Height contributes to the gender difference in wait-list mortality under the MELD-based liver allocation system

The liver allocation landscape: MELD 3.0 and continuous distribution

PURPOSE OF REVIEW

This review highlights recent advancements in liver organ allocation, specifically the transition to MELD 3.0 and the potential introduction of continuous distribution. These developments are timely, as they address the increasing need for a more efficient, equitable, and personalized system for prioritizing liver transplant candidates.

RECENT FINDINGS

The review covers two key innovations: MELD 3.0: A refined version of the original MELD score, designed to improve the prioritization process by incorporating additional factors that offer a more accurate and urgent measure of transplant need. This approach aims to better assess the severity of liver disease and the need for transplantation. Continuous distribution: A dynamic approach that shifts away from the static allocation model. It integrates multiple donor and recipient variables - such as geographic location, organ quality, and recipient condition - into a continuous, flexible allocation process. This framework seeks to make more nuanced decisions based on a broader set of factors that reflect transplant suitability.

SUMMARY

These innovations aim to enhance fairness and patient outcomes by refining candidate prioritization and reducing disparities in access to transplants. However, implementing these systems presents challenges, such as technical complexities and regional differences in access. Ongoing evaluation is necessary to ensure their effectiveness and equitable implementation across diverse patient populations.

Marked variation in disease acuity and outcomes on the liver transplant waiting list by sociodemographic characteristics

Understanding the association of social determinants of health with liver transplant listing and waitlist outcomes can inform health care policy and interventions aimed at improving access to care. We analyzed the Scientific Registry of Transplant Recipients database merged with the Social Deprivation Index (SDI) to evaluate if the area of residence is associated with the Model for End-Stage Liver Disease incorporating sodium (MELD-Na) at the time of waitlist placement and outcomes following waitlisting, and if this varied based on sociodemographic variables. Compared to candidates residing in areas of low SDI, those residing in areas of high SDI (most socioeconomic disadvantage) had 11% higher adjusted likelihood (aOR [95% CI] = 1.11 [CI 1.05,1.17]) of being listed for transplant with a MELD-Na score ≥30; this was not statistically significant when also adjusted for race/ethnicity (aOR = 1.02 [0.97,1.08]). When stratified by race/ethnicity, residing in an area of high SDI was associated with a MELD-Na score ≥30 at the time of waitlisting among Hispanic White candidates (aOR = 1.24, 95% CI: 1.04, 1.49). Candidates residing in areas of high SDI had an 8% lower chance (adjusted hazard ratio [aHR] = 0.92 [0.88,0.96]) of undergoing a liver transplant, a 6% higher risk of death (aHR = 1.06 [1.002,1.13]), and a 20% higher risk (aHR = 1.20 [1.13,1.28]) of removal on the waitlist independent of race, ethnicity, insurance status, or sex. In the United States, residence in areas of high socioeconomic disadvantage is significantly associated with higher MELD-Na at the time of waitlisting among Hispanic White candidates. In addition, residence in areas of high socioeconomic disadvantage was associated with a higher risk of death or removal from the waitlist and lower chances of receiving a liver transplant after waitlist placement, particularly among Non-Hispanic White candidates and older candidates.

Sex-based Differences and Comparative Predictive Value of MELD 3.0 in Simultaneous Liver-Kidney Transplantation Waitlist Outcomes After Standardization of Listing Criteria in the United States

Background

Sex disparities in solid organ transplantation are well documented. Relative changes in sex-based outcome disparities after the 2017 standardization of simultaneous liver-kidney (SLK) listing criteria in the United States have not been reported. We hypothesized that this policy's objective measures of kidney dysfunction may differentially affect SLK patients by sex and that the use of MELD 3.0 in the SLK population might provide unique benefit to female transplant candidates.

Methods

Organ Procurement and Transplantation Network data were retrospectively analyzed comparing 2013-2016 with 2018-2021 SLK listings. Waitlist outcomes and Model for End-stage Liver Disease (MELD) 3.0 reclassifications were compared by sex and listing period.

Results

There were 2626 and 2609 male patients and 1670 and 1919 female patients pre- and post-policy changes, respectively. The proportion of female SLK listings post-policy change (42.4%) was higher than both female SLK listings pre-policy change (38.9%) and female single-organ liver listings post-policy change (36.8%; P < 0.01). A statistically significant interaction between sex and listing group (pre- versus post-policy change) was present in multivariable analysis (P = 0.02). Female patients were more likely to have a higher MELD 3.0 score than the listing MELD/MELD-Na score when the listing MELD score was <30 (P < 0.01). Among all patients who died on the waitlist, female patients were nearly twice as likely to be underrepresented by listing MELD compared with MELD 3.0 (23% female and 13% male patients; P < 0.01).

Conclusions

Waitlist outcomes were changed differentially between male and female patients after the 2017 SLK policy change. The application of MELD 3.0 to SLK patients is likely to benefit female patients.

Expanding the Liver Donor Pool: Promise and Peril

Liver transplantation remains a life-saving therapy for a growing list of indications. Although 10,660 adult liver transplants were performed in the United States in 2023, a 50% increase over the preceding decade, the demand continues to far exceed the supply. Efforts to expand the liver donor pool by using donors that were previously considered unsuitable have remained an important strategy to help overcome shortages. We discuss the progress that has been made over the past decade, as well as potential future barriers that will need to be overcome to help successfully expand the liver donor pool.

Lesson learnt from 60 years of liver transplantation: Advancements, challenges, and future directions

Over the past six decades, liver transplantation (LT) has evolved from an experimental procedure into a standardized and life-saving intervention, reshaping the landscape of organ transplantation. Driven by pioneering breakthroughs, technological advancements, and a deepened understanding of immunology, LT has seen remarkable progress. Some of the most notable breakthroughs in the field include advances in immunosuppression, a revised model for end-stage liver disease, and artificial intelligence (AI)-integrated imaging modalities serving diagnostic and therapeutic roles in LT, paired with ever-evolving technological advances. Additionally, the refinement of transplantation procedures, resulting in the introduction of alternative transplantation methods, such as living donor LT, split LT, and the use of marginal grafts, has addressed the challenge of organ shortage. Moreover, precision medicine, guiding personalized immunosuppressive strategies, has significantly improved patient and graft survival rates while addressing emergent issues, such as short-term complications and early allograft dysfunction, leading to a more refined strategy and enhanced post-operative recovery. Looking ahead, ongoing research explores regenerative medicine, diagnostic tools, and AI to optimize organ allocation and post-transplantation car. In summary, the past six decades have marked a transformative journey in LT with a commitment to advancing science, medicine, and patient-centered care, offering hope and extending life to individuals worldwide.

Health disparities in cirrhosis care and liver transplantation

Morbidity and mortality from cirrhosis are substantial and increasing. Health disparities in cirrhosis and liver transplantation are reflective of inequities along the entire spectrum of chronic liver disease care, from screening and diagnosis to prevention and treatment of liver-related complications. The key populations experiencing disparities in health status and healthcare delivery include racial and ethnic minority groups, sexual and gender minorities, people of lower socioeconomic status and underserved rural communities. These disparities lead to delayed diagnosis of chronic liver disease and complications of cirrhosis (for example, hepatocellular carcinoma), to differences in treatment of chronic liver disease and its complications, and ultimately to unequal access to transplantation for those with end-stage liver disease. Calling out these disparities is only the first step towards implementing solutions that can improve health equity and clinical outcomes for everyone. Multi-level interventions along the care continuum for chronic liver disease are needed to mitigate these disparities and provide equitable access to care.

Systematic Sex-Based Inequity in the MELD Score-Based Allocation System for Liver Transplantation in Germany

In liver allocation systems based on the Model for End-stage Liver Disease (MELD) score, sex inequities have been identified in countries with high organ donation rates. Whether similar inequities exist in regions with average to low donation rates remained unclear. We assessed the impact of sex on transplantation rates, waiting list mortality and post-transplant survival in 25,943 patients waitlisted for liver transplantation in Germany between 2003 and 2017 using competing risk analysis. Women are currently underrepresented on the waiting list (33.3%) and among transplant recipients (31.1%) compared to their proportion of severe liver disease cases (35.1%). The introduction of MELD-based allocation has worsened this disadvantage [HR before: 0.89 (0.81-0.98), after: 0.77 (0.74-0.81)]. Three key factors contribute to this disparity: Women have lower creatinine levels despite worse renal function, reducing their MELD score (median 1, 0-3). Second, exceptional MELD points are more frequently granted to men [HR 1.61 (1.54-1.69) compared to regular allocation]. Third, the small height of women has the highest impact on the probability of not being transplanted [adjusted HR 0.85 (0.81-0.9)]. Even in countries with lower organ donation rates, MELD-based allocation leads to sex inequity. Measures are needed to ensure sex-neutral liver allocation in MELD-based systems worldwide.

