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

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.

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.

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.

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12939-021-01616-x.

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.

Women who undergo liver transplant have longer length of stay post-transplant compared with men

BACKGROUND

Women on the liver transplant waitlist are at greater risk of hospitalization compared with men, but whether this impacts length of stay (LOS) post-transplant is unknown. We aimed to evaluate gender disparities in post-transplant LOS, an important surrogate of health resource utilization post-transplant.

METHODS

Using the UNOS/OPTN registry, we analysed all non-Status 1 adult deceased donor liver transplant recipients without exception points from 2008 to 2017. Poisson regression associated female gender with post-transplant LOS.

RESULTS

Of 27 294 transplant recipients, 36% were women. Women were more likely to be hospitalized pretransplant than men (44% vs 39%, P < .01). Post-transplant, women were more likely to have prolonged (≥20d) LOS (25% vs 22%, P < .01). In univariable analysis, female gender was associated with longer post-transplant LOS (IRR 1.09, 95%CI 1.06-1.12, P < .01). Prolonged pretransplant admission was also associated with post-transplant LOS (IRR 1.83, 95%CI 1.77-1.89, P < .01). In multivariable analysis, female gender remained independently associated with post-transplant LOS (aIRR 1.05, 95%CI 1.02-1.08, P < .01), after adjustment for age, UNOS region, insurance type, MELDNa, cirrhosis complications, and donor risk index. Pretransplant hospitalization mediated this relationship, explaining 14.1% (95%CI 9.7%-25.4%) of the total effect.

CONCLUSIONS

Women who undergo deceased donor liver transplant have increased healthcare utilization in the peritransplant period compared with men. Reducing gender disparities in liver transplantation, including the disproportionate burden of healthcare utilization by women pre- and post-transplant, will require interventions targeted at preventing hospitalization among women on the transplant waitlist and developing tools aimed at better characterizing the severity of end-stage liver disease in women.

Sex and Gender Disparities in Pretransplant Characteristics and Relationships with Postoperative Outcomes in Liver Transplant Recipients with Alcoholic Liver Disease

OBJECTIVES

Previous studies of liver transplant recipients have reported discrepancies with regard to gender and/or sex differences but have focused on pretransplant outcomes. Female candidates are less likely to receive liver transplant and more likely to die or be delisted than their male counterparts. Here, we examined differences in men versus women with alcoholic liver disease before liver transplant and the effects of these differences on posttransplant survival.

MATERIALS AND METHODS

We analyzed the Scientific Registry of Transplant Recipients records of adult, deceased-donor, whole liver transplant recipients with decompensated alcoholic liver disease from 2002 to 2017 to evaluate the effects of gender on survival in 2 alcoholic liver disease cohorts: (a) including and (b) excluding recipients with additional diagnoses. Pretransplant characteristics were compared using chi-square or t tests. Kaplan-Meier and multivariable proportional hazards regression models were used to evaluate the main and covariable-adjusted effects of gender on survival.

RESULTS

Of 13781 transplant recipients with decompensated end-stage liver disease, as defined by Model for End-Stage Liver Disease score ≥ 15, 10924 (79%) were men and 2857 (21%) were women. Women had higher Model for End-Stage Liver Disease scores, higher rates of stage 4 and 5 chronic kidney disease, and were more likely to be on dialysis or ventilator support at time of transplant (all P < .05). Among all recipients, and after adjusting for risk factors, men were approximately 9% more likely than women to experience long-term graft loss (hazard ratio = 1.093; 95% confidence interval, 1.00-1.19; P = .043). However, sex difference was not associated with risk of graft loss among those without additional diagnoses (hazard ratio = 1.09; 95% confidence interval, 0.99-1.21; P = .095).

CONCLUSIONS

Although women with alcoholic liver disease who undergo liver transplant have higher severity of illness than their male counterparts, long-term outcomes are comparable.

Equally Interchangeable? How Sex and Gender Affect Transplantation

Organ transplantation as an option to overcome end-stage diseases is common in countries with advanced healthcare systems and is increasingly provided in emerging and developing countries. A review of the literature points to sex- and gender-based inequity in the field with differences reported at each step of the transplant process, including access to a transplantation waiting list, access to transplantation once waitlisted, as well as outcome after transplantation. In this review, we summarize the data regarding sex- and gender-based disparity in adult and pediatric kidney, liver, lung, heart, and hematopoietic stem cell transplantation and argue that there are not only biological but also psychological and socioeconomic issues that contribute to disparity in the outcome, as well as an inequitable access to transplantation for women and girls. Because the demand for organs has always exceeded the supply, the transplant community has long recognized the need to ensure equity and efficiency of the organ allocation system. In the spirit of equity and equality, the authors call for recognition of these inequities and the development of policies that have the potential to ensure that girls and women have equitable access to transplantation.

MELD-GRAIL-Na: Glomerular Filtration Rate and Mortality on Liver-Transplant Waiting List

BACKGROUND AND AIMS

Among patients with cirrhosis awaiting liver transplantation, prediction of wait-list (WL) mortality is adjudicated by the Model for End Stage Liver Disease-Sodium (MELD-Na) score. Replacing serum creatinine (SCr) with estimated glomerular filtration rate (eGFR) in the MELD-Na score may improve prediction of WL mortality, especially for women and highest disease severity.

