Rescue Allocation Modes in Eurotransplant Kidney Transplantation: Recipient Oriented Extended Allocation Versus Competitive Rescue Allocation-A Retrospective Multicenter Outcome Analysis

BACKGROUND

Whenever the kidney standard allocation (SA) algorithms according to the Eurotransplant (ET) Kidney Allocation System or the Eurotransplant Senior Program fail, rescue allocation (RA) is initiated. There are 2 procedurally different modes of RA: recipient oriented extended allocation (REAL) and competitive rescue allocation (CRA). The objective of this study was to evaluate the association of patient survival and graft failure with RA mode and whether or not it varied across the different ET countries.

METHODS

The ET database was retrospectively analyzed for donor and recipient clinical and demographic characteristics in association with graft outcomes of deceased donor renal transplantation (DDRT) across all ET countries and centers from 2014 to 2021 using Cox proportional hazards methods.

RESULTS

Seventeen thousand six hundred seventy-nine renal transplantations were included (SA 15 658 [89%], REAL 860 [4.9%], and CRA 1161 [6.6%]). In CRA, donors were older, cold ischemia times were longer, and HLA matches were worse in comparison with REAL and especially SA. Multivariable analyses showed comparable graft and recipient survival between SA and REAL; however, CRA was associated with shorter graft survival. Germany performed 76% of all DDRTs after REAL and CRA and the latter mode reduced waiting times by up to 2.9 y.

CONCLUSIONS

REAL and CRA are used differently in the ET countries according to national donor rates. Both RA schemes optimize graft utilization, lead to acceptable outcomes, and help to stabilize national DDRT programs, especially in Germany.

Design, cohort profile and comparison of the KTD-Innov study: a prospective multidimensional biomarker validation study in kidney allograft rejection

There is an unmet need for robust and clinically validated biomarkers of kidney allograft rejection. Here we present the KTD-Innov study (ClinicalTrials.gov, NCT03582436), an unselected deeply phenotyped cohort of kidney transplant recipients with a holistic approach to validate the clinical utility of precision diagnostic biomarkers. In 2018-2019, we prospectively enrolled consecutive adult patients who received a kidney allograft at seven French centers and followed them for a year. We performed multimodal phenotyping at follow-up visits, by collecting clinical, biological, immunological, and histological parameters, and analyzing a panel of 147 blood, urinary and kidney tissue biomarkers. The primary outcome was allograft rejection, assessed at each visit according to the international Banff 2019 classification. We evaluated the representativeness of participants by comparing them with patients from French, European, and American transplant programs transplanted during the same period. A total of 733 kidney transplant recipients (64.1% male and 35.9% female) were included during the study. The median follow-up after transplantation was 12.3 months (interquartile range, 11.9-13.1 months). The cumulative incidence of rejection was 9.7% at one year post-transplant. We developed a distributed and secured data repository in compliance with the general data protection regulation. We established a multimodal biomarker biobank of 16,736 samples, including 9331 blood, 4425 urinary and 2980 kidney tissue samples, managed and secured in a collaborative network involving 7 clinical centers, 4 analytical platforms and 2 industrial partners. Patients' characteristics, immune profiles and treatments closely resembled those of 41,238 French, European and American kidney transplant recipients. The KTD-Innov study is a unique holistic and multidimensional biomarker validation cohort of kidney transplant recipients representative of the real-world transplant population. Future findings from this cohort are likely to be robust and generalizable.

Time-Varying Determinants of Graft Failure in Pediatric Kidney Transplantation in Europe

BACKGROUND

Little is known about the time-varying determinants of kidney graft failure in children.

METHODS

We performed a retrospective study of primary pediatric kidney transplant recipients (younger than 18 years) from the Eurotransplant registry (1990-2020). Piece-wise exponential additive mixed models were applied to analyze time-varying recipient, donor, and transplant risk factors. Primary outcome was death-censored graft failure.