Sex disparity in liver allocation within Eurotransplant

In Eurotransplant, relatively more females than males die while waiting for liver transplantation, and relatively fewer females undergo transplantation. With adult liver transplantation candidates listed between 2007 and 2019 (n = 21 170), we study whether sex disparity is inherent to the model for end-stage liver disease (MELD) scoring system, or the indirect result of a small candidate body size limiting access to transplantation. Cox proportional hazard models are used to quantify the direct effect of sex on waitlist mortality, independent of the effect of sex through MELD scores, and the direct effect of sex on the transplantation rate, independent of the effect of sex through MELD and candidate body size. Adjusted waitlist mortality hazard ratios (HRs) for female sex are insignificant (HR: 1.03, 95% CI: 0.88-1.20). We thus lack evidence that MELD systematically underestimates waitlist mortality rates for females. Transplantation rates are 25% lower for females than males in unadjusted analyses (HR: 0.74, 95% CI: 0.71-0.77), but HRs become insignificant with adjustment for mediators (HR: 0.98, 95% CI: 0.93-1.04), most importantly candidate body size. Sex disparity in Eurotransplant thus appears to be largely a consequence of lower transplantation rates for females, which are explained by sex differences in body size.

A Comprehensive Assessment of Liver Transplant Trends and Outcomes Among Adults With Steatotic Liver Disease in the U.S

Background and Aims

Steatotic liver disease (SLD) is the leading indication for liver transplantation (LT) among U.S. adults. We aim to provide comprehensive updates of LT trends and outcomes among adults with SLD, highlighting racial, ethnic, and sociodemographic disparities.

Methods

Using data from the 2010 to 2023 United Network for Organ Sharing registry, we performed a retrospective cohort study evaluating LT waitlist trends, waitlist outcomes, and post-LT survival among 65,675 adults with SLD. Disparities in LT outcomes were evaluated using adjusted competing risks analyses.

Results

From 2014 to 2023, there was an increasing proportion of Hispanics, women, and younger adults with SLD listed for LT. For Hispanics, this was driven by metabolic dysfunction-associated steatohepatitis (MASH); 19.9% of MASH wait-listings in 2023 were Hispanics. For women and younger adults (18-39 years), this was driven by alcohol-associated liver disease (ALD); 30.9% and 16.4% of ALD-related wait-listings in 2023 were women and younger adults, respectively. Women (vs men) had greater waitlist removal risk (subdistribution hazard ratio (sHR) 1.12, 95% confidence interval (CI) 1.07-1.18) and lower likelihood of LT receipt (sHR 0.87, 95% CI, 0.85-0.90). Ethnic minorities had worse outcomes, particularly Hispanics, who had a 37% higher risk of waitlist removal (sHR 1.37, 95% CI, 1.30-1.45) and 16% lower likelihood of LT receipt (sHR 0.86, 95% CI, 0.82-0.87) vs non-Hispanic whites. Disparities in post-LT survival were also observed.

Conclusion

In 2023, nearly one-quarter of MASH liver transplant waitlist registrants were Hispanics. Approximately half and 1 in 6 ALD waitlist registrants were women and younger adults, respectively. These concerning trends are amplified by the disparities in LT outcomes observed among women and ethnic minorities.

EASL Clinical Practice Guidelines on liver transplantation

Liver transplantation (LT) is an established life-saving procedure. The field of LT has changed in the past 10 years from several perspectives, with the expansion of indications, transplantation of patients with acute-on-chronic liver failure, evolution of transplant oncology, the use of donations after cardiac death, new surgical techniques, and prioritisation of recipients on the waiting list. In addition, the advent of organ perfusion machines, the recognition of new forms of rejection, and the attention paid to the transition from paediatric to adult patients, have all improved the management of LT recipients. The purpose of the EASL guidelines presented here is not to cover all aspects of LT but to focus on developments since the previous EASL guidelines published in 2016.

Sex and Size Disparities in Access to Liver Transplant for Patients With Hepatocellular Carcinoma

Importance

Women on the liver transplant waiting list are less likely to undergo a transplant than men. Recent approaches to resolving this disparity have involved adjustments to Model for End-Stage Liver Disease (MELD) scoring, but this will not affect candidates who rely on exception scores rather than calculated MELD score, the majority of whom have hepatocellular carcinoma (HCC).

Objective

To evaluate the association between female sex, candidate size, and access to liver transplant among wait-listed patients with HCC.

Design, Setting, and Participants

This retrospective cohort study used US transplant registry data of all adult (aged ≥18 years) wait-listed liver transplant candidates receiving an HCC exception score between January 1, 2010, and March 2, 2023.

Exposure

Wait-listed liver transplant candidate sex.

Main Outcomes and Measures

The association of female sex with (1) deceased-donor liver transplant (DDLT) and (2) death or waiting list removal for health deterioration were estimated using multivariable competing-risks regression. Results with and without adjustment for candidate height and weight (mediators of the sex disparity) were compared.

Results

The cohort included 31 725 candidates with HCC (mean [SD] age at receipt of exception, 61.2 [7.1] years; 76.3% men). Compared with men, women had a lower 1-year cumulative incidence of DDLT (50.8% vs 54.0%; P < .001) and a higher 1-year cumulative incidence of death or delisting for health deterioration (16.2% vs 15.0%; P = .002). After adjustment, without accounting for size, women had a lower incidence of DDLT (subdistribution hazard ratio [SHR], 0.92; 95% CI, 0.89-0.95) and higher incidence of death or delisting (SHR, 1.06; 95% CI, 1.00-1.13) compared with men. When adjusting for candidate height and weight, there was no association of female sex with incidence of DDLT or death or delisting. However, at a height cutoff of 166 cm, short women compared with short men were still less likely to undergo a transplant (SHR, 0.93; 95% CI, 0.88-0.99).

Conclusions and Relevance

In this study, women with HCC were less likely to receive a DDLT and more likely to die while wait-listed than men with HCC; these differences were largely (but not entirely) explained by sex-based differences in candidate size. For candidates listed with exception scores, additional changes to allocation policy are needed to resolve the sex disparity, including solutions to improve access to size-matched donor livers for smaller candidates.

Patient sex and use of tranexamic acid in liver transplantation

Background

Differences in medical treatment between women and men are common and involve out-of-hospital emergency care, the intensity of pain treatment, and the use of antifibrinolytic treatment in emergency trauma patients. If woman and man receive different antifibrinolytic treatment in highly-standardized major transplant surgery is unknown.

Methods

We conducted a retrospective cohort study on patients who underwent liver transplantation at Heidelberg University Hospital, Heidelberg, Germany between 2004 and 2017. Logistic regression analyses were performed to determine if sex is associated with the administration of TXA during liver transplantation. Secondary endpoints included venous thrombotic complications, graft failure, mortality, myocardial infarction, hepatic artery thrombosis, and stroke within the first 30 days after liver transplant as well as length of hospital stay and length of intensive care unit stay.

Results

Out of 779 patients who underwent liver transplantation, 262 patients received TXA. Female sex was not associated with intraoperative administration of TXA [adjusted OR: 0.929 (95% CI 0.654; 1.320), p = 0.681]. The secondary endpoints graft failure (13.2% vs. 8.4%, women vs. men, p = 0.039), pulmonary embolism (3.4% vs. 0.9%, women vs. men, p = 0.012), stroke (1.7% vs. 0.4%, women vs. men, p = 0.049), and deep vein thrombosis (0.8% vs. 0%, women vs. men, p = 0.031) within 30 days after liver transplantation were more frequent in women. Mortality, myocardial infarction, and other secondary endpoints did not differ between groups. However, in women, the use of TXA was associated with a lower rate in thromboembolic complications.

Conclusion

Our data indicate that different from other scenarios with massive bleeding complications the administration of TXA during liver transplantation is not associated with sex. However, sex is associated with the risk for complications, and in woman TXA might have a preventive effect on the rate of thromboembolic complications. Reasons underlying the observed sex bias rate remain uncertain.

Validation of MELD3.0 in 2 centers from different continents

BACKGROUND

MELD3.0 has been proposed to stratify patients on the liver transplant waiting list (WL) to reduce the historical disadvantage of women in accessing liver transplant. Our aim was to validate MELD3.0 in 2 unique populations.

METHODS

This study is a 2-center retrospective cohort study from Toronto, Canada, and Valencia, Spain, of all adults added to the liver transplant WL between 2015 and 2019. Listing indications whose short-term survival outcome is not adequately captured by the MELD score were excluded. All patients analyzed had a minimum follow-up of 3 months after inclusion in the WL.

