An algorithm for cadaver kidney allocation based on a multivariate analysis of factors impacting on cadaver kidney graft survival and function

Abstract The large imbalance between cadaver kidney supply and demand makes the implementation of equitable and effective organ allocation systems an urgent need. This has triggered a revision of the criteria used so far for cadaver kidney allocation within the North Italy Transplant program, not least in the light of the many changes that have occurred recently with respect to broader criteria for admission of patients to the waiting list, donor selection, tissue‐typing methods, organ preservation and immunosuppressive protocols. We based the critical revision of our cadaver kidney allocation algorithm on univariate and multivariate analysis of a number of immunological, clinical, social and administrative factors that impacted on the transplant outcome in 2,917 patients transplanted in the 12 transplant centers operating within our organization from 1 January 1990 to 30 September 1997. This analysis indicated that younger donor age, absence of pretransplant transfusions, patient dialysis center and level of HLA match showed statistically significant positive associations with graft survival. Younger donor age and male donor gender showed a statistically significant association with excellent graft function at 4 years. The results of this analysis were used to develop a new computer‐assisted version of our adult kidney allocation algorithm. It works in two steps (local pool first, then the entire waiting list) and four levels (0‐1 HLA MM, PRA +; 2 HLA MM, PRA +; 0‐1 MM, PRA‐; 2‐4 HLA MM, PRA‐); within each level, selection takes into account waiting time and age difference from donor age. The evaluation of 731 transplants allocated in 19 months with the new algorithm, as against 698 transplants allocated in the preceding 19 months according to the previous algorithm, showed a significantly higher proportion of recipients who had been on the waiting list for more than 3 years (33.2% versus 22.6%). The use of the new algorithm was also associated with a significantly increased number of transplanted alloimmunized patients (18.8% versus 9.2% with the previous algorithm) and recipients with 0‐1 HLA mismatches (22% versus 14.3%). Furthermore, the number of kidneys used locally has steadily increased. Differences in 6‐month graft survival and percentage of patients with excellent function at 6 months were not statistically significant in recipients transplanted with the new versus the previous algorithm. Survivals were 93.7% versus 91.8%. Percentages of patients with excellent renal function were 69.9% and 71.8%, respectively. These preliminary data suggest that the new algorithm improves HLA match and reduces the number of patients on the waiting list for 3 or more years without determining significant modifications of 6‐month graft survival and function. Moreover, it facilitates the achievement of a fair local balance between organs retrieved and transplanted, the compliance of operators with objective allocation rules and the documentation of the whole allocation process.     

A new allocation plan for renal transplantation

BACKGROUND: A novel plan of renal allograft allocation has been conducted by United Network for Organ Sharing Region 1 transplant centers since September 3, 1996, based upon HLA matching, time waiting, and population distance points. The objectives of this plan were to achieve a balance between increasing the opportunity of renal transplantation for those patients listed with long waiting times and promoting local organ donor availability. METHODS: A single list of candidates was formulated for each cadaver donor, assigning a maximum of 8 points for time waiting, a maximum of 8 points for population distance from the donor hospital, and HLA points based upon the degree of B/DR mismatch. Additional points were awarded to a cross-match-negative patient with a panel-reactive antibody of >80%, and to pediatric patients. RESULTS: The total number of kidneys transplanted to patients who had waited >3 years was 100 (46%), and to patients who had waited >2.5-3 years was 29 (13%). However, the total number of kidneys transplanted to patients with the maximum population distance points was only 72 (33%). Thus, although the plan achieved a favorable distribution of kidneys to patients with longer waiting times (nearly 60%), the other, equally important objective of promoting local donor availability was not initially accomplished. Moreover, minor HLA B/DR differences between the donor and the recipient (i.e., not phenotypically matched) were unexpectedly consequential in determining allocation. As a result of these observations, the following adjustments were made in the plan (as of December 3, 1997): a maximum of 10 points for population distance, a maximum of 8 points for time waiting (both by a linear correlation), and the retention of HLA points for 0 B/DR mismatch only. After these interval changes, the percentage of patients receiving a kidney with some population distance points increased from 85% to 96%. Conclusions. We have shown that a heterogeneous region of multiple transplant centers can devise (and modify) an innovative and balanced plan that provides an equitable system of allocation for an ever-increasing number of patients.     