RESULTS

We report on 4528 kidney transplantations, of which 68% with deceased and 32% with living donor. One thousand six hundred and thirty-eight recipients experienced graft failure, and 168 died with a functioning graft. Between 2011 and 2020, the 5-year graft failure risk was 10% for deceased donor and 4% for living donor kidney transplant recipients. Risk of graft failure decreased five-fold from 1990 to 2020. The association between living donor transplantation and the lower risk of graft failure was strongest in the first month post-transplant (adjusted hazard ratio, 0.58; 95% confidence interval, 0.46 to 0.73) and remained statistically significant until 12 years post-transplant. Risk factors for graft failure in the first 2 years were deceased donor younger than 12 years or older than 46 years, potentially recurrent kidney disease, and panel-reactive antibody >0%. Other determinants of graft failure included dialysis before transplantation (until 5 years post-transplant), human leukocyte antigen mismatch 2-4 (0-15 years post-transplant), human leukocyte antigen mismatch 5-6 (2-12 years post-transplant), and hemodialysis (8-14 years post-transplant). Recipients older than 11 years at transplantation had a higher risk of graft failure 1-8 years post-transplant compared with other age groups, whereas young recipients had a lower risk throughout follow-up. Analysis of the combined effect of post-transplant time and recipient age showed a higher rate of graft failure during the first 5 years post-transplant in adolescents compared with young transplant recipients. In contrast to deceased donor younger than 12 years, deceased donor older than 46 years was consistently associated with a higher graft failure risk.

CONCLUSIONS

We report a long-term inverse association between living donor kidney transplantation and the risk of graft failure. The determinants of graft failure varied with time. There was a significant cumulative effect of adolescence and time post-transplant. The ideal donor age window was dependent on time post-transplant.

Revising model for end-stage liver disease from calendar-time cross-sections with correction for selection bias

BACKGROUND

Eurotransplant liver transplant candidates are prioritized by Model for End-stage Liver Disease (MELD), a 90-day waitlist survival risk score based on the INR, creatinine and bilirubin. Several studies revised the original MELD score, UNOS-MELD, with transplant candidate data by modelling 90-day waitlist mortality from waitlist registration, censoring patients at delisting or transplantation. This approach ignores biomarkers reported after registration, and ignores informative censoring by transplantation and delisting.

METHODS

We study how MELD revision is affected by revision from calendar-time cross-sections and correction for informative censoring with inverse probability censoring weighting (IPCW). For this, we revised UNOS-MELD on patients with chronic liver cirrhosis on the Eurotransplant waitlist between 2007 and 2019 (n = 13,274) with Cox models with as endpoints 90-day survival (a) from registration and (b) from weekly drawn calendar-time cross-sections. We refer to the revised score from cross-section with IPCW as DynReMELD, and compare DynReMELD to UNOS-MELD and ReMELD, a prior revision of UNOS-MELD for Eurotransplant, in geographical validation.

RESULTS

Revising MELD from calendar-time cross-sections leads to significantly different MELD coefficients. IPCW increases estimates of absolute 90-day waitlist mortality risks by approximately 10 percentage points. DynReMELD has improved discrimination over UNOS-MELD (delta c-index: 0.0040, p < 0.001) and ReMELD (delta c-index: 0.0015, p < 0.01), with differences comparable in magnitude to the addition of an extra biomarker to MELD (delta c-index: ± 0.0030).

CONCLUSION

Correcting for selection bias by transplantation/delisting does not improve discrimination of revised MELD scores, but substantially increases estimated absolute 90-day mortality risks. Revision from cross-section uses waitlist data more efficiently, and improves discrimination compared to revision of MELD exclusively based on information available at listing.

Liver transplantation for HCC in cirrhosis: Are Milan criteria outdated?

