocation of Deceased-Donor Kidneys

Variation Across Organ Procurement Organizations in Deceased-Donor Kidney Offer Notification Practices.

How offer notifications are distributed early in the kidney allocation timeline, including how widely they are offered, is unclear. A better understanding of offer notification practices across organ procurement organizations (OPOs) may identify opportunities for more efficient allocation. We merged the Scientific Registry of Transplant Recipients potential transplant recipient file with additional offer notification time stamps to identify 54631 deceased-donor kidney match runs from 2017 to 2023. Offer notifications for a given match run are sent to candidates/centers in "batches." We quantified the number of offers in the initial batch-which theoretically reflects the OPO's initial estimate of how widely a kidney should be offered-and compared this metric across OPOs. Kidneys were offered to a median of 14 candidates (IQR 9-38) in the first batch of notifications, and this varied across OPOs from 3 to 746 candidates per initial batch. Batch size at the OPO-level did not correlate with rank at kidney placement or OPO nonuse rate. OPOs in the highest quartile of batch size sent more offers (median 100) than presumably necessary to place kidneys (median rank at placement 21), and OPOs in the lowest quartile of batch size sent fewer offers (6) than needed to place kidneys (rank at placement 19). Offer notification practices vary widely across OPOs, and many OPOs offer kidneys far more widely than necessary for placement. Optimization of offer notification practices may reduce unnecessary communications. Further research into allocation processes is needed to identify opportunities to improve efficiency of allocation for OPOs and transplant centers.

A novel two-stage network data envelopment analysis model for kidney allocation problem under medical and logistical uncertainty: a real case study.

Organ transplantation is one of the most complicated and challenging treatments in healthcare systems. Despite the significant medical advancements, many patients die while waiting for organ transplants because of the noticeable differences between organ supply and demand. In the organ transplantation supply chain, organ allocation is the most significant decision during the organ transplantation procedure, and kidney is the most widely transplanted organ. This research presents a novel method for assessing the efficiency and ranking of qualified organ-patient pairs as decision-making units (DMUs) for kidney allocation problem in the existence of COVID-19 pandemic and uncertain medical and logistical data. To achieve this goal, two-stage network data envelopment analysis (DEA) and credibility-based chance constraint programming (CCP) are utilized to develop a novel two-stage fuzzy network data envelopment analysis (TSFNDEA) method. The main benefits of the developed method can be summarized as follows: considering internal structures in kidney allocation system, investigating both medical and logistical aspects of the problem, the capability of expanding to other network structures, and unique efficiency decomposition under uncertainty. Moreover, in order to evaluate the validity and applicability of the proposed approach, a validation algorithm utilizing a real case study and different confidence levels is used. Finally, the numerical results indicate that the developed approach outperforms the existing kidney allocation system.

Associations Among Circle-Based Kidney Allocation, Center Waiting Time, and Likelihood of Deceased-Donor Kidney Transplantation

The kidney allocation system (KAS250), using circle-based distribution, attempts to address geographic disparities through broader sharing of deceased-donor kidney allografts. This study sought to evaluate the association between KAS250 and likelihood of deceased-donor kidney transplantation (DDKT) among waitlisted candidates, and whether the policy has differentially affected centers with shorter vs. longer waiting time. Retrospective cohort study. & Participants: 160,941 candidates waitlisted at 176 transplant centers between 3/2017-3/2024. KAS250 allocation policy. Rate of DDKT. Multivariable Cox regression, modeling KAS250 as a time-dependent variable. KAS250 was not independently associated with likelihood of DDKT overall (HR=1.01 vs. pre-KAS250, 95% C.I. 0.97-1.04). KAS250's association with likelihood of DDKT varied across centers from HR=0.18 (DDKT less likely after KAS250) to HR=17.12 (DDKT more likely) and varied even among neighboring centers. KAS250 was associated with decreased DDKT at 25.6% and increased DDKT at 18.2% of centers. Centers with previously long median waiting times (57+ months) experienced increased likelihood of DDKT after KAS250 (HR=1.20, 95% C.I. 1.15-1.26), whereas centers with previously short median waiting times (6-24mo.; HR=0.88, 0.84-0.92) experienced decreased likelihood of DDKT. Retrospective study of allocation policy changes, confounded by multiple changes over the study timeframe. Association between KAS250 and DDKT varied across centers. For one-in-four centers, DDKT was less likely after KAS250 relative to pre-KAS250 trends. Candidates at centers with previously long waiting times experienced increased likelihood of DDKT after KAS250. Thus, broader distribution of kidneys may be associated with improved equity in access to DDKT, but additional strategies may be needed to minimize disparities between centers.

