Allocation of donor livers--is MELD enough?

MELD3.0 is superior to MELDNa and MELD for prediction of mortality in patients with cirrhosis: An external validation in a multi-ethnic population

Background and Aim

The model for end-stage liver disease (MELD) was updated to MELDNa and recently to MELD3.0 to predict survival of cirrhotic patients. We validated the prognostic performance of MELD3.0 and compared with MELDNa and MELD amongst cirrhotic inpatients.

Methods

Demographical, clinical, biochemical, and survival data of cirrhotic inpatients in Singapore General Hospital (SGH) from 01 January 2018 to 31 December 2018, were studied retrospectively. Patients were followed up from first admission in 2018 until death or until 01 April 2023. Area under the receiver operating characteristic curves (AUROC) were computed for the discriminative effects of MELD3.0, MELDNa, and MELD to predict 30-, 90-, and 365-day mortalities. AUROC was compared with DeLong's test. The cutoff MELD3.0 score for patients at high risk of 30-day mortality was determined using Youden's Index. Survival curves of patients with MELD3.0 score above and below the cutoff were estimated with Kaplan-Meier method and compared with log-rank analysis.

Results

Totally 862 patients were included (median age 71.0 years [interquartile range, IQR: 64.0-79.0], 65.4% males, 75.8% Chinese). Proportion of patients with Child-Turcotte-Pugh classes A/B/C were 55.5%/35.5%/9.0%. Median MELD3.0/MELDNa/MELD scores were 12.2 (IQR: 8.7-18.3)/11.0 (IQR: 8.0-17.5)/10.3 (IQR: 7.8-15.0). Median time of follow-up was 51.9 months (IQR: 8.5-59.6). The proportion of 30-/90-/365-day mortalities was 5.7%/13.2%/26.9%. AUROC of MELD3.0/MELDNa/MELD in predicting 30-, 90-, and 365-day mortalities, respectively, were 0.823/0.793/0.783, 0.754/0.724/0.707, 0.682/0.654/0.644 (P < 0.05). Optimal cutoff to predict 30-day mortality was MELD3.0 > 19 (sensitivity = 67.4%, specificity = 82.4%). Patients with MELD3.0 > 19, compared with patients with MELD3.0 ≤ 19, had shorter median time to death (98.0 days [IQR: 28.8-398.0] vs 390.0 days [IQR: 134.3-927.5]), and higher proportion of 30-day mortality (68.8% vs 43.0%) (P < 0.001).

Conclusion

MELD3.0 performs better than MELDNa and MELD in predicting mortality in cirrhotic inpatients. MELD3.0 > 19 predicts higher 30-day mortality.

National Liver Allocation Policy-Consensus Document by the Liver Transplantation Society of India for a Nationally Uniform System of Allocation of Deceased Donor Liver Grafts

Background

Deceased donor liver transplantation (DDLT) is increasing in India and now constitutes nearly one-third of all liver transplantation procedures performed in the country. There is currently no uniform national system of allocation of deceased donor livers.

Methods

A national task force consisting of 19 clinicians involved in liver transplantation from across the country was constituted under the aegis of the Liver Transplantation Society of India to develop a consensus document addressing the above issues using a modified Delphi process of consensus development.

Results

The National Liver Allocation Policy consensus document includes 46 statements covering all aspects of DDLT, including minimum listing criteria, listing for acute liver failure, DDLT wait-list management, system of prioritisation based on clinical urgency for adults and children, guidelines for allocation of paediatric organs and allocation priorities for liver grafts recovered from public sector hospitals.

Conclusion

This document is the first step in the setting up of a nationally consistent policy of deceased donor liver allocation.