In Germany, organ allocation is based on the MELD-system and lab-MELD is usually low in patients with hepatocellular carcinoma (HCC) in cirrhosis. Higher medical urgency can be achieved by standard exception for HCC (SE-HCC), if Milan criteria (MC) are met. Noteworthy, UNOS T2 reflects MC, but excludes singular lesions < 2 cm. Thus, SE-HCC is awarded to patients with one lesion between 2 and 5 cm or 2 to 3 lesions between 1 and 3 cm. These criteria are static and do not reflect biological properties of HCC.We present a retrospective cohort of 111 patients, who underwent liver transplantation at UKSH, Campus Kiel between 2007 and 2017. No difference was found in overall survival for patient cohorts using Milan, UCSF, up-to-seven, and French-AFP criteria. However, there was a significantly reduced survival, if microvascular invasion was detected in the explanted organ and in patients with HCC-recurrence. The exclusive use of static selection criteria including MC appear to limit the access to liver transplantation.

Immunized Patients Face Reduced Access to Transplantation in the Eurotransplant Kidney Allocation System

BACKGROUND

The presence of donor-specific HLA antibodies before transplantation is associated with poor transplantation outcomes. Unacceptable antigens can be assigned for Eurotransplant kidney transplant candidates to prevent kidney offers against which the candidate has developed clinically relevant HLA antibodies. This retrospective cohort study aimed to assess to what degree unacceptable antigens affect access to transplantation in the Eurotransplant Kidney Allocation System (ETKAS).

METHODS

Candidates who underwent kidney-only transplantation between 2016 and 2020 were included (n = 19 240). Cox regression was used to quantify the relationship between the relative transplantation rate and virtual panel-reactive antibodies (vPRAs), which is the percentage of the donor pool with unacceptable antigens. Models used accrued dialysis time as the timescale; were stratified by country and blood group of patient and were adjusted for nontransplantable status, patient age, sex, history of kidney transplantations, and prevalence of 0 HLA-DR-mismatched donors.

RESULTS

Transplantation rates were 23% lower for vPRA 0.1% to 50%, 51% lower for vPRA 75% to 85%, and decreased rapidly for vPRA of >85%. Prior studies showed significantly lower ETKAS transplantation rates only for highly sensitized patients (vPRA of >85%). The inverse relationship between transplantation rate and vPRA is independent of Eurotransplant country, listing time, and 0 HLA-DR-mismatched donor availability. Results were similar when quantifying the relationship between vPRA and attainment of a sufficiently high rank for an ETKAS offer, suggesting lower transplantation rates for immunized patients are due to current ETKAS allocation.

CONCLUSIONS

Immunized patients face lower transplantation rates across Eurotransplant. The current ETKAS allocation mechanism inadequately compensates immunized patients for reduced access to transplantation.

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.

Retransplanting a previously transplanted kidney: A safe strategy in times of organ shortage?

BACKGROUND

The shortage of organs for transplantation remains a global problem. The retransplantation of a previously transplanted kidney might be a possibility to expand the pool of donors. We provide our experience with the successful reuse of transplanted kidneys in the Eurotransplant region.

METHODS

A query in the Eurotransplant database was performed between January 1, 1995 and December 31, 2015, to find kidney donors who themselves had previously received a kidney graft.

RESULTS

Nine out of a total of 68,554 allocated kidneys had previously been transplanted. Four of these kidneys were transplanted once again. The mean interval between the first transplant and retransplantation was 1689±1682 days (SD; range 55-5,333 days). At the time of the first transplantation the mean serum creatinine of the donors was 1.0 mg/dl (.6-1.3 mg/dl) and at the second transplantation 1.4 mg/dl (.8-1.5 mg/dl). The mean graft survival in the first recipient was 50 months (2-110 months) and in the second recipient 111 months (40-215 months).

CONCLUSION

Transplantation of a previously transplanted kidney may successfully be performed with well-preserved graft function and long-term graft survival, even if the first transplantation was performed a long time ago. Such organs should be considered even for younger recipients in carefully selected cases.