HLA matching and the United Network for Organ Sharing Allocation System: impact of HLA matching on African-American recipients of cadaveric kidney transplants

BACKGROUND: A recent proposal supports the elimination of allocation points for human leukocyte antigen (HLA) mismatches (MM) in cadaveric kidney transplantation. The intent is to increase access for some racial groups that might be disadvantaged by the representation of race-specific HLA in a largely white donor pool. We report our experience from two transplant centers that serve a large African American (AA) patient population. METHODS: All cadaveric transplants into AA recipients from 1994 to 2000 (n=162) were included in a retrospective review. RESULTS: Superior graft survival was observed in AA recipients of 0 MM transplants. When induction therapy was used, the graft survival at 3 years for the human leukocyte antigen (HLA)-BDR MM grades given allocation points (0,1,2 MM) was 82% versus only 49% for BDR MM grades not given points (3,4 MM: =0.0022). CONCLUSIONS: Our collective experience demonstrates that AA patients having HLA-BDR MM grades given allocation points had better graft survival. Removing points for HLA from the national allocation system may result in significantly poorer outcome in AA kidney recipients.     

Expanding the donor pool to increase renal transplantation.

INTRODUCTION: The goal of the Eurotransplant renal allocation scheme is to provide every patient on the waiting list with a reasonably balanced opportunity for a donor offer. New initiatives were taken in order to maximize donor usage while maintaining a successful transplant outcome. METHODS: Two Eurotransplant projects were launched in order to accommodate changes in donor and recipient profiles. A re-addressing of the non-heart-beating donor pool was undertaken and an allocation scheme in which organs from donors aged >65 are allocated to recipients aged >65 [the Eurotransplant Senior Programme (ESP)] was introduced. RESULTS: Especially in The Netherlands, an enormous increase in the number of non-heart-beating donor kidneys has been observed, however with a pace-keeping reduction in heart-beating donors. The organization-wide implementation of the ESP has been successful. The 3 year graft survival rates for these age-matched transplants were as good as the human leukocyte antigen (HLA)-matched transplants (64 vs 67%) (P = 0.4). CONCLUSION: Within the framework of sound research, the utmost flexibility and creativity is needed to keep or even increase the number of renal transplants when faced with a quantitatively stagnating but qualitatively deteriorating donor pool. Both the non-heart-beating donor protocol and the ESP have proven to be quite successful in achieving this goal without compromising the outcome for the individual end-stage renal disease patient.     

Consequences of the Implementation of the Model for End-stage Liver Disease System for Liver Allocation in Brazil

Background

In July 2006, the system for liver allocation in Brazil started to rely on the Model for End-stage Liver Disease (MELD) scale, replacing the previous chronological criteria. Under the new system, the score for listing pediatric patients is obtained by multiplication of the calculated PELD score by 3. The current criteria also features extra points for diseases such as hepatocellular carcinoma (HCC). This study sought to analyze the consequences of implementation of the MELD system on waiting list mortality, posttransplant survival rates and characteristics of the transplanted patients.

Methods

We retrospectively studied data from the State Health Secretariat of São Paulo, regarding all patients registered on the waiting list for liver transplantation in the State of São Paulo, in two periods: July 2005 to July 2006 (pre-MELD era) and July 2006 to July 2010 (MELD era). Patient survival rates calculated using the Kaplan-Meier method were compared by the log-rank test. P values <.05 were considered statistically relevant.