Personal Viewpoint: Navigating Challenges in Recipient Selection for End-Chain Kidneys

As a result of the increasing number of transplants being facilitated by kidney paired donation, and newer initiatives such as voucher donation, end-chain kidneys now constitute a considerable proportion of kidney paired donation transplants in the United States. Data on end-chain kidneys are limited. They may be lower in quality compared to non-end chain living donor kidneys. However, they can provide unique opportunities for recipient candidates without living donors. There are no data or algorithms available to guide recipient selection for end-chain kidneys accepted by a transplant center. Considering the ethical principles of utility, justice, and respect for persons that underlie organ allocation, we discuss three potential approaches for recipient selection: 1) adherence to the Kidney Allocation System, 2) utility maximization and 3) priority to high-risk candidates, along with examples from our own center’s experience. Similar considerations are also relevant to selection of recipients for non-directed donor organs, and to out-of-sequence allocation for deceased organ donors. Since end-chain kidneys represent an increasingproportion of kidney paired donation-facilitated living kidney donor transplantation in the United States, and will likely get more medically and surgically complex over time, ongoing research on their utilization and outcomes is needed.

Advancing Kidney Transplantation: A Machine Learning Approach to Enhance Donor-Recipient Matching.

(1) Background: Globally, the kidney donor shortage has made the allocation process critical for patients awaiting a kidney transplant. Adopting Machine Learning (ML) models for donor-recipient matching can potentially improve kidney allocation processes when compared with traditional points-based systems. (2) Methods: This study developed an ML-based approach for donor-recipient matching. A comprehensive evaluation was conducted using ten widely used classifiers (logistic regression, decision tree, random forest, support vector machine, gradient boosting, boost, CatBoost, LightGBM, naive Bayes, and neural networks) across three experimental scenarios to ensure a robust approach. The first scenario used the original dataset, the second used a merged version of the dataset, and the last scenario used a hierarchical architecture model. Additionally, a custom ranking algorithm was designed to identify the most suitable recipients. Finally, the ML-based donor-recipient matching model was integrated into a web-based platform called Nephron. (3) Results: The gradient boost model was the top performer, achieving a remarkable and consistent accuracy rate of 98% across the three experimental scenarios. Furthermore, the custom ranking algorithm outperformed the conventional cosine and Jaccard similarity methods in identifying the most suitable recipients. Importantly, the platform not only facilitated efficient patient selection and prioritisation for kidney allocation but can be flexibly adapted for other solid organ allocation systems built on similar criteria. (4) Conclusions: This study proposes an ML-based approach to optimize donor-recipient matching within the kidney allocation process. Successful implementation of this methodology demonstrates significant potential to enhance both efficiency and fairness in kidney transplantation.

328.2: ABO-compatible US kidney allocation with ABO-adjusted CPRA.

328.2: ABO-compatible US kidney allocation with ABO-adjusted CPRA.

Highly Sensitized Kidney Transplant Outcomes After the 2014 Kidney Allocation System Change.

Introduction: Kidney Allocation System (KAS) was implemented by United Network for Organ Sharing in 2014 to reduce allocation disparities. Research Questions: Outcomes of highly sensitized patients (calculated panel reactive antibody (cPRA) ≥ 97%) before and after KAS were compared to low-risk recipients (cPRA <10%) in the post-KAS era were examined. The impact on racial disparities was determined. Design: This was a retrospective study of national registry data. Two cohorts of adult candidates waitlisted for deceased donor transplantation during 3-year periods before and after KAS were identified. Results: Highly sensitized patients (N = 1238 and 4687) received a deceased donor kidney transplant between January 1, 2011 and December 31, 2013 and between January 1, 2015 and December, 31, 2017. Racial disparity for highly sensitized patients improved, yet remained significant (P < 0.001), with Black patients comprising 40% and 41% of the highly sensitized candidates and 28% and 34% of the recipients pre- and post-KAS. While posttransplant death-censored graft failure for highly sensitized recipients was similar overall, post-KAS was associated with improved graft survival in the first year after transplant (HR 0.56, 95% CI 0.40-0.78). When compared to contemporaneous lowrisk recipients, both death-censored and all-cause graft failure were similar for highly sensitized recipients and was associated with increased risk for death-censored graft failure beyond the first year (HR 1.39, 95% CI 1.11-1.73). Conclusion: The allocation system led to an increase in transplantation in highly sensitized candidates without compromising outcomes. Although KAS has led to more balanced transplant rates between highly sensitized Black and White patients, racial inequalities persist.