Development of the Eurotransplant Discard Risk Index to Predict Acceptance of Livers for Transplantation: A Retrospective Database Analysis

OBJECTIVES

The utilization of liver allografts could be optimized if nonacceptance is predicted. This study aimed to evaluate the prognostic ability of an updated Discard Risk Index in Eurotransplant.

MATERIALS AND METHODS

Potential deceased donors from January 2010 to December 2015 who had been reported to Eurotransplant were included in our analyses. Liver utilization was defined by transplant status as the primary outcome to evaluate the performance of the Eurotransplant-developed Discard Risk Index.

RESULTS

Of 11670 potential livers, 9565 (81%) were actually transplanted. Donor sex, age, history of diabetes, drug abuse, use of vasopressors, body mass index category, serum sodium, cause of death, donor type, and levels of C-reactive protein, bilirubin, aspartate and alanine aminotransferases, international normalized ratio, and gamma-glutamyltranspeptidase were associated with discard and combined in the Eurotransplant-developed Discard Risk Index. Correlation between the two Discard Risk Indexes was high (r = 0.86), and both achieved high C statistics of 0.72 and 0.75 (P < .001), respectively. Despite strong calibration, discard rates of 0.8% for overall donors and 6% of donors after circulatory death could be predicted with 80% accuracy.

CONCLUSIONS

The Eurotransplant-developed Discard Risk Index showed a high prognostic ability to predict liver utilization in a European setting. The model could therefore be valuable for identifying livers at high risk of not being transplanted in an early stage. These organs might profit the most from modified allocation strategies or advanced preservation techniques.

Development and validation of a dynamic survival prediction model for patients with acute-on-chronic liver failure

Background & Aims

Acute-on-chronic liver failure (ACLF) is usually associated with a precipitating event and results in the failure of other organ systems and high short-term mortality. Current prediction models fail to adequately estimate prognosis and need for liver transplantation (LT) in ACLF. This study develops and validates a dynamic prediction model for patients with ACLF that uses both longitudinal and survival data.

Methods

Adult patients on the UNOS waitlist for LT between 11.01.2016-31.12.2019 were included. Repeated model for end-stage liver disease-sodium (MELD-Na) measurements were jointly modelled with Cox survival analysis to develop the ACLF joint model (ACLF-JM). Model validation was carried out using separate testing data with area under curve (AUC) and prediction errors. An online ACLF-JM tool was created for clinical application.

Results

In total, 30,533 patients were included. ACLF grade 1 to 3 was present in 16.4%, 10.4% and 6.2% of patients, respectively. The ACLF-JM predicted survival significantly (p <0.001) better than the MELD-Na score, both at baseline and during follow-up. For 28- and 90-day predictions, ACLF-JM AUCs ranged between 0.840-0.871 and 0.833-875, respectively. Compared to MELD-Na, AUCs and prediction errors were improved by 23.1%-62.0% and 5%-37.6% respectively. Also, the ACLF-JM could have prioritized patients with relatively low MELD-Na scores but with a 4-fold higher rate of waiting list mortality.

Conclusions

The ACLF-JM dynamically predicts outcome based on current and past disease severity. Prediction performance is excellent over time, even in patients with ACLF-3. Therefore, the ACLF-JM could be used as a clinical tool in the evaluation of prognosis and treatment in patients with ACLF.

Lay summary

Acute-on-chronic liver failure (ACLF) progresses rapidly and often leads to death. Liver transplantation is used as a treatment and the sickest patients are treated first. In this study, we develop a model that predicts survival in ACLF and we show that the newly developed model performs better than the currently used model for ranking patients on the liver transplant waiting list.

•

ACLF is a dynamic disease that can rapidly change over time, which greatly influences patient survival without LT.

•

Currently, the MELD-Na score is used to prioritize patients for LT, but MELD-Na underestimates ACLF disease severity.

•

The ACLF joint model (ACLF-JM) was developed to dynamically predict survival.

•

The ACLF-JM significantly outperformed the MELD-Na score for the prediction of mortality on the LT waiting list.