Model for End-Stage Liver Disease and liver cirrhosis-related complications

The Model for End-Stage Liver Disease (MELD) score has gained wide acceptance for predicting survival in patients undergoing liver transplantation. The strength of this score remains in the mathematical formula derived from a multivariate Cox regression analysis; it is a continuous scale and lacks a ceiling or a floor effect with a wide range of discrimination. It is based on objective, reproducible, and readily available laboratory data and the wide range of samples which have been validated. Liver cirrhosis complications such as ascites, encephalopathy, spontaneous bacterial peritonitis and variceal bleeding were not considered in the MELD score underestimating their direct association with the severity of liver disease. In this regard, several recent studies have shown that clinical manifestations secondary to portal hypertension are good prognostic markers in cirrhotic patients and may add additional useful prognostic information to the current MELD. We review the feasibility of MELD score as a prognostic predictor in patients with liver cirrhosis-related complications.

Outcome predictors of cirrhotic patients with spontaneous bacterial empyema

BACKGROUND

Spontaneous bacterial empyema (SBE) is a complication of cirrhotic patients in which a pre-existing pleural effusion becomes infected. This retrospective study was designed to investigate the bacteriology and outcome predictors of SBE in cirrhotic patients.

METHODS

Medical records of cirrhotic patients treated in a tertiary care university hospital from December 2004 to December 2008 were retrospectively reviewed.

RESULTS

Of 3390 cirrhotic patients seen during the study period, 81 cases of SBE were diagnosed. The incidence of SBE was 2.4% (81/3390) in cirrhotic patients and 16% (81/508) in patients with cirrhosis with hydrothorax. There were 46 monomicrobial infections found in 46 SBE patients. Aerobic Gram-negative organisms were the predominant pathogens (n=29, 63%), and Escherichia coli (n=9, 20%) was the most frequently isolated sole pathogen. The mortality rate of SBE was 38% (31/81). Univariate analysis showed that Child-Pugh score, model for end-stage liver disease (MELD)-Na score, concomitant bacteraemia, concomitant spontaneous bacterial peritonitis, initial intensive care unit (ICU) admission and initial antibiotic treatment failure were predictors of poor outcomes. Multivariate regression analysis demonstrated that the independent factors related to a poor outcome were initial ICU admission [odds ratio (OR): 4.318; 95% confidence interval 1CI) 1.09-17.03; P=0.037], MELD-Na score (OR: 1.267; 95% CI 1.08-1.49; P=0.004) and initial antibiotic treatment failure (OR: 13.10; 95% CI 2.60-66.03).

CONCLUSION

Spontaneous bacterial empyema in cirrhotic patients is a high mortality complication. The independent factors related to poor outcome are high MELD-Na score, initial ICU admission and initial antibiotic treatment failure. High MELD-Na score may be a useful mortality predictor of SBE in cirrhotic patients.

Prioritization for liver transplantation

There are three possible policies for prioritization for liver transplantation: medical urgency, utility and transplant benefit. The first is based on the severity of cirrhosis, using Child-Turcotte-Pugh score and, more recently, the Model for End-stage Liver Disease (MELD) score, or variants of MELD, for allocation. Although prospectively developed and validated, the MELD score has several limitations, including interlaboratory variations for measurement of serum creatinine and international normalized ratio of prothrombin time, and a systematic adverse female gender bias. Adjustments to the original MELD equation and new scoring systems have been proposed to overcome these limitations; incorporation of serum sodium improves its predictive accuracy. The MELD score poorly predicts outcomes after liver transplantation due to the absence of donor factors incorporated into the scoring system. Several utility models are based on donor and recipient characteristics. Combined poor recipient and donor characteristics lead to very poor outcomes, which in a utility system would be considered unacceptable. Finally, transplant benefit models rank patients according to the net survival benefit that they would derive from transplantation. However, complex statistical models are required, and unmeasured characteristics may unduly affect the models. Well-designed prospective studies and simulation models are necessary to establish the optimal allocation system in liver transplantation.

Comparison of four models for end-stage liver disease in evaluating the prognosis of cirrhosis

AIM: To investigate the prognostic value of the model for end-stage liver disease (MELD) and three new MELD-based models combination with serum sodium in decompensated cirrhosis patients-the MELD with the incorporation of serum sodium (MELD-Na), the integrated MELD (iMELD), and the MELD to sodium (MESO) index.