Results

After implementation of the MELD, waiting list registrations decreased by 39.8%; the percentage of transplants in HCC recipients increased from 2.4% to 23.7%; pediatric transplants increased from 6.5% to 9.3%; deaths on the list fell from 599 in the pre-MELD era to 359 in the last year analyzed; recipients with higher MELD displayed significantly lower posttransplant survival rates; HCC patients, better survival after transplantation (P = .002); No difference was observed comparing survival rates between pre-MELD and MELD eras (P = 474) or between adults and children (P = .867).

Conclusion

Under the MELD system for liver allocation in Brazil, there was a reduction in waiting list mortality and an increased number of transplantations in pediatric and HCC recipients. Survival rates of patients with higher MELD score were inferior. However, this result was offset by the greater survival in HCC recipients, with no difference in patient survival rates between the pre-MELD and MELD eras.     

OPTN/SRTR 2019 Annual Data Report: Kidney

Despite the ongoing severe shortage of available kidney grafts relative to candidates in need, data from 2019 reveal some promising trends. After remaining relatively stagnant for many years, the number of kidney transplants has increased each year since 2015, reaching the highest annual count to date of 24,273 in 2019. The number of patients waiting for a kidney transplant in the United States was relatively stable, despite an increase in the number of new candidates added in 2019 and a decrease in patients removed from the waiting list owing to death or deteriorating medical condition. However, these encouraging trends are tempered by ongoing challenges. Nationwide, only a quarter of waitlisted patients receive a deceased-donor kidney transplant within 5 years, and this proportion varies dramatically by donation service area, from 15.5% to 67.8%. The non-utilization (discard) rate of recovered organs remains at 20.1%, despite adramatic decline in the discard of organs from hepatitis C-positive donors. Non-utilization rates remain particularly high for Kidney Donor Profile Index ≥85% kidneys and kidneys from which a biopsy specimen was obtained. While the number of living-donor transplants increased again in 2019, only a small proportion of the waiting list receives living-donor transplants each year, and racial disparities in living-donor transplant access persist. As both graft and patient survival continue to improve incrementally, the total number of living kidney transplant recipients with a functioning graft is anticipated to exceed 250,000 in the next 1-2 years. Over the past decade, the total number of pediatric kidney transplants performed has remained stable. Despite numerous efforts, living donor kidney transplant remains low among pediatric recipients with continued racial disparities among recipients. Congenital anomalies of the kidney and urinary tract remain the leading cause of kidney disease. While most deceased donor recipients receive a kidney from a donor with KDPI less than 35%, the majority of pediatric recipients had four or more HLA mismatches. Graft survival continues to improve with superior outcomes for living donor recipients.     

Recipient race does not influence waiting time for a cadaveric renal transplant--one organ procurement organization's experience

There was no statistical significance to the differences in waiting time for cadaveric renal transplant by race. Whether for first transplant or second or greater, any differences in waiting time could not be accounted for by the recipient's race. CAUC made up 58% of the waiting list, 65% of the recipients, and 87% of the donors. The corresponding numbers for AA are: 38%, 29%, and 10%, respectively. More regional serum-sharing trays may be needed in order to expose recipients with high PRA to as many donors as possible in order to lessen their waiting time. It should be noted that fewer HLA mismatches occurred when donor and recipient race were identical. In light of this data, more study is needed to determine the relationship between donor and recipient race, corresponding HLA mismatches, and graft survival. If antigen-matching is found to increase graft survival, then an increase in minority donations will be required. Until that time, under the current allocation system and with the predominance of Caucasian donors, it is likely that Afro-Americans will continue to receive kidneys that have more HLA antigen mismatches than if Afro-Americans donated in numbers equivalent to their percentage of the waiting list.     