•

The ACLF-JM can be used online to predict survival in individual patients.

Joint modeling of liver transplant candidates outperforms the model for end-stage liver disease: The effect of disease development over time on patient outcome

Liver function is measured regularly in liver transplantation (LT) candidates. Currently, these previous disease development data are not used for survival prediction. By constructing and validating joint models (JMs), we aimed to predict the outcome based on all available data, using both disease severity and its rate of change over time. Adult LT candidates listed in Eurotransplant between 2007 and 2018 (n = 16 283) and UNOS between 2016 and 2019 (n = 30 533) were included. Patients with acute liver failure, exception points, or priority status were excluded. Longitudinal MELD(-Na) data were modeled using spline-based mixed effects. Waiting list survival was modeled with Cox proportional hazards models. The JMs combined the longitudinal and survival analysis. JM 90-day mortality prediction performance was compared to MELD(-Na) in the validation cohorts. MELD(-Na) score and its rate of change over time significantly influenced patient survival. The JMs significantly outperformed the MELD(-Na) score at baseline and during follow-up. At baseline, MELD-JM AUC and MELD AUC were 0.94 (0.92-0.95) and 0.87 (0.85-0.89), respectively. MELDNa-JM AUC was 0.91 (0.89-0.93) and MELD-Na AUC was 0.84 (0.81-0.87). The JMs were significantly (p < .001) more accurate than MELD(-Na). After 90 days, we ranked patients for LT based on their MELD-Na and MELDNa-JM survival rates, showing that MELDNa-JM-prioritized patients had three times higher waiting list mortality.

COVID-19 pandemic and worldwide organ transplantation: a population-based study

BACKGROUND

Preliminary data suggest that COVID-19 has reduced access to solid organ transplantation. However, the global consequences of the COVID-19 pandemic on transplantation rates and the effect on waitlisted patients have not been reported. We aimed to assess the effect of the COVID-19 pandemic on transplantation and investigate if the pandemic was associated with heterogeneous adaptation in terms of organ transplantation, with ensuing consequences for waitlisted patients.

METHODS

In this population-based, observational, before-and-after study, we collected and validated nationwide cohorts of consecutive kidney, liver, lung, and heart transplants from 22 countries. Data were collected from Jan 1 to Dec 31, 2020, along with data from the same period in 2019. The analysis was done from the onset of the 100th cumulative COVID-19 case through to Dec 31, 2020. We assessed the effect of the pandemic on the worldwide organ transplantation rate and the disparity in transplant numbers within each country. We estimated the number of waitlisted patient life-years lost due to the negative effects of the pandemic. The study is registered with ClinicalTrials.gov, NCT04416256.

FINDINGS

Transplant activity in all countries studied showed an overall decrease during the pandemic. Kidney transplantation was the most affected, followed by lung, liver, and heart. We identified three organ transplant rate patterns, as follows: countries with a sharp decrease in transplantation rate with a low COVID-19-related death rate; countries with a moderate decrease in transplantation rate with a moderate COVID-19-related death rate; and countries with a slight decrease in transplantation rate despite a high COVID-19-related death rate. Temporal trends revealed a marked worldwide reduction in transplant activity during the first 3 months of the pandemic, with losses stabilising after June, 2020, but decreasing again from October to December, 2020. The overall reduction in transplants during the observation time period translated to 48 239 waitlisted patient life-years lost.

INTERPRETATION

We quantified the impact of the COVID-19 pandemic on worldwide organ transplantation activity and revealed heterogeneous adaptation in terms of organ transplantation, both at national levels and within countries, with detrimental consequences for waitlisted patients. Understanding how different countries and health-care systems responded to COVID-19-related challenges could facilitate improved pandemic preparedness, notably, how to safely maintain transplant programmes, both with immediate and non-immediate life-saving potential, to prevent loss of patient life-years.

FUNDING

French national research agency (INSERM) ATIP Avenir and Fondation Bettencourt Schueller.