RESULTS

Six hundred nineteen patients were included; 61% were male, with a mean age of 56 years. Mean MELD at inclusion was 18.00 ± 6.88, Model for End-Stage Liver Disease Sodium (MELDNa) 19.78 ± 7.00, and MELD3.0 20.25 ± 7.22. AUC to predict 90-day mortality on the WL was 0.879 (95% CI: 0.820, 0.939) for MELD, 0.921 (95% CI: 0.876, 0.967) for MELDNa, and 0.930 (95% CI: 0.888, 0.973) for MELD3.0. MELDNa and MELD3.0 were better predictors than MELD (p = 0.055 and p = 0.024, respectively), but MELD3.0 was not statistically superior to MELDNa (p = 0.144). The same was true when stratified by sex, although the difference between MELD3.0 and MELD was only significant for women (p = 0.032), while no statistical significance was found in either sex when compared with MELDNa. In women, AUC was 0.835 (95% CI: 0.744, 0.926) for MELD, 0.873 (95% CI: 0.785, 0.961) for MELDNa, and 0.886 (95% CI: 0.803, 0.970) for MELD3.0; differences for the comparison between AUC in women versus men for all 3 scores were nonsignificant. Compared to MELD, MELD3.0 was able to reclassify 146 patients (24%), the majority of whom belonged to the MELD 10-19 interval. Compared to MELDNa, it reclassified 68 patients (11%), most of them in the MELDNa 20-29 category.

CONCLUSIONS

MELD3.0 has been validated in centers with significant heterogeneity and offers the highest mortality prediction for women on the WL without disadvantaging men. However, in these cohorts, it was not superior to MELDNa.

Coronary artery calcium assessment on non-gated chest CT to optimize pre-operative cardiac screening in liver transplantation

BACKGROUND

Guidelines recommend standard pre-operative cardiac screening in all liver transplantation (LT) recipients, despite the relatively low prevalence of obstructive coronary artery disease. Most LT recipients often have non-gated computed tomography (CT) performed of the chest and abdomen. This study evaluated the ability of coronary artery calcification (CAC) assessment on consecutively available scans, to identify a selection of low-risk patients, in whom further cardiac imaging can be safely withheld.

METHODS

LT recipients with prior non-gated CT chest-abdomen were included. CAC was visually scored on a semi-quantitative ordinal scale. Stress myocardial perfusion, coronary CT angiography (CCTA) and invasive coronary angiography (ICA) were used as golden standard. The sensitivity and specificity of CAC to exclude and predict obstructive CAD were assessed. In addition, peri- and postoperative mortality and cardiac events were analyzed.

RESULTS

149 LT recipients (ranged 31-71 years) were included. In 75% of patients, no CAC and mild CAC could rule out obstructive CAD on CCTA and ICA with 100% certainty. The threshold of mild CAC had a sensitivity of 100% for both CCTA and ICA and a specificity of 91% and 68%, respectively. None of the patients with no or mild calcifications experienced peri- and post-operative cardiac events or died of cardiac causes.

CONCLUSION

Visual evaluation of CAC on prior non-gated CT can accurately and safely exclude obstructive CAD in LT recipients. Incorporation of these already available data can optimize cardiac screening, by safely withholding or correctly allocating dedicated cardiac imaging in LT recipients. Thereby, reducing patients' test burden and save health care expenses.

Evaluating the Correlation Between Anteroposterior Diameter, Body Surface Area, and Height for Liver Transplant Donors and Recipients

Background

Small stature and female sex correlate to decreased deceased donor liver transplant (DDLT) access and higher waitlist mortality. However, efforts are being made to improve access and equity of allocation under the new continuous distribution (CD) system. Liver anteroposterior diameter (APD) is a method used by many centers to determine size compatibility for DDLT but is not recorded systematically, so it cannot be used for allocation algorithms. We therefore seek to correlate body surface area (BSA) and height to APD in donors and recipients and compare waitlist outcomes by these factors to support their use in the CD system.

Methods

APD was measured from single-center DDLT recipients and donors with cross-sectional imaging. Linear, Pearson, and PhiK correlation coefficient were used to correlate BSA and height to APD. Competing risk analysis of waitlist outcomes was performed using United Network for Organ Sharing data.

Results

For 143 pairs, donor BSA correlated better with APD than height (PhiK = 0.63 versus 0.20). For recipient all comers, neither BSA nor height were good correlates of APD, except in recipients without ascites, where BSA correlated well (PhiK = 0.63) but height did not. However, among female recipients, BSA, but not height, strongly correlated to APD regardless of ascites status (PhiK = 0.80 without, PhiK = 0.70 with). Among male recipients, BSA correlated to APD only in those without ascites (PhiK = 0.74). In multivariable models, both BSA and height were predictive of waitlist outcomes, with higher values being associated with increased access, decreased delisting for death/clinical deterioration, and decreased living donor transplant (model concordance 0.748 and 0.747, respectively).

Conclusions

Taken together, BSA is a good surrogate for APD and can therefore be used in allocation decision making in the upcoming CD era to offset size and gender-based disparities among certain candidate populations.

Women Are Also Disadvantaged in Accessing Transplant Outside the United States: Analysis of the Spanish Liver Transplantation Registry

Sex inequities in liver transplantation (LT) have been documented in several, mostly US-based, studies. Our aim was to describe sex-related differences in access to LT in a system with short waiting times. All adult patients registered in the RETH-Spanish Liver Transplant Registry (2000-2022) for LT were included. Baseline demographics, presence of hepatocellular carcinoma, cause and severity of liver disease, time on the waiting list (WL), access to transplantation, and reasons for removal from the WL were assessed. 14,385 patients were analysed (77% men, 56.2 ± 8.7 years). Model for end-stage liver disease (MELD) score was reported for 5,475 patients (mean value: 16.6 ± 5.7). Women were less likely to receive a transplant than men (OR 0.78, 95% CI 0.63, 0.97) with a trend to a higher risk of exclusion for deterioration (HR 1.17, 95% CI 0.99, 1.38), despite similar disease severity. Women waited longer on the WL (198.6 ± 338.9 vs. 173.3 ± 285.5 days, p < 0.001). Recently, women's risk of dropout has reduced, concomitantly with shorter WL times. Even in countries with short waiting times, women are disadvantaged in LT. Policies directed at optimizing the whole LT network should be encouraged to guarantee a fair and equal access of all patients to this life saving resource.

Chronic Liver Disease and Cirrhosis Mortality Rates Are Disproportionately Increasing in Younger Women in the United States Between 2000-2020

BACKGROUND & AIMS

Previous studies show that mortality from chronic liver disease (CLD) and cirrhosis is increasing in the United States. However, there are limited data on sex-specific mortality trends by age, race, and geographical location. The aim of this study was to conduct a comprehensive time-trend analysis of liver disease-related mortality rates in the National Center of Health Statistics (NCHS) database.

METHODS

CLD and cirrhosis mortality rates between 20002020 (age-adjusted to the 2000 standard U.S. population) were collected from the NCHS database and categorized by sex and age into older adults (≥55 years) and younger adults (<55 years), race (Non-Hispanic-White, Non-Hispanic-Black, Hispanic, Non-Hispanic-American-Indian/Alaska-Native, and Non-Hispanic-Asian/Pacific-Islander), U.S. state, and cirrhosis etiology. Time trends, annual percentage change (APC), and average APC (AAPC) were estimated using Joinpoint Regression using Monte Carlo permutation analysis. We used tests for parallelism and identicalness for sex-specific pairwise comparisons of mortality trends (two-sided P value cutoff = .05).

RESULTS

Between 20002020, there were 716,651 deaths attributed to CLD and cirrhosis in the U.S. (35.68% women). In the overall population and in older adults, CLD and cirrhosis-related mortality rates were increasing similarly in men and women. However, in younger adults (246,149 deaths, 32.72% women), the rate of increase was greater in women compared with men (AAPC = 3.04 vs 1.08, AAPC-difference = 1.96; P < .001), with non-identical non-parallel data (P values < .001). The disparity was driven by Non-Hispanic-White (AAPC = 4.51 vs 1.79, AAPC-difference = 2.71; P < .001) and Hispanic (AAPC = 1.89 vs -0.65, AAPC-difference = 2.54; P = .001) individuals. The disparity varied between U.S. states and was seen in 16 states, mostly in West Virginia (AAPC = 4.96 vs 0.88, AAPC-difference = 4.08; P < .001) and Pennsylvania (AAPC = 2.81 vs -1.02, AAPC-difference = 3.84; P < .001). Etiology-specific analysis did not show significant sex disparity in younger adults.

CONCLUSIONS

Mortality rates due to CLD and cirrhosis in the U.S. are increasing disproportionately in younger women. This finding was driven by higher rates in Non-Hispanic White and Hispanic individuals, with variation between U.S. states. Future studies are warranted to identify the reasons for these trends with the ultimate goal of improving outcomes.

Model for end-stage liver disease-3.0 vs. model for end-stage liver disease-sodium: mortality prediction in Korea

BACKGROUND/AIMS

The model for end-stage liver disease (MELD) serves as an indicator for short-term mortality among patients diagnosed with liver cirrhosis (LC) and is used to prioritize patients for liver transplantation. In 2021, the updated version of MELD, MELD-3.0, was introduced to improve the accuracy of the mortality prediction of MELD. Therefore, this study aimed to compare the efficacy of MELD 3.0 and MELD-Na in predicting mortality among Korean patients with LC.