Diagnosing the Recent Decrease in Utilization of Deceased Donor Kidneys.

The number of deceased donor kidney transplants has been increasing and is at a record high, yet nonuse of kidneys recovered for transplantation has risen to 25.8% following circular kidney allocation system based on 250-nautical-mile circles implemented on March 15, 2021 (KAS250). Using Scientific Registry of Transplant Recipients data, we studied all deceased donor kidneys recovered for transplant from March 15, 2019, to January 31, 2023. We calculated the association of multiple factors with kidney nonuse, including increasing recovery of kidneys from nonideal donors, delays in offer acceptance observed under KAS250, and impacts of COVID-19. In the 2 y before KAS250, the nonuse rate was 21.2%. Had this rate continued, 2334 more kidneys would have been transplanted through January 2023. We estimated that about 769 of these nonused kidneys (33%) were associated with offer acceptance delays under KAS250; about 994 of these nonused kidneys (43%) were associated with increased prevalence of nonideal donors: donation after circulatory death donors, older donors, and donors with elevated peak serum creatinine; and about 542 of these nonused kidneys (23%) were associated with an otherwise unexplained gradual upward trend in nonuse of recovered kidneys across the pre-KAS250 and KAS250 eras. The overall impact of COVID-19 on the nonuse rate was not significant. The rise in kidney nonuse rate was significantly associated with both increased recovery of nonideal donors, and with KAS250 allocation complexity and delays. Increasing recovery of kidneys from nonideal donors benefits patients because recovering more kidneys increases the number of kidneys available for transplant.

Allocation Rules and Age-Dependent Waiting Times for Kidney Transplantation.

Rigid age limits in the current allocation system for post-mortem donor kidneys in Germany may have problematic effects. The new German national transplantion registry enables data analysis with respect to this question. Using anonymized data from the German national transplantion registry, we extracted and evaluated information on the recipients and postmortem donors of kidneys that were allocated in Germany through Eurotransplant over the period 2006-2020. Data on 19 664 kidney transplantations in Germany from 2006 to 2020 were analyzed. The median waiting time for kidney transplantation was 5.8 years. Persons under age 18 waited a median of 1.7 years; persons aged 18 to 64, 7.0 years; and persons aged 65 and older, 3.8 years. Over the period of observation, postmortem kidneys were transplanted into 401 people of age 64 (2.0% of all organ recipients) and 1,393 people of age 65 (7.1% of all organ recipients). The difference in waiting times between allocation programs for persons under age 65 (ETKAS, "Eurotransplant Kidney Allocation System") and those aged 65 and older (ESP, "Eurotransplant Senior Program") increased over the period of observation, from 2.6 years in 2006-2010 to 4.1 years in 2017-2020. The rigid age limits in the current allocation rules for post-mortem kidney donations in Germany are prolonging the waiting times for transplants among patients aged 18 to 64. We think these rules need to be fundamentally reassessed.

Contemporary prevalence and practice patterns of out-of-sequence kidney allocation

Since 2021, the Organ Procurement and Transplantation Network has reported a nearly 10-fold rise in out-of-sequence (OOS) kidney allocation, generating concern and halting development of continuous distribution policies. We report contemporary (2022-2023) practice patterns in OOS allocation using Organ Procurement and Transplantation Network data. We examined in sequence vs OOS donors with multivariable logistic regression and skipped vs OOS-accepting recipients with conditional logistic regression. Nearly 20% of kidney placements were OOS, varying from 0% to 43% acsoss organ procurement organizations; the 5 highest OOS-organ procurement organizations accounted for 29% of all OOS. Of OOS kidneys, 33% were declined ≥100 times in the standard allocation sequence and 51% were declined by ≥10 centers before OOS allocation began; 4.5% were made without any in-sequence declines. Nearly, all OOS offers were open offers. OOS kidneys were more likely to be from female, Black, older, donation after cardiac death, hypertensive, diabetic, and elevated creatinine donors. Candidates receiving OOS kidneys were more likely female, Asian, and older than skipped candidates. Higher-volume centers and centers with more White, fewer Hispanic, and more educated waiting list patients underwent transplantation disproportionately with more OOS kidneys. These findings suggest that the current, highly variable, discretionary use of OOS might exacerbate disparities, yet the impact of OOS on organ utilization cannot be determined with data now collected.

Introduction of the donor centre virtual crossmatch in Eurotransplant.