Does kidney transplantation with a standard or expanded criteria donor improve patient survival? Results from a Belgian cohort

BACKGROUND

Changes in recipient and donor factors have reopened the question of survival benefits of kidney transplantation versus dialysis.

METHODS

We analysed survival among 3808 adult Belgian patients waitlisted for a first deceased donor kidney transplant from 2000 to 2012. The primary outcome was mortality during the median waiting time plus 3 years of follow-up after transplantation or with continued dialysis. Outcomes were analysed separately for standard criteria donor (SCD) and expanded criteria donor (ECD) kidney transplants. We adjusted survival analyses for recipient age (20-44, 45-64 and ≥65 years), sex and diabetes as the primary renal disease.

RESULTS

Among patients ≥65 years of age, only SCD transplantation provided a significant survival benefit compared with dialysis, with a mortality of 16.3% [95% confidence interval (CI) 13.2-19.9] with SCD transplantation, 20.5% (95% CI 16.1-24.6) with ECD transplantation and 24.6% (95% CI 19.4-29.5) with continued dialysis. Relative mortality risk was increased in the first months after transplantation compared with dialysis, with equivalent risk levels reached earlier with SCD than ECD transplantation in all age groups.

CONCLUSIONS

The results of this study suggest that older patients might gain a survival benefit with SCD transplantation versus dialysis, but any survival benefit with ECD transplantation versus dialysis may be small.

Refitting the Model for End-Stage Liver Disease for the Eurotransplant Region

BACKGROUND AND AIMS

The United Network for Organ Sharing's Model for End-Stage Liver Disease (UNOS-MELD) score is the basis of liver allocation in the Eurotransplant region. It was constructed 20 years ago in a small US cohort and has remained unchanged ever since. The best boundaries and coefficients were never calculated for any region outside the United States. Therefore, this study refits the MELD (reMELD) for the Eurotransplant region.

APPROACH AND RESULTS

All adult patients listed for a first liver transplantation between January 1, 2007, and December 31, 2018, were included. Data were randomly split in a training set (70%) and a validation set (30%). In the training data, generalized additive models with splines were plotted for each MELD parameter. The lower and upper bound combinations with the maximum log-likelihood were chosen for the final models. The refit models were tested in the validation data with C-indices and Brier scores. Through likelihood ratio tests the refit models were compared to UNOS-MELD. The correlation between scores and survival of prioritized patients was calculated. A total of 6,684 patients were included. Based on training data, refit parameters were capped at creatinine 0.7-2.5, bilirubin 0.3-27, international normalized ratio 0.1-2.6, and sodium 120-139. ReMELD and reMELD-Na showed C-indices of 0.866 and 0.869, respectively. ReMELD-Na prioritized patients with 1.6 times higher 90-day mortality probabilities compared to UNOS-MELD.

CONCLUSIONS

Refitting MELD resulted in new lower and upper bounds for each parameter. The predictive power of reMELD-Na was significantly higher than UNOS-MELD. ReMELD prioritized patients with higher 90-day mortality rates. Thus, reMELD(-Na) should replace UNOS-MELD for liver graft allocation in the Eurotransplant region.

Validation of the Model for End-stage Liver Disease sodium (MELD-Na) score in the Eurotransplant region

The MELD score is used in the Eurotransplant (ET) region to allocate liver grafts. Hyponatremia in cirrhotic patients is an important predictor of death but is not incorporated in MELD. This study investigated the performance of the MELD-Na score for the ET region. All adult patients with chronic liver disease on the ET liver transplantation waiting list (WL) allocated through lab MELD scores were included. The MELD-corrected effect of serum sodium (Na) concentration at listing on the 90-day WL mortality was calculated using Cox regression. The MELD-Na performance was assessed with c-indices, calibration per decile and Brier scores. The reclassification from MELD to MELD-Na score was calculated to estimate the impact of MELD-Na-based allocation in the ET region. For the 5223 included patients, the risk of 90-day WL death was 2.9 times higher for hyponatremic patients. The MELD-Na had a significantly higher c-index of 0.847 (SE 0.007) and more accurate 90-day mortality prediction compared to MELD (Brier score of 0.059 vs 0.061). It was estimated that using MELD-Na would reduce WL mortality by 4.9%. The MELD-Na score yielded improved prediction of 90-day WL mortality in the ET region and using MELD-Na for liver allocation will very likely reduce WL mortality.