METHODS

A retrospective review was conducted using the medical records of patients diagnosed with LC who were admitted to Konkuk University Hospital From 2011 to 2021. The study calculated the predictive values of MELD-Na and MELD-3.0 for 3- and 6-months mortality using the area under the receiver operating curve (AUROC) and compared the results using the DeLong test.

RESULTS

Of the 3,034 patients enrolled in the study, 339 (11.2%) died within 3 months and 421 (14.4%) died within 6 months. The AUROCs values for predicting 3 months mortality were 0.846 for MELD-Na and 0.851 for MELD-3.0. The corresponding AUROC values for predicting 6 months mortality were 0.843 for MELD-Na and 0.848 for MELD-3.0. MELD-3.0 exhibited better discrimination ability than MELD-Na for both 3 (p = 0.03) and 6 months mortality (p = 0.01).

CONCLUSION

Our study found a significant difference between the performance of MELD-3.0 and MELD-Na in Korean patients with LC.

Practical Considerations When Choosing Chemoembolization versus Radioembolization for Hepatocellular Carcinoma

Transarterial chemoembolization (TACE) and transarterial radioembolization (TARE) are common liver-directed therapies (LDTs) for unresectable HCC. While both deliver intra-arterial treatment directly to the site of the tumor, they differ in mechanisms of action and side effects. Several studies have compared their side effect profile, time to progression, and overall survival data, but often these lack practical considerations when choosing which treatment modality to use. Many factors can impact operator's choice for treatment, and the choice depends on treatment availability, cost, insurance coverage, operator's comfort level, patient-specific factors, tumor location, tumor biology, and disease stage. This review discusses survival data, time to progression data, as well as more practical patient and tumor characteristics for personalized LDT with TACE or TARE.

MELD 3.0 in Advanced Chronic Liver Disease

The MELD (model for end-stage liver disease) 3.0 score was developed to replace the MELD-Na score that is currently used to prioritize liver allocation for cirrhotic patients awaiting liver transplantation in the United States. The MELD 3.0 calculator includes new inputs from patient sex and serum albumin levels and has new weights for serum sodium, bilirubin, international normalized ratio, and creatinine levels. It is expected that use of MELD 3.0 scores will reduce overall waitlist mortality modestly and improve access for female liver transplant candidates. The utility of MELD 3.0 and PELDcre (pediatric end-stage liver disease, creatinine) scores for risk stratification in cirrhotic patients undergoing major abdominal surgery, placement of a transjugular intrahepatic portosystemic shunt, and other interventions requires further study. This article reviews the background of the MELD score and the rationale to create MELD 3.0 as well as potential implications of using this newer risk stratification tool in clinical practice.

Superiority of the new sex-adjusted models to remove the female disadvantage restoring equity in liver transplant allocation

BACKGROUND AND AIMS

Model for End-stage Liver Disease (MELD) and MELDNa are used worldwide to guide graft allocation in liver transplantation (LT). Evidence exists that females are penalized in the present allocation systems. Recently, new sex-adjusted scores have been proposed with improved performance respect to MELD and MELDNa. GEMA-Na, MELD 3.0, and sex-adjusted MELDNa were developed to improve the 90-day dropout prediction from the list. The present study aimed at evaluating the accuracy and calibration of these scores in an Italian setting.

METHODS

The primary outcome of the present study was the dropout from the list up to 90 days because of death or clinical deterioration. We retrospectively analysed data from 855 adults enlisted for liver transplantation in the Lazio region (Italy) (2012-2018). Ninety-day prediction of GEMA-Na, MELD 3.0 and sex-adjusted MELDNa with respect to MELD and MELDNa was analysed. Brier score and Brier Skill score were used for accuracy, and the Greenwood-Nam-D'Agostino test was used to evaluate the calibration of the models.

RESULTS

GEMA-Na (concordance = .82, 95% CI = .75-.89), MELD 3.0 (concordance = .81, 95% CI = .74-.87) and sex-adjusted MELDNa (concordance = .81, 95% CI = .74-.88) showed the best 90-day dropout prediction. GEMA-Na showed a higher increase in accuracy with respect to MELD (p = .03). No superiority was shown with respect to MELDNa. All the tested scores showed a good calibration of the models. Using GEMA-Na instead of MELD would potentially save one in nine dropouts and could save one dropout per 285 patients listed.

CONCLUSIONS

Validation and reclassification of the sex-adjusted score GEMA-Na confirm its superiority in predicting short-term dropout also in an Italian setting when compared with MELD.

Sex-based Disparities in Access to Liver Transplantation for Waitlisted Patients With Model for End-stage Liver Disease Score of 40

OBJECTIVE

To determine the association of sex with access to liver transplantation among candidates with the highest possible model for end-stage liver disease score (MELD 40).

BACKGROUND

Women with end-stage liver disease are less likely than men to receive liver transplantation due in part to MELD's underestimation of renal dysfunction in women. The extent of the sex-based disparity among patients with high disease severity and equally high MELD scores is unclear.

METHODS

Using national transplant registry data, we compared liver offer acceptance (offers received at match MELD 40) and waitlist outcomes (transplant vs death/delisting) by sex for 7654 waitlisted liver transplant candidates from 2009 to 2019 who reached MELD 40. Multivariable logistic and competing-risks regression was used to estimate the association of sex with the outcome and adjust for the candidate and donor factors.

RESULTS

Women (N = 3019, 39.4%) spent equal time active at MELD 40 (median: 5 vs 5 days, P = 0.28) but had lower offer acceptance (9.2% vs 11.0%, P < 0.01) compared with men (N = 4635, 60.6%). Adjusting for candidate/donor factors, offers to women were less likely accepted (odds ratio = 0.87, P < 0.01). Adjusting for candidate factors, once they reached MELD 40, women were less likely to be transplanted (subdistribution hazard ratio = 0.90, P < 0.01) and more likely to die or be delisted (subdistribution hazard ratio = 1.14, P = 0.02).

CONCLUSIONS

Even among candidates with high disease severity and equally high MELD scores, women have reduced access to liver transplantation and worse outcomes compared with men. Policies addressing this disparity should consider factors beyond MELD score adjustments alone.

Mitigating Health Disparities in Transplantation Requires Equity, Not Equality

Despite decades of research and evidence-based mitigation strategies, disparities in access to transplantation persist for all organ types and in all stages of the transplant process. Although some strategies have shown promise for alleviating disparities, others have fallen short of the equity goal by providing the same tools and resources to all rather than tailoring the tools and resources to one's circumstances. Innovative solutions that engage all stakeholders are needed to achieve equity regardless of race, sex, age, socioeconomic status, or geography. Mitigation of disparities is paramount to ensure fair and equitable access for those with end-stage disease and to preserve the trust of the public, upon whom we rely for their willingness to donate organs. In this overview, we present a summary of recent literature demonstrating persistent disparities by stage in the transplant process, along with policies and interventions that have been implemented to combat these disparities and hypotheses for why some strategies have been more effective than others. We conclude with future directions that have been proposed by experts in the field and how these suggested strategies may help us finally arrive at equity in transplantation.

Sex and racial disparities in living donor liver transplantation in the United States

Sex and racial disparities in deceased donor liver transplantation (DDLT) have been described, but this has not been well studied in living donor liver transplantation (LDLT). We aim to examine these disparities in the US LDLT population and identify potential predictors of these differences. From 2002 to 2021, the Organ Procurement and Transplant Network database was queried to characterize the adult LDLT population and evaluate differences between LDLT and DDLT recipients with regard to sex and race. Donor demographics, Model for End-stage Liver Disease (MELD), and socioeconomic data were all included. Of the 4961 LDLT and 99,984 DDLT recipients, males received the majority of LDLT (55% vs. 45%, p < 0.001) and DDLT (67% vs. 33%, p < 0.001) compared to females. There was a significant difference in race between male and female LDLT recipients ( p < 0.001); 84% of male recipients were White and 78% of females. In both groups, females had lower levels of education and were less likely to have private insurance. There were more female living donors (N = 2545, 51%); 50% of female donors donated to males but only 40% of males donated to females. Donor-recipient relationships varied significantly by sex ( p < 0.001); males received more donations from spouses (62% vs. 39%) and siblings (60% vs. 40%). In the LDLT population, significant disparities exist with respect to sex and race that disadvantage women, but these disparities are less pronounced than in the DDLT population. Although further studies are needed, complex clinical and socioeconomic differences as well as donor factors may explain these variations.