Current Kidney Allocation Rules and Their Impact on a Pediatric Transplant Center

In 2005, kidney allocation rules in the United States were updated to enhance access to kidneys from young adult deceased donors (DDs) for pediatric recipients. We studied how this rule change affected transplant activity at our pediatric center. We retrospectively compared kidney transplant activity at our center since the rule change (until December 31, 2007) to before the change (n = 36 each), focusing on those recipients directly affected by it, that is, younger than 18 years. There were no significant differences in recipients' age, gender or ethnicity before versus after the rule change. Percentages of preemptive transplants and retransplants were similar in both groups, as was the percentage of sensitized patients. There was a significant decrease in overall, but not DD, mean donor age. Mean wait time for DD kidneys decreased for pediatric recipients. Increases were found in percentage of DD transplants and in mean HLA mismatches after the rule change. Patient and short-term graft survival were not significantly different. These data suggest that the allocation rule change was not only followed by improvement in overall access to kidney transplantation for children, but also by decreases in living donor transplants and HLA matching. Larger studies are needed to evaluate the long-term impact of the change.     

A novel united network for organ sharing region kidney allocation plan improves transplant access for minority candidates

BACKGROUND: We report the consequences of a novel kidney allocation system on access of non-Caucasians (NC) to kidney transplantation. This new plan has provided a balance of allocation determinants between time waiting, HLA match, and geography (population density between donor and recipient center). METHODS: Three sequential systems of regional allocation were analyzed: period I (September 1994 to September 1996), period II (September 1996 to November 1997), and period III (December 1997 to March 1 1999). Periods II and III are reflective of the new allocation plan. RESULTS: During periods II and III, the NC rate of kidney transplantation increased closer to the NC proportion on the wait list, comparatively exceeding the national UNOS data. There was no statistical difference in regional mean wait time between Caucasian and NC. Improvements in access to transplantation for NCs between period I and periods II and III appear to be related to changes in geographic allocation weight from local unit to population density points, to the inclusion of the entire region in the plan, and to the deletion of intermediate degrees of B/DR mismatching in the revised plan. Despite the increased proportion of NCs on the wait list from period I to period III, the percentage difference between the proportion of NCs waiting on the list and the proportion NCs receiving a transplant fell from 7.8% to 4.9%. CONCLUSIONS: These data demonstrate that this new allocation plan was associated with improved access of minority candidates to transplantation. The broadening of geographic allocation and the alteration of HLA points appear to permit a more favorable opportunity for renal transplantation to NC candidates. selection, compared to the UNOS formula. In this report, we analyze the consequences of the Region 1 allocation system on the access of non-Caucasian (NC) candidates to cadaver donor kidney transplantation.     

Allocation of cadaver donor kidneys in Australia

The national allocation of kidneys in Australia is based on a combination of human leukocyte antigen (HLA) matching and equity factors designed to make transplantation accessible to as many patients as possible. A points system has been designed that deducts points for HLA mismatches but adds points for factors such as levels of HLA sensitization, waiting time on dialysis, and a loading for pediatric patients. Kidneys that do not reach the level of matching required for national allocation are transplanted in the donor state using both matching and waiting time criteria, which caters to minority groups with rare HLA types.     

For the many: permitting deceased donor kidney transplantation across low‐titre blood group antibodies can reduce wait times for blood group B recipients,and improve the overall number of 000MM transplants ‐ a multicentre observational cohort study

Blood group O or B recipients wait longer for a kidney transplant. We studied the distribution of anti‐ABO blood group antibody titres in patients awaiting a kidney transplant, and modelled the effect of altering the UK National Kidney Allocation Scheme to allow for patients with ‘LOW’ titres (≤1:8, ≤3 dilutions) to receive a deceased donor ABOi (ddABOi) transplant. In a prospective study of 239 adult patients on the waiting list for a transplant in 2 UK centres, ABO‐antibody titres (anti‐A and anti‐B) were measured. Based on the proportions of ‘LOW’ anti‐A or anti‐B antibodies, four simulations were performed to model the current allocation rules compared with variations allowing ddABOi allocation under various conditions of blood group, HLA matching, and waiting time. The simulations permitting ddABOi resulted in more blood group B recipients being transplanted, with median waiting time reduced for this group of recipients, and more equitable waiting times across blood groups. Additionally, permitting ddABOi resulted in greater numbers of 000MM allocations overall in compatible transplants under modelled conditions. Changing allocation in the UK to permit ddABOi in patients with ‘LOW’ titres would not change the total number of transplants, but redistributes allocation more equitably amongst blood groups, altering waiting times accordingly.     