METHODS: A total of 166 patients with decompensated cirrhosis were enrolled into the study. MELD, MELD-Na, iMELD and MESO scores were calculated for each patient following the original formula on the first day of admission. All patients were followed up at least 1 year. The predictive prognosis related with the four models was determined by the area under the receiver operating characteristic curve (AUC) of the four parameters. Kaplan-Meier survival curves were made using the cut-offs identified by means of receiver operating characteristic (ROC).

RESULTS: Out of 166 patients, 38 patients with significantly higher MELD-Na (28.84 ± 2.43 vs 14.72 ± 0.60), iMELD (49.04 ± 1.72 vs 35.52 ± 0.67), MESO scores (1.59 ± 0.82 vs 0.99 ± 0.42) compared to the survivors died within 3 mo (P < 0.001). Of 166 patients, 75 with markedly higher MELD-Na (23.01 ± 1.51 vs 13.78 ± 0.69), iMELD (44.06 ± 1.19 vs 34.12 ± 0.69), MESO scores (1.37 ± 0.70 vs 0.93 ± 0.40) than the survivors died within 1 year (P < 0.001). At 3 mo of enrollment, the iMELD had the highest AUC (0.841), and was followed by the MELD-Na (0.766), MESO (0.723), all larger than MELD (0.773); At 1 year, the iMELD still had the highest AUC (0.783), the difference between the iMELD and MELD was statistically significant (P < 0.05). Survival curves showed that the three new models were all clearly discriminated the patients who survived or died in short-term as well as intermediate-term (P < 0.001).

CONCLUSION: Three new models, changed with serum sodium (MELD-Na, iMELD, MESO) can exactly predict the prognosis of patients with decompensated cirrhosis for short and intermediate period, and may enhance the prognostic accuracy of MELD. The iMELD is better prognostic model for outcome prediction in patients with decompensated cirrhosis.

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Selecting an optimal prognostic system for liver cirrhosis: the model for end-stage liver disease and beyond

In comparison with the Child-Turcotte-Pugh (CTP) system, recent studies suggested that the model for end-stage liver disease (MELD) may more accurately predict the survival for patients with cirrhosis. In the US, the liver allocation system was changed in 2002 from a status-based algorithm utilizing CTP scores to one using continuous MELD severity scores as a reference system in prioritizing adult patients on the waiting list. Direct evidence that demonstrates the benefits of MELD is the fact that the mortality rates of transplant candidates on the waiting list have remarkably decreased after the implementation of the MELD. The MELD score is closely associated with the degree of portal hypertension as reflected by the hepatic venous pressure gradient. Hyponatraemia occurs as a result of advanced cirrhosis, and a serum sodium (Na) level <126 mEq/L at the time of listing for transplantation is a strong independent predictor of mortality. Several MELD-derived prognostic models that incorporate serum Na into calculation have been proposed in the hopes of further improving the MELD's prognostic accuracy. Additionally, serum parameters such as creatinine and international normalized ratio are subject to interlaboratory variations and may need unifying standartisations. Patients with refractory complications of cirrhosis may need a priority MELD score to prioritize them on the waiting list. Appropriate modifications and the fine-tuning of the MELD based on well-designed prospective studies are necessary in solving the current controversial issues.

An integrated MELD model including serum sodium and age improves the prediction of early mortality in patients with cirrhosis