Availability of living donor optimizes timing of liver transplant in high-risk waitlisted cirrhosis patients

Liver transplant (LT) candidates have become older and frailer, with growing Non-alcoholic steatohepatitis (NASH) and comorbid disease burden in recent years, predisposing them for poor waitlist outcomes. We aimed to evaluate the impact of access to living donor liver transplantation (LDLT) in waitlisted patients at highest risk of dropout. We reviewed all adult patients with decompensated cirrhosis listed for LT from November 2012 to December 2018. Patients with a potential living donor (pLD) available were identified. Survival analyses with Cox Proportional Hazards models and time to LT with Competing risk models were performed followed by prediction model development. Out of 860 patients who met inclusion criteria, 360 (41.8%) had a pLD identified and 496 (57.6%) underwent LT, out of which 170 (34.2%) were LDLT. The benefit of pLD was evident for all, but patients with moderate to severe frailty at listing (interaction p = 0.03), height <160 cm (interaction p = 0.03), and Model for end stage liver disease (MELD)-Na score <20 (interaction p < 0.0001) especially benefited. Our prediction model identified patients at highest risk of dropout while waiting for deceased donor and most benefiting of pLD (time-dependent area under the receiver operating characteristic curve 0.82). Access to LDLT in a transplant program can optimize the timing of transplant for the increasingly older, frail patient population with comorbidities who are at highest risk of dropout.

[Sex-specific differences in gastroenterological diseases]

Diseases of the gastrointestinal tract present with substantial sex differences that have a potential impact on patient outcome. This fact is not sufficiently addressed either in basic research or in clinical studies. For example, most animal studies utilize male animals. Despite differences in incidence, sex may affect complication rates, prognosis, or therapeutic response. The incidence of gastrointestinal cancers is frequently higher in males, but this observation cannot solely rely on a distinct risk behaviour. Here, differences in immune response and p53 signalling may be factors responsible for this finding. Nevertheless, taking sex differences into account and improving our understanding of relevant mechanisms is crucial and will most likely have a substantial impact on disease outcome. This overview aims to highlight sex differences in the context of various gastroenterological diseases, primarily to enhance awareness. Attention to sex-specific differences is essential to improve individualized treatment.

Actionable Solutions to Achieve Health Equity in Chronic Liver Disease

There are well-described racial and ethnic disparities in the burden of chronic liver diseases. Hispanic persons are at highest risk for developing nonalcoholic fatty liver disease, the fastest growing cause of liver disease. Hepatitis B disproportionately affects persons of Asian or African descent. The highest rates of hepatitis C occur in American Indian and Alaskan Native populations. In addition to disparities in disease burden, there are also marked racial and ethnic disparities in access to treatments, including liver transplantation. Disparities also exist by gender and geography, especially in alcohol-related liver disease. To achieve health equity, we must address the root causes that drive these inequities. Understanding the role that social determinants of health play in the disparate health outcomes that are currently observed is critically important. We must forge and/or strengthen collaborations between patients, community members, other key stakeholders, health care providers, health care institutions, professional societies, and legislative bodies. Herein, we provide a high-level review of current disparities in chronic liver disease and describe actionable strategies that have potential to bridge gaps, improve quality, and promote equity in liver care.

Revising the MELD Score to Address Sex-Bias in Liver Transplant Prioritization for a German Cohort

(1) Background: Prioritization of patients for liver transplantation in Germany relies on the MELD (model for end-stage liver disease) scoring system that does not consider the patient's sex. Many studies have shown that women are disadvantaged by the MELD score. Using a large patient cohort from a German liver transplant centre, we investigated options to reduce gender inequality in the patient prioritization for liver transplantation. (2) Methods: We calculated female-as-male MELD scores in our cohort by substituting the serum creatinine of a female patient with that of their male equivalent to test for the fairness of the scores. We investigated the effects of the female-as-male scores compared to the original MELD score of 1759 patients listed for liver transplantation. (3) Results: Serum creatinine sex correction (female-as-male) for MELD scores added up to 5.4 points in females, while the median changed by +1.6 points for females. We identified 72 females with an original MELD score < 20, for whom the adjusted female-as-male MELD score would be >20, thus giving them a better chance to receive a liver transplant. (4) Conclusions: Mathematical conversion of female to male creatinine concentrations identified disadvantages in liver transplantation prioritization for females and ascertained MELD 3.0 as having high potential to compensate for these inequalities.

Association of Body Surface Area With Access to Deceased Donor Liver Transplant and Novel Allocation Policies

Importance

Small waitlist candidates are significantly less likely than larger candidates to receive a liver transplant.

Objective

To investigate the magnitude of the size disparity and test potential policy solutions.

Design, Setting, and Participants

A decision analytical model was generated to match liver transplant donors to waitlist candidates based on predefined body surface area (BSA) ratio limits (donor BSA divided by recipient BSA). Participants included adult deceased liver transplant donors and waitlist candidates in the Organ Procurement and Transplantation Network database from June 18, 2013, to March 20, 2020. Data were analyzed from January 2021 to September 2021.

Exposures

Candidates were categorized into 6 groups according to BSA from smallest (group 1) to largest (group 6). Waitlist outcomes were examined. A match run was created for each donor under the current acuity circle liver allocation policy, and the proportion of candidates eligible for a liver based on BSA ratio was calculated. Novel allocation models were then tested.

Main Outcomes and Measures

Time on the waitlist, assigned Model for End-Stage Liver Disease (MELD) score, and proportion of patients undergoing a transplant were compared by BSA group. Modeling under the current allocation policies was used to determine baseline access to transplant by group. Simulation of novel allocation policies was performed to examine change in access.

Results

There were 41 341 donors (24 842 [60.1%] male and 16 499 [39.9%] female) and 84 201 waitlist candidates (53 724 [63.8%] male and 30 477 [36.2%] female) in the study. The median age of the donors was 42 years (IQR, 28-55) and waitlist candidates, 57 years (IQR, 50-63). Females were overrepresented in the 2 smallest BSA groups (7100 [84.0%] and 7922 [61.1%] in groups 1 and 2, respectively). For each increase in group number, waitlist time decreased (234 days [IQR, 48-700] for group 1 vs 179 days [IQR, 26-503] for group 6; P < .001) and the proportion of the group undergoing transplant likewise improved (3890 [46%] in group 1 vs 4932 [57%] in group 6; P < .001). The smallest 2 groups of candidates were disadvantaged under the current acuity circle allocation model, with 37% and 7.4% fewer livers allocated relative to their proportional representation on the waitlist. Allocation of the smallest 10% of donors (by BSA) to the smallest 15% of candidates overcame this disparity, as did performing split liver transplants.

Conclusions and Relevance

In this study, liver waitlist candidates with the smallest BSAs had a disadvantage due to size. Prioritizing allocation of smaller liver donors to smaller candidates may help overcome this disparity.

Donor, Recipient and Surgeon Sex and Sex-Concordance and their Impact on Liver Transplant Outcome

(1) Background: Patient sex is associated with differential outcome of many procedures although the exact mechanisms remain unknown. Especially in transplant surgery, surgeon-patient sex-concordance is rarely present for female patients and outcome may be negatively affected. (2) Methods: In this single-center retrospective cohort study, recipient, donor, and surgeon sex were evaluated and short- and long-term outcome was analyzed with regards to sex and sex-concordance of patients, donors, and surgeons. (3) Results: We included 425 recipients in our study; 50.1% of organ donors, 32.7% of recipients, and 13.9% of surgeons were female. Recipient-donor sex concordance was present in 82.7% of female recipients and in 65.7% of male recipients (p = 0.0002). Recipient-surgeon sex concordance was present in 11.5% of female recipients and in 85.0% of male recipients (p < 0.0001). Five-year patient survival was comparable between female and male recipients (70.0% vs. 73.3%, p = 0.3978). Five-year patient survival of female recipients treated by female surgeons was improved without reaching significance (81.3% vs. 68.4%, p = 0.3621). (4) Conclusions: Female recipients and female surgeons are underrepresented in liver transplant surgery. Societal factors influencing outcome of female patients suffering from end-stage organ failure need to be further examined and acted upon to possibly improve the outcome of female liver transplant recipients.

Survival Benefit of Split-Liver Transplantation for Pediatric and Adult Candidates

Patient and graft survival are similar following whole-liver transplantations (WLTs) versus split-liver transplantations (SLTs) among pediatric and adult recipients, yet SLTs are rarely used. We sought to determine the survival benefit associated with accepting a splittable graft offer for SLT versus declining and waiting for a subsequent offer using 2010 to 2018 Scientific Registry of Transplant Recipients (SRTR) data on 928 pediatric and 1814 adult liver transplantation candidates who were ever offered a splittable graft. We compared eventual mortality, regardless of subsequent transplants, between those patients who accepted versus declined a split liver offer with adjustments for Pediatric End-Stage Liver Disease/Model for End-Stage Liver Disease (MELD) scores, diagnosis, and weight among pediatric candidates and matching for MELD score, height, and offer among adult candidates. Among pediatric candidates ≤7 kg, split liver offer acceptance versus decline was associated with a 63% reduction in mortality (adjusted hazard ratio [aHR], _0.17 0.37_0.80 [P = 0.01]; 93.1% versus 84.0% 1-year survival after decision). Within 1 year of decline for those ≤7 kg, 6.4% died and 31.1% received a WLT. Among pediatric candidates >7 kg, there was no significant difference associated with acceptance of a split liver offer (aHR, _0.63 1.07_1.82 [P = 0.81]; 91.7% versus 94.4% 1-year survival after decision). Within 1 year of decline for those >7 kg, 1.8% died and 45.8% received a WLT. Among adult candidates, split liver offer acceptance was associated with a 43% reduction in mortality (aHR, _0.39 0.57_0.83 [P = 0.005]; 92.2% versus 84.4% 1-year survival after decision). Within 1 year of decline for adult candidates, 7.9% died and 39.3% received a WLT. Accepting split liver offers for SLT could significantly improve survival for small children and adults on the waiting list.