On 24 January 2023, Eurotransplant has introduced the virtual crossmatch for kidney and pancreas allocation as a better alternative for the physical Complement Dependent Cytotoxicity (CDC) crossmatches at the donor centre, which were associated with a longer cold ischaemia time and false positive reactions. For the time being, the physical CDC crossmatch at the recipient centre will remain in place as the final histocompatibility check. While Eurotransplant is certainly not the first organ allocation organisation to introduce virtual crossmatching, several novel aspects have been introduced, such as calculation of the virtual panel reactive antibody (vPRA) on 11 loci at the second-field level in addition to the serological broad and split level, electronic HLA typing data transmission using Histoimmunogenetics Markup Language (HML) file format, and the actual virtual crossmatch based on ambiguous, second-field HLA typing of the donor on all 11 loci. This short communication will focus on these novel aspects of the virtual crossmatch in Eurotransplant.

Simultaneous Liver and Kidney Transplantation in Patients Aged 70 y and Older: Proceed With Caution.

The number of elderly patients aged 70 y and older with liver and kidney failure is increasing, mainly because of increasing prevalence of metabolic dysfunction-associated steatohepatitis. At present, limited data are available on the outcomes of elderly patients who fit the criteria for dual organ transplantation since the implementation of the simultaneous liver and kidney (SLK) allocation policy. We performed a retrospective analysis of the Organ Procurement and Transplantation Network database of adults aged 18 y and older undergoing SLK and kidney transplantation only from August 11, 2017, to December 31, 2022. We examined patient and graft survivals and compared the outcomes of the recipients aged 70 y and older undergoing SLK transplantation to those who received kidney transplant alone and kidney after liver transplant. During the study period, there has been a significant rise in the number of patients aged 70 y and older undergoing SLK transplantation, with 6 patients undergoing SLK transplantation in 2017 and 63 in 2021. Patients aged 70 y and older had significantly lower survival with 82.9% at 1 y and 66.5% at 3 y compared with 89.3% and 78.8% in the 50-69 y age group and 93.2% and 88.6% in the 18-49 y age group, respectively. Overall, kidney allograft survival was significantly lower in the 70 y and older group, with 80.9% at 1 y and 66.4% at 3 y compared with 91.1% and 75.5%, respectively, in those undergoing kidney transplant alone. There was no difference in kidney allograft survival in those undergoing SLK and kidney after liver transplantation. Although the outcomes are inferior in recipients of SLK transplant aged 70 y and older, chronologic age should not preclude them from undergoing transplantation. Kidney transplantation after liver transplantation could be considered to avoid futile transplants.

Equity in Kidney Allocation and Optimizing Utilization: Are These Goals Mutually Exclusive?

Equity in Kidney Allocation and Optimizing Utilization: Are These Goals Mutually Exclusive?

Effects of the March 2021 Allocation Policy Change on Key Deceased-donor Kidney Transplant Metrics.

A major change to deceased-donor kidney allocation in the United States, Kidney Allocation System 250 (KAS250), was implemented on March 15, 2021. Evaluating the consequences of this policy on critical system performance metrics is critical to determining its success. We performed a retrospective analysis of critical performance measures of the kidney transplant system by reviewing all organs procured during a 4-y period in the United States. To mitigate against possible effects of the COVID-19 pandemic, Scientific Registry of Transplant Recipients records were stratified into 2 pre- and 2 post-KAS250 eras: (1) 2019; (2) January 1, 2020-March14, 2021; (3) March 15, 2021-December 31, 2021; and (4) 2022. Between-era differences in rates of key metrics were analyzed using chi-square tests with pairwise z-tests. Multivariable logistic regression and analysis of variations methods were used to evaluate the effects of the policy on rural and urban centers. Over the period examined, among kidneys recovered for transplant, nonuse increased from 19.7% to 26.4% (all between-era P < 0.05) and among all Kidney Donor Profile Index strata. Cold ischemia times increased (P < 0.001); however, the distance between donor and recipient hospitals decreased (P < 0.05). Kidneys from small-metropolitan or nonmetropolitan hospitals were more likely to not be used over all times (P < 0.05). Implementation of KAS250 was associated with increased nonuse rates across all Kidney Donor Profile Index strata, increased cold ischemic times, and shorter distance traveled.

A novel allocation scheme for deceased donor kidneys to balance equity and utility.