Liver and Intestine Transplantation in the United States, 1997–2006

Liver transplantation in 2006 generally resembled previous years, with fewer candidates waiting for deceased donor liver transplants (DDLT), continuing a trend initiated with the implementation of the model for end-stage liver disease (MELD). Candidate age distribution continued to skew toward older ages with fewer children listed in 2006 than in any prior year. Total transplants increased due to more DDLT with slightly fewer living donor liver transplants (LDLT). Waiting list deaths and time to transplant continued to improve. In 2006, there also were fewer DDLT for patients with MELD <15, fewer pediatric Status 1A/B transplants and more transplants from donation after cardiac death (DCD) donors. Adjusted patient and graft survival rates were similar for LDLT and DDLT. This article also contains in-depth analyses of transplantation for hepatocellular carcinoma (HCC). Recipients with HCC had lower adjusted 3-year posttransplant survival than recipients without HCC. HCC recipients who received pretransplant ablative treatments had superior adjusted 3-year posttransplant survival compared to HCC recipients who did not. Intestinal transplantation continued to slowly increase with the largest number of candidates on the waiting list since 1997. Survival rates have increased over time. Small children waiting for intestine grafts continue to have the highest waiting list mortality.     

Changes in Pediatric Renal Transplantation After Implementation of the Revised Deceased Donor Kidney Allocation Policy

In October 2005, the United Network for Organ Sharing (UNOS) implemented a revised allocation policy requiring that renal allografts from young deceased donors (DDs) (<35 years old) be offered preferentially to pediatric patients (<18 years old). In this study, we compare the pre- and postpolicy quarterly pediatric transplant statistics from 2000 to 2008. The mean number of pediatric renal transplants with young DDs increased after policy implementation from 62.8 to 133 per quarter (p < 0.001), reflecting a change in the proportion of all transplants from young DDs during the study period from 0.33 to 0.63 (p < 0.001). The mean number of pediatric renal transplants from old DDs (≥35 years old) decreased from 22.4 to 2.6 per quarter (p < 0.001). The proportion of all pediatric renal transplants from living donors decreased from 0.55 to 0.35 (p < 0.001). The proportion from young DDs with five or six mismatched human leukocyte antigen (HLA) loci increased from 0.16 to 0.36 (p < 0.001) while those with 0 to 4 HLA mismatches increased from 0.18 to 0.27 (p < 0.001). Revision of UNOS policy has increased the number of pediatric renal transplants with allografts from young DDs, while increasing HLA-mismatched allografts and decreasing the number from living donors.     

Transplanting Kidneys Without Points for HLA‐B Matching: Consequences of the Policy Change

In 2003, the US kidney allocation system was changed to eliminate priority for HLA‐B similarity. We report outcomes from before and after this change using data from the Scientific Registry of Transplant Recipients (SRTR). Analyses were based on 108 701 solitary deceased donor kidney recipients during the 6 years before and after the policy change. Racial/ethnic distributions of recipients in the two periods were compared (chi‐square); graft failures were analyzed using Cox models. In the 6 years before and after the policy change, the overall number of deceased donor transplants rose 23%, with a larger increase for minorities (40%) and a smaller increase for non‐Hispanic whites (whites) (8%). The increase in the proportion of transplants for non‐whites versus whites was highly significant (p < 0.0001). Two‐year graft survival improved for all racial/ethnic groups after implementation of this new policy. Findings confirmed prior SRTR predictions. Following elimination of allocation priority for HLA‐B similarity, the deficit in transplantation rates among minorities compared with that for whites was reduced but not eliminated; furthermore, there was no adverse effect on graft survival.     