Are MELD and MELDNa Still Reliable Tools to Predict Mortality on the Liver Transplant Waiting List?

Liver transplantation is the only curative treatment for end-stage liver disease. Unfortunately, the scarcity of donor organs and the increasing pool of potential recipients limit access to this life-saving procedure. Allocation should account for medical and ethical factors, ensuring equal access to transplantation regardless of recipient's gender, race, religion, or income. Based on their short-term prognosis prediction, model for end-stage liver disease (MELD) and MELD sodium (MELDNa) have been widely used to prioritize patients on the waiting list for liver transplantation resulting in a significant decrease in waiting list mortality/removal. Recent concern has been raised regarding the prognostic accuracy of MELD and MELDNa due, in part, to changes in recipients' profile such as body mass index, comorbidities, and general condition, including nutritional status and cause of liver disease, among others. This review aims to provide a comprehensive view of the current state of MELD and MELDNa advantages and limitations and promising alternatives. Finally, it will explore future options to increase the donor pool and improve donor-recipient matching.

Mortality and Causes of Death After Liver Transplantation: Analysis of Sex Differences in a Large Nationwide Cohort

In the last few years, several studies have analyzed sex and gender differences in liver transplantation (LT), but none have performed a disaggregated analysis of both mortality and causes of death. Data from 15,998 patients, 11,914 (74.5%) males and 4,069 (25.5%) females, transplanted between 2000 and 2016 were obtained from the Liver Transplantation Spanish Registry. Survival analysis was applied to explore recipient sex as a risk factor for death. The causes of death at different follow-up duration were disaggregated by recipient sex for analysis. Short-term survival was higher in males, whereas long-term survival was higher in females. Survival at 1, 5 and 10 years post-transplant was 87.43%, 73.83%, and 61.23%, respectively, in males and 86.28%, 74.19%, and 65.10%, respectively, in females (p = 0.05). Post-LT mortality related to previous liver disease also presented sex differences. Males had 37% increased overall mortality from acute liver failure (p = 0.035) and 37% from HCV-negative cirrhosis (p < 0.001). Females had approximately 16% increased mortality when the liver disease was HCV-positive cirrhosis (p = 0.003). Regarding causes of death, non-malignancy HCV+ recurrence (6.3% vs. 3.9% of patients; p < 0.001), was more frequently reported in females. By contrast, death because of malignancy recurrence (3.9% vs. 2.2% of patients; p = 0.003) and de novo malignancy (4.8% vs. 2.5% of patients; p < 0.001) were significantly more frequent in male recipients. Cardiovascular disease, renal failure, and surgical complications were similar in both. In summary, male patients have lower short-term mortality than females but higher long-term and overall mortality. In addition, the post-LT mortality risk related to previous liver disease and the causes of mortality differ between males and females.

Nosocomial infections in female compared with male patients with decompensated liver cirrhosis

There are considerable differences between males and females regarding the etiology, progression and outcome of liver diseases. Infections are a frequent and severe complication in these patients. This study aimed to examine sex specific differences in the incidence and clinical course of nosocomial infections in patients with decompensated liver cirrhosis. A number of 556 consecutive hospitalized patients with decompensated liver cirrhosis and ascites were analyzed. The patients were followed up for the incidence of nosocomial infections, acute kidney injury (AKI), acute-on-chronic liver failure (ACLF) as well as liver transplantation and death (LTx-free survival). A number of 285 patients (111 women and 174 men) developed a nosocomial infection. Incidence was numerically lower in men (P = 0.076). While the frequency of a nosocomial spontaneous bacterial peritonitis was similar between males and females, the incidence of a nosocomial urinary tract infection was significantly higher in women (P < 0.001). No sex specific differences were documented regarding the outcome of an infection as indicated by a similar incidence of, AKI, ACLF as well as LTx-free survival. There seem to be no major differences in the incidence and outcome of nosocomial infections between male and female patients.

A scoping review of inequities in access to organ transplant in the United States

BACKGROUND

Organ transplant is the preferred treatment for end-stage organ disease, yet the majority of patients with end-stage organ disease are never placed on the transplant waiting list. Limited access to the transplant waiting list combined with the scarcity of the organ pool result in over 100,000 deaths annually in the United States. Patients face unique barriers to referral and acceptance for organ transplant based on social determinants of health, and patients from disenfranchised groups suffer from disproportionately lower rates of transplantation. Our objective was to review the literature describing disparities in access to organ transplantation based on social determinants of health to integrate the existing knowledge and guide future research.

METHODS

We conducted a scoping review of the literature reporting disparities in access to heart, lung, liver, pancreas and kidney transplantation based on social determinants of health (race, income, education, geography, insurance status, health literacy and engagement). Included studies were categorized based on steps along the transplant care continuum: referral for transplant, transplant evaluation and selection, living donor identification/evaluation, and waitlist outcomes.

RESULTS

Our search generated 16,643 studies, of which 227 were included in our final review. Of these, 34 focused on disparities in referral for transplantation among patients with chronic organ disease, 82 on transplant selection processes, 50 on living donors, and 61 on waitlist management. In total, 15 studies involved the thoracic organs (heart, lung), 209 involved the abdominal organs (kidney, liver, pancreas), and three involved multiple organs. Racial and ethnic minorities, women, and patients in lower socioeconomic status groups were less likely to be referred, evaluated, and added to the waiting list for organ transplant. The quality of the data describing these disparities across the transplant literature was variable and overwhelmingly focused on kidney transplant.

CONCLUSIONS

This review contextualizes the quality of the data, identifies seminal work by organ, and reports gaps in the literature where future research on disparities in organ transplantation should focus. Future work should investigate the association of social determinants of health with access to the organ transplant waiting list, with a focus on prospective analyses that assess interventions to improve health equity.

Graft Survival and Segment Discards Among Split-Liver and Reduced-Size Transplantations in the United States From 2008 to 2018

Split-liver transplantation has allocation advantages over reduced-size transplantation because of its ability to benefit 2 recipients. However, prioritization of split-liver transplantation relies on the following 3 major assumptions that have never been tested in the United States: similar long-term transplant recipient outcomes, lower incidence of segment discard among split-liver procurements, and discard of segments among reduced-size procurements that would be otherwise "transplantable." We used United Network for Organ Sharing Standard Transplant Analysis and Research data to identify all split-liver (n = 1831) and reduced-size (n = 578) transplantation episodes in the United States between 2008 and 2018. Multivariable Cox proportional hazards modeling was used to compare 7-year all-cause graft loss between cohorts. Secondary analyses included etiology of 30-day all-cause graft loss events as well as the incidence and anatomy of discarded segments. We found no difference in 7-year all-cause graft loss (adjusted hazard ratio [aHR], 1.1; 95% confidence interval [CI], 0.8-1.5) or 30-day all-cause graft loss (aHR, 1.1; 95% CI, 0.7-1.8) between split-liver and reduced-size cohorts. Vascular thrombosis was the most common etiology of 30-day all-cause graft loss for both cohorts (56.4% versus 61.8% of 30-day graft losses; P = 0.85). Finally, reduced-size transplantation was associated with a significantly higher incidence of segment discard (50.0% versus 8.7%) that were overwhelmingly right-sided liver segments (93.6% versus 30.3%). Our results support the prioritization of split-liver over reduced-size transplantation whenever technically feasible.

MELD 3.0: The Model for End-Stage Liver Disease Updated for the Modern Era

BACKGROUND & AIMS

The Model for End-Stage Liver Disease (MELD) has been established as a reliable indicator of short-term survival in patients with end-stage liver disease. The current version (MELDNa), consisting of the international normalized ratio and serum bilirubin, creatinine, and sodium, has been used to determine organ allocation priorities for liver transplantation in the United States. The objective was to optimize MELD further by taking into account additional variables and updating coefficients with contemporary data.

METHODS

All candidates registered on the liver transplant wait list in the US national registry from January 2016 through December 2018 were included. Uni- and multivariable Cox models were developed to predict survival up to 90 days after wait list registration. Model fit was tested using the concordance statistic (C-statistic) and reclassification, and the Liver Simulated Allocation Model was used to estimate the impact of replacing MELDNa with the new model.