Patients with sensitization and blood type O experience increased waiting times for deceased-donor kidney transplantation (DDKT). While allocation benefits are needed to resolve inequity in DDKT opportunity, whether DDKT has comparable outcomes in this disadvantaged population requires further study. This study assessed these outcomes and developed a new allocation system that balances equity and utility. Patients from national and hospital cohorts from two centers in Korea were categorized as B1 to B4 (according to panel reactive antibody [PRA] positivity and ABO blood type) and A1 to A4 (based on the maximal PRA% and blood type), respectively. Competing risk and Cox regression analyses were performed to assess the effects of PRA and blood type on graft failure and mortality, respectively. Based on DDKT opportunities and posttransplant outcomes, a new scoring system for kidney allocation was developed. The national and hospital cohorts included 3,311 and 819 patients, respectively, who underwent DDKT. Despite the disparities in DDKT opportunities, the graft failure rates and mortality did not differ among the different PRA and blood type groups. Furthermore, posttransplantation outcomes did not differ according to the categories with different DDKT opportunities. A new scoring system to provide additional points to disadvantaged populations was developed based on the hazard ratios for DDKT. A new allocation approach based on PRA and ABO blood types offers benefits to disadvantaged patients with fewer DDKT opportunities and could enhance equity without sacrificing utility in Korea, which has a long waiting time for DDKT.

#2425 A change in deceased donor allocation policy may provide gender equality in kidney transplantation

Abstract Background and Aims Overcoming gender disparity in access to kidney transplantation is a well-established universal challenge. The SRTR data showed a greater proportion of males than females for kidney transplant waitlists (61% vs 39%). Similarly, of 831 deceased donor kidney transplants (DDKT) conducted between 1997 and 2018 at IKDRC-ITS, 68% have been male and 32% female recipients while majority of donors in living donor kidney transplants (LDKT) were females. Prior to 2020, there duration on transplantation waitlist was the only criteria for deceased donor kidney allocation. In January 2020, SOTTO Gujarat was formed which implements a point system based deceased donor allocation policy including HLA mismatch, Panel Reactive Antibody, Donor Specific Antibody, age and duration on dialysis, amongst others. 2 additional points are allocated to female recipients in this allocation system. The aim is to study the impact of change in DDKT allocation policy on gender disparity. Method This is a retrospective, single-center, observational study. Number of male and female kidney transplant recipients was collected from the medical records held by the department of nephrology between January 2014 to December 2023. The data was categorized as before and after implementation of SOTTO Gujarat guidelines and analyzed. Results A total of 3182 kidney transplants were conducted at our centre over the study period, 2231 were LDKT while only 951 were DDKT. We found the percentage of female LDKT recipients to have remained disproportionately low as compared to male DDKT throughout the study period, while there was a gradually progressive increase in the percentage of female DDKT recipients with almost a doubling of female DDKT recipients from 27.57% in 2019 to 54.19% in 2023. This may be attributed to the compounding effect of allocating points to DSA, PRA, age of patient and gender as female patients tend to have higher PRA and DSA level after sensitization. Conclusion This study provides new insights into steps that can be taken to bridge the gender gap in DDKT. It shows that implementing a point based system for DDKT allocation policy with extra points for female recipients may increase the number of kidney transplants in them. Similar policy may be undertaken by other transplant centers as a bridge to achieve temporary solution till underlying factors leading to gender disparity are better understood and ways to overcome them are formed. Action should be taken to provide for equitable access to females at all stages, from diagnosis to treatment such as intensive and timely counselling. Policies for social empowerment of women must be formed including literacy, better maternal and child healthcare and financial independence. Raising awareness and education at a grassroot level must remain the key component to change public attitude regarding organ donation and ensure equitable access to transplantation for all.

Differences in Racial and Ethnic Disparities Between First and Repeat Kidney Transplantation.