Efficiency is a legitimate consideration in equitable distribution of cadaveric transplants: development of an efficiency-equality model of equity

It is proposed that equity is a trade-off, or compromise, between equality and efficiency. The kidney transplant allocation algorithm currently used in the United Kingdom (NAT) was tested in the efficiency-equity model. In an exercise of 2000 past UK donors and a dynamic waiting list of 5000 potential recipients, 4000 transplants were allocated according either by NAT, by equal allocation (EQ) (a lottery), or by efficiency (EF). Diabetic recipients received 7.4% of transplants in NAT, 8.6% in EQ, and 0% in EF; paediatric recipients received 6.8% in NAT, 0.6% in EQ, and 0.7% in EF model. For HLA matching, there were 77.9% favourable or 000 matches in NAT, 3.0% in EQ, and 53.1% in EF. Predicted survival showed better outcomes in EF versus NAT (P < .0001) and in NAT versus EQ (P = .05). The NAT allocation system favours paediatric recipients and does not deny diabetics the chance of a transplant, broadly in line with published public and professional opinions. The NAT scheme achieves better HLA matching than the EF model, and this suggests that the rationale for allocation based primarily on HLA matching could be reexamined.     

The impact of HLA frequency differences in races on the access to optimally HLA-matched cadaver renal transplants. The Medical Advisory Committee.

We examined the donor/recipient HLA match of 448 consecutive cadaver renal transplants to determine if donor race had an impact on the quality of HLA match that was achieved. Eighty (17.9%) kidneys from black donors and 368 (82.1%) from nonblack donors (87.8% caucasians) were distributed to the blood type compatible and crossmatch negative recipients on the basis of a local variance of the United Network for Organ Sharing (UNOS) point system. There were 278 (62%) nonblack and 170 (38%) black recipients, numbers close to those of nonblacks and blacks on the waiting list (59% and 41%, respectively). Kidneys from nonblack donors represented 86% (240/278) of transplants for nonblack and 75% (128/170) of transplants for black recipients. The best matches, i.e., zero-A,B,DR, zero-A,B, zero-B,DR, and 1-A,B,DR mismatches, for nonblack recipients were solely derived from the nonblack donors, and the few well-matched kidneys from black donors were distributed to black recipients. Black recipients with zero mismatches were few (3, 2%) compared with nonblacks (21, 8%). Kidneys received by black recipients were more likely to be poorly matched (5-6 mismatches) if coming from nonblack donors (57/128, 44%) than black donors (11/42, 26%), P = 0.035. It was also observed from HLA frequency comparisons that well-matched kidneys from nonblack donors were rarely distributed to black patients with HLA phenotypes unique to or more common in blacks who represented a sizeable portion of blacks on the waiting list. We conclude that better donor/recipient HLA matches are achieved when both donors and recipients are of the same race. Thus a larger number of black donors are needed to improve the quality of HLA matching for potential black kidney transplant recipients.     

HLA-DR基因相容对肾移植长期存活的影响

目的 研究人类白细胞Ⅱ类抗原（ＨＬＡ－ＤＲ）基因相容对肾移植长期存活的影响。方法 采用基因分型技术,回顾性分析５１８例首次肾移植ＨＬＡ－ＤＲ基因相容性情况。结果 单个移植中心达到基因水平ＤＲ相配的受者超过１０Ａ％,半数以上可达１个ＤＲ相配。ＨＬＡ－ＤＲ相容的受者急性排斥反应显著减少,早期肾功能恢复顺利,１－５年人存活率提高１０％－２１．７％,肾存活率提高１７％－３７．７％,差异有显著性。     

Developments in pediatric liver transplantation since implementation of the new allocation rules in Eurotransplant