RESULTS

The final multivariable model was characterized by (1) additional variables of female sex and serum albumin, (2) interactions between bilirubin and sodium and between albumin and creatinine, and (3) an upper bound for creatinine at 3.0 mg/dL. The final model (MELD 3.0) had better discrimination than MELDNa (C-statistic, 0.869 vs 0.862; P < .01). Importantly, MELD 3.0 correctly reclassified a net of 8.8% of decedents to a higher MELD tier, affording them a meaningfully higher chance of transplantation, particularly in women. In the Liver Simulated Allocation Model analysis, MELD 3.0 resulted in fewer wait list deaths compared to MELDNa (7788 vs 7850; P = .02).

CONCLUSION

MELD 3.0 affords more accurate mortality prediction in general than MELDNa and addresses determinants of wait list outcomes, including the sex disparity.

Correcting the sex disparity in MELD-Na

MELD-Na appears to disadvantage women awaiting liver transplant by underestimating their mortality rate. Fixing this problem involves: (1) estimating the magnitude of this disadvantage separately for each MELD-Na, (2) designing a correction for each MELD-Na, and (3) evaluating corrections to MELD-Na using simulated allocation. Using Kaplan-Meier modeling, we calculated 90-day without-transplant survival for men and women, separately at each MELD-Na. For most scores between 15 and 35, without-transplant survival was higher for men by 0-5 percentage points. We tested two proposed corrections to MELD-Na (MELD-Na-MDRD and MELD-GRAIL-Na), and one correction we developed (MELD-Na-Shift) to target the differences we quantified in survival across the MELD-Na spectrum. In terms of without-transplant survival, MELD-Na-MDRD overcorrected sex differences while MELD-GRAIL-Na and MELD-Na-Shift eliminated them. Estimating the impact of implementing these corrections with the liver simulated allocation model, we found that MELD-Na-Shift alone eliminated sex disparity in transplant rates (p = 0.4044) and mortality rates (p = 0.7070); transplant rates and mortality rates were overcorrected by MELD-Na-MDRD (p = 0.0025, p = 0.0006) and MELD-GRAIL-Na (p = 0.0079, p = 0.0005). We designed a corrected MELD-Na that eliminates sex disparities in without-transplant survival, but allocation changes directing smaller livers to shorter candidates may also be needed to equalize women's access to liver transplant.

Gender disparities in transplantation

PURPOSE OF REVIEW

Transplantation is the life-saving therapy for patients suffering from end-organ failure, and as such, equitable access to transplantation (ATT) is of paramount importance. Unfortunately, gender/sex-based disparities exist, and despite the transplant community's awareness of this injustice, gender/sex-based disparities have persisted for more than two decades. Importantly, no legislation or allocation policy has addressed inequity in ATT that women disproportionately face. In fact, introduction of the model for end-stage liver disease-based liver allocation system in 2002 widened the gender disparity gap and it continues to be in effect today. Moreover, women suffering from kidney disease are consistently less likely to be referred for transplant evaluation and subsequently less likely to achieve a kidney transplant, yet they comprise the majority of living kidney donors.

RECENT FINDINGS

Acknowledging gender/sex-based disparities in ATT is the first step toward interventions aimed at mitigating this long-standing injustice in healthcare.

SUMMARY

This article provides a background of end-stage liver and kidney disease in women, summarizes the existing literature describing the issue of gender disparity in ATT, and identifies potential areas of intervention and future investigation.

Sarco-Model: A score to predict the dropout risk in the perspective of organ allocation in patients awaiting liver transplantation

BACKGROUND & AIMS

Sarcopenia in liver transplantation (LT) cirrhotic candidates has been connected with higher dropouts and graft losses after transplant. The study aims to create an 'urgency' model combining sarcopenia and Model for End-stage Liver Disease Sodium (MELDNa) to predict the risk of dropout and identify an appropriate threshold of post-LT futility.

METHODS

A total of 1087 adult cirrhotic patients were listed for a first LT during January 2012 to December 2018. The study population was split into a training (n = 855) and a validation set (n = 232).

RESULTS

Using a competing-risk analysis of cause-specific hazards, we created the Sarco-Model2 . According to the model, one extra point of MELDNa was added for each 0.5 cm2 /m2 reduction of total psoas area (TPA) < 6.0 cm2 /m2 . At external validation, the Sarco-Model2 showed the best diagnostic ability for predicting the risk of 3-month dropout in patients with MELDNa < 20 (area under the curve [AUC] = 0.93; P = .003). Using the net reclassification improvement, 14.3% of dropped-out patients were correctly reclassified using the Sarco-Model2 . As for the futility threshold, transplanted patients with TPA < 6.0 cm2 /m2 and MELDNa 35-40 (n = 16/833, 1.9%) had the worse results (6-month graft loss = 25.5%).

CONCLUSIONS

In sarcopenic patients with MELDNa < 20, the 'urgency' Sarco-Model2 should be used to prioritize the list, while MELDNa value should be preferred in patients with MELDNa ≥ 20. The Sarco-Model2 played a role in more than 30% of the cases in the investigated allocation scenario. In sarcopenic patients with a MELDNa value of 35-40, 'futile' transplantation should be considered.

Racial, Gender, and Socioeconomic Disparities in Liver Transplantation

Liver transplantation (LT) is a life-saving therapy; therefore, equitable distribution of this scarce resource is of paramount importance. We searched contemporary literature on racial, gender, and socioeconomic disparities across the LT care cascade in referral, waitlist practices, allocation, and post-LT care. We subsequently identified gaps in the literature and future research priorities. Studies found that racial and ethnic minorities (Black and Hispanic patients) have lower rates of LT referral, more advanced liver disease and hepatocellular carcinoma at diagnosis, and are less likely to undergo living donor LT (LDLT). Gender-based disparities were observed in waitlist mortality and LT allocation. Women have lower LT rates after waitlisting, with size mismatch accounting for much of the disparity. Medicaid insurance has been associated with higher rates of chronic liver disease and poor waitlist outcomes. After LT, some studies found lower overall survival among Black compared with White recipients. Studies have also shown lower literacy and limited educational attainment were associated with increased posttransplant complications and lower use of digital technology. However, there are notable gaps in the literature on disparities in LT. Detailed population-based estimates of the advanced liver disease burden and LT referral and evaluation practices, including for LDLT, are lacking. Similarly, little is known about LT disparities worldwide. Evidence-based strategies to improve access to care and reduce disparities have not been comprehensively identified. Prospective registries and alternative "real-world" databases can provide more detailed information on disease burden and clinical practices. Modeling and simulation studies can identify ways to reduce gender disparities attributed to size or inaccurate estimation of renal function. Mixed-methods studies and clinical trials should be conducted to reduce care disparities across the transplant continuum.

Early Kidney Allograft Failure After Simultaneous Liver-kidney Transplantation: Evidence for Utilization of the Safety Net?

BACKGROUND

With the implementation of the "Safety Net," we aimed to determine the impact of simultaneous liver-kidney transplantation (SLKT), as compared to kidney transplant after liver transplant (KALT), on kidney allograft failure (KF).

METHODS

An analysis of the UNOS database for all adult patients who received either an SLKT or KALT from 2002 to 2017. The outcomes were 90-day KF and 1-year KF (as reported to UNOS, at 90- and 365-day postkidney transplant, respectively). We compared the following groups of patients: SLKT <25 (SLKT with final model for end-stage liver disease [MELD] <25), SLKT25/35 (MELD ≥25/<35), and SLKT35 (MELD ≥35) to KALT.

RESULTS

Of the 6276 patients, there were 1481 KALT, 1579 SLKT <25, 1832 SLKT25/35, and 1384 SLKT ≥35. The proportion of patients with 90-day and 1-year KF increased significantly among the KALT, SLKT <25, SLKT25/35, and SLKT ≥35 groups (P < 0.001; test for trend): 90-day KF: 3.3% versus 5.5% versus 7.3% versus 9.3% and 1-year KF: 5.1% versus 9.4% versus 12.3% versus 14.7%. After adjustment and compared with KALT, beginning at an MELD ≥25 those undergoing SLKT had significantly higher risk of 90-day and 1-year KF: 90-day KF: SLKT25/35: hazard ratio, 1.6(1.0-2.3); SLKT ≥35: 2.1(1.3-3.3); 1-year KF: SLKT25/35: hazard ratio, 1.7(1.2-2.4); SLKT ≥35: 2.1(1.5-3.0).

CONCLUSIONS

As compared to KALT recipients, SLKT recipients with an MELD ≥25 had significantly higher risk of early KF. Given the now well-established "Safety Net," KALT may serve as an opportunity to improve kidney outcomes in patients with an MELD ≥25.