Recent data suggest patients with graft failure had better access to repeat kidney transplantation (re-KT) than transplant-naive dialysis accessing first KT. This was postulated to be because of better familiarity with the transplant process and healthcare system; whether this advantage is equitably distributed is not known. We compared the magnitude of racial/ethnic disparities in access to re-KT versus first KT. Using United States Renal Data System, we identified 104 454 White, Black, and Hispanic patients with a history of graft failure from 1995 to 2018, and 2 357 753 transplant-naive dialysis patients. We used adjusted Cox regression to estimate disparities in access to first and re-KT and whether the magnitude of these disparities differed between first and re-KT using a Wald test. Black patients had inferior access to both waitlisting and receiving first KT and re-KT. However, the racial/ethnic disparities in waitlisting for (adjusted hazard ratio [aHR] = 0.77; 95% confidence interval [CI], 0.74-0.80) and receiving re-KT (aHR = 0.61; 95% CI, 0.58-0.64) was greater than the racial/ethnic disparities in first KT (waitlisting: aHR = 0.91; 95% CI, 0.90-0.93; Pinteraction = 0.001; KT: aHR = 0.68; 95% CI, 0.64-0.72; Pinteraction < 0.001). For Hispanic patients, ethnic disparities in waitlisting for re-KT (aHR = 0.83; 95% CI, 0.79-0.88) were greater than for first KT (aHR = 1.14; 95% CI, 1.11-1.16; Pinteraction < 0.001). However, the disparity in receiving re-KT (aHR = 0.76; 95% CI, 0.72-0.80) was similar to that for first KT (aHR = 0.73; 95% CI, 0.68-0.79; Pinteraction = 0.55). Inferences were similar when restricting the cohorts to the Kidney Allocation System era. Unlike White patients, Black and Hispanic patients with graft failure do not experience improved access to re-KT. This suggests that structural and systemic barriers likely persist for racialized patients accessing re-KT, and systemic changes are needed to achieve transplant equity.

Graft Survival of En Bloc Deceased Donor Kidneys Transplants Compared With Single Kidney Transplants.

The US Kidney Allocation System allocates en bloc deceased donor kidney grafts from donors <18 kg in sequence A along with single kidney transplants (SKTs) from kidney donor profile index (KDPI) top 20% donors. Although en bloc grafts outperform SKT grafts holding donor weight constant, it is unclear if en bloc grafts from the smallest pediatric donors perform the same as top 20% KDPI SKTs. Using the Scientific Registry of Transplant Recipients, we compared the donor characteristics and graft survival of en bloc grafts from the smallest donors (<8 kg) and from larger donors (≥8 kg) with SKTs by KDPI sequence for transplants performed in 2021. Larger donor en blocs had similar 1-y survival to sequence A SKTs estimated by the Kaplan-Meier method (96% versus 96%, P = 0.9), but the smallest donor en blocs had significantly shorter 1-y survival than those SKTs (80% versus 96%, P < 0.01). Using transplants from 2010 to 2012, the smallest donor en blocs had similar 10-y survival to sequence A SKTs (69% versus 64%, P = 0.3). These findings suggest that future updates of the Kidney Allocation System should include a score specific to pediatric donors to account for these differences in en bloc graft survival.

A2/A2B Deceased Donor Kidney Transplantation Using A2 Titers Improves Access to Kidney Transplantation: A Single-Center Study

Rationale and ObjectiveThe option for A2/A2B deceased donor kidney transplantation was integrated into the kidney allocation system in 2014 to improve access for B blood group waitlist candidates. Despite excellent reported outcomes, center uptake has remained low across the United States. Here we examined the effect of implementing an A2/A2B protocol using a cut off titer of ≤ 1:8 for IgG and 1:16 for IgM on blood group B kidney transplant recipients at a single center. Study DesignRetrospective observational study. Setting& Participants: Blood group B recipients of deceased donor kidney transplants at a single center from January 1, 2019 to December 2022. ExposureRecipients of deceased donor kidney transplants were analyzed based on donor blood type: A2/A2B vs. blood group compatible. Outcomes1 year patient survival, death censored allograft function, primary non-function, delayed graft function, allograft function as measured by serum creatinine and eGFR at 1 year, biopsy proven rejection, and need for plasmapheresis. Analytical ApproachComparison between the A2/A2B and compatible groups were performed using the Fisher test or the Chi-Square test for categorical variables and the nonparametric Wilcoxon Rank-Sum Test for continuous variables. ResultsA total of 104 blood type B patients received a deceased donor kidney transplant at our center during the study period, 49 (47.1%) of which received an A2/A2B transplant. Waiting time was lower in A2/A2B recipients compared to blood group compatible recipients (57.9 months vs. 74.7 months, p=0.01). A2/A2B recipients were more likely to receive a donor after cardiac death (24.5% vs 1.8%, p<0.05) and experience delayed graft function (65.3% vs. 41.8%). There were no observed differences in the average serum creatinine or eGFR at 1-month, 3-months, and 1-year post kidney transplantation, acute rejection, or primary non-function. LimitationsSingle center study. Small cohort size limiting outcome analysis. ConclusionsImplementation of an A2/A2B protocol increased transplant volumes of blood group B waitlisted patients by 83.6% while decreasing the waiting time for transplantation by 22.5% with similar transplant outcomes.