Liver allocation in the Eurotransplant (ET) region has changed from a waiting time to an urgency‐based system using the model of end‐stage liver disease (MELD) score in 2006. To allow timely transplantation, pediatric recipients are allocated by an assigned pediatric MELD independent of severity of illness. Consequences for children listed at our center were evaluated by retrospective analysis of all primary pediatric liver transplantation (LTX) from deceased donors between 2002 and 2010 (110 LTX before/50 LTX after new allocation). Of 50 children transplanted in the MELD era, 17 (34%) underwent LTX with a high‐urgent status that was real in five patients (median lab MELD 22, waiting time five d) and assigned in 12 patients (lab MELD 7, waiting time 35 d). Thirty‐three children received a liver by their assigned pediatric MELD (lab MELD 15, waiting time 255 d). Waiting time in the two periods was similar, whereas the wait‐list mortality decreased (from about four children/yr to about one child/yr). One‐ and three‐yr patient survival showed no significant difference (94.5/97.7%; p = 0.385) as did one‐ and three‐yr graft survival (80.7/75.2%; and 86.5/82%; p = 0.436 before/after). Introduction of a MELD‐based allocation system in ET with assignment of a granted score for pediatric recipients has led to a clear priorization of children resulting in a low wait‐list mortality and good clinical outcome.     

Does cadaveric donor renal transplantation ever provide better outcomes than live-donor renal transplantation?

BACKGROUND: Live donor renal transplantation (LRT) now comprises more than 40% of all kidney transplants performed in the United States. Many patients on the cadaveric waiting list have a prospective live kidney donor. This study determines whether cadaveric donor renal transplantation (CRT) can demonstrate better outcomes than LRT. METHODS: From the United States Renal Data System registry, 31,909 adult recipients of a first-time kidney transplant from 1995 to 1998 were analyzed. Recipients were followed until December 31, 2000. RESULTS: CRT, more human leukocyte antigen (HLA) mismatches, increased donor age, cold ischemia time greater than 24 hr, African American recipient, and a history of diabetic nephropathy all increased the risk of graft failure, return to dialysis, and death. Nevertheless, in specific circumstances, CRT could provide better outcomes than LRT. For example, in recipients aged 18 to 59 years with a hypothetical live kidney donor aged 50 years and four HLA mismatches, the relative risk of graft loss with LRT is comparable or increased compared with CRT if the cadaveric kidney donor is much younger or with fewer HLA mismatches. On the other hand, for recipients aged 60 years or older, CRT never provides better outcomes than LRT. All analyses were adjusted for recipient race, gender, and history of diabetic nephropathy. There were no significant interactions among donor type, HLA mismatches, donor age, and cold ischemia time. CONCLUSIONS: The elderly recipient with an imminent LRT should never be offered CRT. A combination of recipient and donor factors can make CRT preferable to LRT in younger patients.     

Calculated PRA: Initial Results Show Benefits for Sensitized Patients and a Reduction in Positive Crossmatches

The calculated panel reactive antibody (CPRA), which is based upon unacceptable HLA antigens listed on the waitlist form for renal transplant candidates, replaced PRA as the measure of sensitization among US renal transplant candidates on October 1, 2009. An analysis of the impact of this change 6 months after its implementation shows an 83% reduction in the number of kidney offers declined nationwide because of a positive crossmatch. The increasing acceptance and utilization of unacceptable HLA antigens to avoid offers of predictably crossmatch‐positive donor kidneys has increased the efficiency of kidney allocation, resulting in a significant increase in the percentage of transplants to broadly sensitized (80+% PRA/CPRA) patients from 7.3% during the period 07/01/2001–6/30/2002 to 15.8% of transplants between 10/1/09–3/31/10. The transplant rates per 1000 active patient‐years on the waitlist also increased significantly for broadly sensitized patients after October 1, 2009. These preliminary results suggest that ‘virtual’ positive crossmatch prediction based on contemporary tools for identifying antibodies directed against HLA antigens is effective, increases allocation efficiency and improves access to transplants for sensitized patients awaiting kidney transplantation.