A Review of the Current State of Liver Transplantation Disparities

Equity in access is one of the core goals of the Organ Procurement and Transplant Network (OPTN). However, disparities in liver transplantation have been described since the passage of the National Organ Transplant Act, which established OPTN in the 1980s. During the past few decades, several efforts have been made by the United Network for Organ Sharing (UNOS) to address disparities in liver transplantation with notable improvements in many areas. Nonetheless, disparities have persisted across insurance type, sex, race/ethnicity, geographic area, and age. African Americans have lower rates of referral to transplant centers, females have lower rates of transplantation from the liver waiting list than males, and public insurance is associated with worse posttransplant outcomes than private insurance. In addition, pediatric candidates and older adults have a disadvantage on the liver transplant waiting list, and there are widespread regional disparities in transplantation. Given the large degree of inequity in liver transplantation, there is a tremendous need for studies to propose and model policy changes that may make the liver transplant system more just and equitable.

Sex disparities in waitlisting and liver transplant for acute liver failure

BACKGROUND & AIMS

Sex disparities in liver transplantation (LT) for chronic liver disease have been described. It is unclear if similar disparities exist for acute liver failure (ALF).

METHODS

Adults waitlisted for LT from 2002 to 2016 with ALF were investigated using the United Network of Organ Sharing database. Clinical characteristics and causative aetiologies were compared between men and women who were waitlisted Status-1. Differences in LT, waitlist removal, and 1-year post-transplant survival were explored.

RESULTS

Of 8,408 patients waitlisted for LT with ALF, 41.3% of men and 63.9% of women were waitlisted Status-1 (p <0.001). Women had significantly higher international normalised ratio, higher frequency of grade 3-4 hepatic encephalopathy, and different aetiologies of ALF than men. On univariable analysis, women were less likely to undergo LT (subdistribution hazard ratio [SHR] 0.90; 95% CI 0.84-0.97) and were more likely to die or be removed from the waitlist as a result of clinical deterioration (SHR 1.14; 95% CI 1.002-1.30) than men. The disparities in LT (HR 0.95; 95% CI 0.87-1.03) and death/clinical deterioration (SHR 1.13; 95% CI 0.99-1.29) were no longer significant on multivariable analysis. On multivariable analysis, there was no difference in 1-year post-transplant survival between men and women.

CONCLUSIONS

Women with ALF are more likely to be waitlisted Status-1 than men. There were no clear disparities in LT or waitlist removal. Sex differences in LT and waitlist removal were attenuated on fully adjusted models, suggesting that these disparities may in part be mitigated by Status-1 listing.

LAY SUMMARY

Women with acute liver failure appear to be sicker than men and more often require urgent Status-1 waitlisting. There were no sex disparities in waitlist removal because of clinical deterioration or liver transplantation. This is in contrast to chronic liver disease, where sex disparities exist. The Status-1 waitlisting that women with acute liver failure receive may in part mitigate sex disparities in liver transplantation.

Hospitalized Women With Cirrhosis Have More Nonhepatic Comorbidities and Associated Complications Than Men

Gender differences in the natural history of chronic liver disease have been well-described. Women have lower rates of chronic liver disease and slower fibrosis progression, yet higher rates of waitlist mortality.^1,2 Although previous studies have identified several clinical factors including height and creatinine that explain some of this transplant disparity, most have used data from administrative records, which are limited in their ability to identify clinically relevant differences and opportunities for intervention to reduce disparities.^3-5 Additionally, most studies have focused on the period between waitlist and transplant, failing to capture gender differences in access to transplant.^3,6 In the present study, we took advantage of a multicenter inpatient cohort with granular clinical data to characterize how women and men with cirrhosis differ, to stimulate future research aimed at reducing the well-established gender disparity in liver transplantation.

Liver-related mortality is similar among men and women with cirrhosis

BACKGROUND & AIMS

Sex-based differences are known to significantly contribute to outcomes in patients with chronic liver diseases; however, the role of patient sex in cirrhosis is unclear. We aimed to study the relationship between patient sex and cirrhosis.

METHODS

We analyzed a cohort of 20,045 patients with cirrhosis using a Chicago-wide electronic health record database that was linked with the United Network for Organ Sharing and cause of death data from the state death registry. Adjusted Cox survival analyses and competing risk analyses were performed to obtain subdistribution hazard ratios (HRs) for liver-related cause of death.

RESULTS

Female and male patients had similar age, racial distribution, insurance status, and comorbidity status by Elixhauser score. Females had higher rates of cholestatic liver disease (17.1% vs. 6.2%, p <0.001) and non-alcoholic steatohepatitis (29.8% vs. 21.2%, p <0.001) than males. They were less likely to have portal hypertensive complications and had lower peak MELD-Na scores during follow-up. Female sex was associated with a decreased hazard of all-cause mortality (adjusted HR 0.85; 95% CI 0.80-0.90). This effect was attenuated when liver-related mortality was examined (subdistribution HR 0.93; 95% CI 0.87-1.00). No significant difference was noted for women who were 'ever-listed' in competing risk analyses for either all-cause mortality (subdistribution HR 1.09; 95% CI 0.88-1.35) or liver-related death (subdistribution HR 1.12; 95% CI 0.87-1.43), despite lower rates of listing (7.5% vs. 9.8%; p <0.001) and transplant (3.5% vs. 5.2%; p <0.001).

CONCLUSIONS

In this longitudinal study of patients with cirrhosis, female sex was associated with a survival advantage likely driven by lower rates of non-liver-related death. Women were not at an increased risk of liver-related death despite lower rates of listing and transplantation.

LAY SUMMARY

Patient sex is an important contributor in many chronic diseases, including cirrhosis. Prior studies have suggested that female sex is associated with worse outcomes. We analyzed a cohort of 20,045 patients with cirrhosis using a Chicago-wide electronic health record database. Using multivariate competing risk analyses, we found that female sex in cirrhosis is actually associated with a lower risk of all-cause mortality and has no association with liver-related mortality. Our findings are novel because we show that women with cirrhosis have a similar risk of liver-related death as their male counterparts, despite lower rates of listing and transplantation.

Comparison of Wait-List Mortality Between Cholangiocarcinoma and Hepatocellular Carcinoma Liver Transplant Candidates

Despite the divergent disease biology of cholangiocarcinoma (CCA) and hepatocellular carcinoma (HCC), wait-list prioritization is identical for both diagnoses. We compared wait-list and posttransplant outcomes between CCA and HCC liver transplantation patients with Model for End-Stage Liver Disease exceptions using Scientific Registry of Transplant Recipients data. The 408 CCA candidates listed between 2003 and mid-2017 were matched to 2 HCC cohorts by listing date (±2 months, n = 816) and by Organ Procurement and Transplantation Network (OPTN) region and date (±6 months, n = 408). Cumulative incidence competing risk regression examined the effects of diagnosis, OPTN region, and center-level CCA listing volume on wait-list removal due to death/being too ill (dropout). Cox models evaluated the effects of diagnosis, OPTN region, center-level CCA volume, and waiting time on graft failure among deceased donor liver transplantation (DDLT) recipients. After adjusting for OPTN region and CCA listing volume (all P ≥ 0.07), both HCC cohorts had a reduced likelihood of wait-list dropout compared with CCA candidates (HCC with period matching only: subdistribution hazard ratio [SHR] = 0.63; 95% CI, 0.43-0.93; P = 0.02 and HCC with OPTN region and period matching: SHR = 0.60; 95% CI, 0.41-0.87; P = 0.007). The cumulative incidence rates of wait-list dropout at 6 and 12 months were 13.2% (95% CI, 10.0%-17.0%) and 23.9% (95% CI, 20.0%-29.0%) for CCA candidates, 7.3% (95% CI, 5.0%-10.0%) and 12.7% (95% CI, 10.0%-17.0%) for HCC candidates with region and listing date matching, and 7.1% (95% CI, 5.0%-9.0%) and 12.6% (95% CI, 10.0%-15.0%) for HCC candidates with listing date matching only. Additionally, HCC DDLT recipients had a 57% reduced risk of graft failure compared with CCA recipients (P < 0.001). Waiting time was unrelated to graft failure (P = 0.57), and there was no waiting time by diagnosis cohort interaction effect (P = 0.47). When identically prioritized, LT candidates with CCA have increased wait-list dropout compared with those with HCC. More granular data are necessary to discern ways to mitigate this wait-list disadvantage and improve survival for patients with CCA.

The trials and tribulations of liver allocation

Allocation policies are necessary to ensure a fair distribution of a scarce resource. The goal of any liver transplant allocation policy is to achieve the best possible outcomes for the waiting list population, irrespective of the indication for transplant, whilst maximizing organ utilization. Organ allocation for liver transplantation has evolved from simple centre-based approaches driven by local issues, to complex, evidence-based algorithm prioritizing according to need. Despite the rapid evolution of allocation policies, there remain a number of challenges and new approaches are required to ensure transparency and equity on the decision-making process and the best possible outcomes for patients on the waiting list. New ways of modelling, together with novel outcome criteria, will be required to enable a dynamic adaptability of the allocation policies to the ever changing demographics of the donor population and the changing landscape of indications for transplantation.