The Model for End-Stage Liver Disease (MELD) is widely used to predict the short-term mortality in patients with cirrhosis, but potential limitations of this score have been reported. The aim of this study was to improve the score's prognostic accuracy by assessing new objective variables. Data of 310 consecutive patients with cirrhosis who underwent elective transjugular intrahepatic portosystemic shunt placement between July 1995 and March 2005 were analyzed retrospectively. Bivariate and multivariate analyses were performed by proportional hazard Cox regression models. The area under the receiver operating characteristic curve (auROC) and the likelihood ratio test were used to evaluate the performance of the models for predicting early mortality. Findings were validated in a cohort of 451 consecutive patients with cirrhosis on waiting list for liver transplantation. Bivariate analyses showed that the following variables correlated with time to death: age, serum bilirubin, serum creatinine, international normalized ratio of prothrombin time, serum albumin, serum sodium, and MELD. Multivariate analysis revealed that MELD, serum sodium, and age were independently associated with the risk of death. The integrated MELD model (iMELD, incorporating serum sodium and age) was better than original MELD in predicting 12-month mortality: auROC increased by 13.4% and the likelihood ratio statistic from 23.5 to 48.2. The improved accuracy of iMELD was confirmed in the validation sample of 451 patients with cirrhosis on the waiting list for liver transplantation by increasing auROC (+8%) and likelihood ratio statistic (from 41.4 to 82.0). This study shows that in patients with cirrhosis, serum sodium and age are predictors of mortality independent of the MELD score. The incorporation of these variables into the original MELD formula improves the predictive accuracy of time to death.

Development and validation of a model predicting graft survival after liver transplantation

This study aimed to develop and validate a comprehensive model that predicts survival after liver transplantation based on pretransplant donor and recipient characteristics. Complete data were available from the United Network for Organ Sharing for 20,301 persons who underwent liver transplantation in the United States between 1994 and 2003. Proportional-hazards regression was used to identify the donor and recipient characteristics that best predicted survival and incorporate these characteristics in a multivariate model. A data-splitting approach was used to compare survival predicted by the model to the observed survival in samples not used in the derivation of the model. A model was derived using 4 donor characteristics (age, cold ischemia time, gender, and race/ethnicity) and 9 recipient characteristics (age, body max index, model for end-stage liver disease score, United Network for Organ Sharing priority status, gender, race/ethnicity, diabetes mellitus, cause of liver disease, and serum albumin) that adequately predicted survival after liver transplantation in patients without hepatitis C virus, and a slightly different model was used for patients with hepatitis C virus. The models illustrate that variations in both pretransplant donor and recipient characteristics have a large effect on posttransplant survival. In conclusion, the models presented here can be used to derive scores that are proportional to the excess risk of graft loss after liver transplantation for potential donors, recipients, or donor/recipient combinations. The models may be used to inform liver transplant candidates and their doctors what posttransplant survival would be expected when a given donor is offered and may be particularly helpful for marginal or high-risk donors.

A systematic review of the performance of the model for end-stage liver disease (MELD) in the setting of liver transplantation

The Model for End-Stage Liver Disease (MELD) score is now used for allocation in liver transplantation (LT) waiting lists, replacing the Child-Turcotte-Pugh (CTP) score. However, there is debate as whether it is superior to CTP score to predict mortality in patients with cirrhosis on the LT waiting list and after LT. We reviewed studies comparing the accuracy of MELD vs. CTP score in transplantation settings. We found that in studies of the LT waiting list (12,532 patients with cirrhosis), only 4 of 11 showed MELD to be superior to CTP in predicting short-term (3-month) mortality. In addition, 2 of 3 studies (n = 1,679) evaluating the changes in MELD score (DeltaMELD) showed that DeltaMELD had better prediction for mortality than the baseline MELD score. The impact of MELD on post-LT mortality was assessed in 15 studies (20,456 patients); only 6 (9,522 patients) evaluated the discriminative ability of MELD score using the concordance (c) statistic (the MELD score had always a c-statistic < 0.70). In 11 studies (19,311 patients), high MELD score indicated poor post-LT mortality for cutoff values of 24-40 points. In re-LT patients, 2 of 4 studies evaluated the discriminative ability of MELD score on post-LT mortality. Finally, several studies have shown that the predictive ability of MELD score increases by adding clinical variables (hepatic encephalopathy, ascites) or laboratory (sodium) parameters. On the basis of the current literature, MELD score does not perform better than the CTP score for patients with cirrhosis on the waiting list and cannot predict post-LT mortality.