P1630IS THERE ALWAYS A SURVIVAL BENEFIT WITH KIDNEY TRANSPLANTATION? RESULTS FROM A BELGIAN COHORT

Background and Aims

Older studies have shown a survival benefit with kidney transplantation compared to dialysis, even for patients older than 60 years. However, due to important evolutions such as older recipient age and the use of less-than-optimal quality donors, it is unclear if the survival benefit with transplantation still holds true nowadays.

Method

Patient survival was analyzed for 3808 Belgian patients waitlisted for a first deceased donor kidney transplant between 2000 to 2012. Patients were divided into age categories (20-44y, 45-64y, ≥65y). Primary outcome was the comparison of mortality during median waiting time plus 3 years follow-up, either after transplantation or when remaining on dialysis. Outcomes were analyzed separately for those receiving a standard criteria donor (SCD) or an expanded criteria donor (ECD) transplant. The survival analyses were adjusted for age, sex and primary renal disease.

Results

Among patients ≥ 65 years old, only SCD transplantation provided a significant survival benefit compared to dialysis: mortality was 16.3 % (95 % CI: 13.2–19.9 %) with SCD transplantation, 20.5 % (16.1–24.6 %) with ECD transplantation, and 24.6 % (19.5–29.5 %) when remaining on dialysis. Relative mortality risk was increased in the first months after transplantation compared to dialysis, with equal risk levels being reached earlier for SCD than ECD transplantations in all age groups.

Conclusion

This study suggests that older patients have a survival benefit with SCD transplantation versus dialysis, but the survival benefit with ECD transplantation versus dialysis may be small or non-existent.

Allocation of liver grafts worldwide - Is there a best system?

BACKGROUND & AIMS

An optimal allocation system for scarce resources should simultaneously ensure maximal utility, but also equity. The most frequent principles for allocation policies in liver transplantation are therefore criteria that rely on pre-transplant survival (sickest first policy), post-transplant survival (utility), or on their combination (benefit). However, large differences exist between centers and countries for ethical and legislative reasons. The aim of this study was to report the current worldwide practice of liver graft allocation and discuss respective advantages and disadvantages.

METHODS

Countries around the world that perform 95 or more deceased donor liver transplantations per year were analyzed for donation and allocation policies, as well as recipient characteristics.

RESULTS

Most countries use the model for end-stage liver disease (MELD) score, or variations of it, for organ allocation, while some countries opt for center-based allocation systems based on their specific requirements, and some countries combine both a MELD and center-based approach. Both the MELD and center-specific allocation systems have inherent limitations. For example, most countries or allocation systems address the limitations of the MELD system by adding extra points to recipient's laboratory scores based on clinical information. It is also clear from this study that cancer, as an indication for liver transplantation, requires special attention.

CONCLUSION

The sickest first policy is the most reasonable basis for the allocation of liver grafts. While MELD is currently the standard for this model, many adjustments were implemented in most countries. A future globally applicable strategy should combine donor and recipient factors, predicting probability of death on the waiting list, post-transplant survival and morbidity, and perhaps costs.

LAY SUMMARY

An optimal allocation system for scarce resources should simultaneously ensure maximal utility, but also equity. While the model for end-stage liver disease is currently the standard for this model, many adjustments were implemented in most countries. A future globally applicable strategy should combine donor and recipient factors predicting probability of death on the waiting list, post-transplant survival and morbidity, and perhaps costs.