APPROACH AND RESULTS

We developed (2014) and validated (2015) a model incorporating eGFR using national data (n = 17,095) to predict WL mortality. Glomerular filtration rate (GFR) was estimated using the GFR assessment in liver disease (GRAIL) developed among patients with cirrhosis. Multivariate Cox proportional hazard analysis models were used to compare the predicted 90-day WL mortality between MELD-GRAIL-Na (re-estimated bilirubin, international normalized ratio [INR], sodium, and GRAIL) versus MELD-Na. Within 3 months, 27.8% were transplanted, 4.3% died on the WL, and 4.7% were delisted for other reasons. GFR as estimated by GRAIL (hazard ratio [HR] 0.382, 95% confidence interval [CI] 0.344-0.424) and the re-estimated model MELD-GRAIL-Na (HR 1.212, 95% CI 1.199-1.224) were significant predictors of mortality or being delisted on the WL within 3 months. MELD-GRAIL-Na was a better predictor of observed mortality at highest deciles of disease severity (≥ 27-40). For a score of 32 or higher (observed mortality 0.68), predicted mortality was 0.67 (MELD-GRAIL-Na) and 0.51 (MELD-Na). For women, a score of 32 or higher (observed mortality 0.67), the predicted mortality was 0.69 (MELD-GRAIL-Na) and 0.55 (MELD-Na). In 2015, use of MELD-GRAIL-Na as compared with MELD-Na resulted in reclassification of 16.7% (n = 672) of patients on the WL.

CONCLUSION

Incorporation of eGFR likely captures true GFR better than SCr, especially among women. Incorporation of MELD-GRAIL-Na instead of MELD-Na may affect outcomes for 12%-17% awaiting transplant and affect organ allocation.

Chronic Kidney Disease in Liver Transplant Candidates: A Rising Burden Impacting Post-Liver Transplant Outcomes

The burden of chronic kidney disease (CKD) is rising among patients with cirrhosis, though it is not known what impact this has had on outcomes after liver transplantation (LT). All patients listed for LT in the United States between 2002 and 2017 were analyzed, excluding those listed with Model for End-Stage Liver Disease (MELD) exceptions. The primary outcome was post-LT mortality. We defined pre-LT CKD as an estimated glomerular filtration rate <60 mL/minute for 90 days or ≥42 days of hemodialysis. Cox regression determined the association between pre-LT CKD and post-LT mortality. Of 78,640 LT candidates, the proportion with CKD among LT recipients increased from 7.8% in 2002 to 14.6% in 2017 (test for trend, P < 0.001). Among the 39,719 LT recipients, pre-LT CKD was significantly associated with post-LT mortality (hazard ratio [HR], 1.16; P < 0.001) even after adjusting for donor risk index (DRI), age, MELD, etiology, hepatic encephalopathy, simultaneous liver-kidney transplantation (SLKT), and diabetes. There was no mediating influence of SLKT on the effect of pre-LT CKD on post-LT survival (P > 0.05). Therefore, pre-LT CKD has a deleterious impact on post-LT outcomes, which is an impact that is not mediated through SLKT. These findings highlight the need for the identification of CKD when preventative measures are possible.

Split liver transplantation is utilized infrequently and concentrated at few transplant centers in the United States

Split liver transplantation (SLT) is 1 strategy for maximizing the number of deceased donor liver transplants. Recent reports suggest that utilization of SLT in the United States remains low. We examined deceased donor offers that were ultimately split between 2010 and 2014. SLTs were categorized as "primary" and "secondary" transplants. We analyzed allocation patterns and used logistic regression to evaluate factors associated with secondary split discard. Four hundred eighteen livers were split: 54% from adult, 46% from pediatric donors. Of the 227 adult donor livers split, 61% met United Network for Organ Sharing "optimal" split criteria. A total of 770 recipients (418 primary and 352 secondary) were transplanted, indicating 16% discard. Ninety-two percent of the 418 primary recipients were children, and 47% were accepted on the first offer. Eighty-seven percent of the 352 secondary recipients were adults, and 7% were accepted on the first offer. Of the 352 pairs, 99% were transplanted in the same region, 36% at the same center. In logistic regression, shorter donor height was associated with secondary discard (odds ratio 0.97 per cm, 95% CI 0.94-1.00, P = .02). SLT volume by center was not predictive of secondary discard. Current policy proposals that incentivize SLT in the United States could increase the number of transplants to children and adults.

Identifying a clinically relevant cutoff for height that is associated with a higher risk of waitlist mortality in liver transplant candidates

Height explains a substantial proportion of gender-based disparity in waitlist mortality among liver transplant candidates. We sought to identify a clinically relevant height cutoff below which waitlist mortality increases significantly. We examined all nonstatus one adult liver transplant candidates from 2010 to 2014. We used a recursive application of the minimum P value approach with univariate competing risk regressions (deceased donor liver transplantation as the competing risk) to detect differences in waitlist mortality with regards to height. Of 69 883 candidates, 36% (24 819) were women and 64% (45 064) were men. Median height for all was 173 cm: 163 cm in women, 178 cm in men. The optimal search method of recursively evaluating smaller height intervals yielded 166 cm as the optimal height cutoff. Using height <166 cm as the cutoff, 72% of women and 9% of men met criteria. Compared to candidates ≥166 cm, "short stature" candidates had higher rates of death/delisting (28% vs 24%) and lower rates of transplantation (38% vs 44%) (P < .01 for both). After adjustment for clinical and demographic characteristics, height <166 cm remained associated with an 8% increased risk of waitlist mortality (95% CI 1.03-1.14, P < .01). Short candidate height may be a motivation to explore split livers or living donors as accelerated liver transplantation options.

Gender Differences Among Patients Hospitalized With Cirrhosis in the United States

BACKGROUND AND AIMS

Gender disparities exist in outcomes among patients with cirrhosis. We sought to evaluate the role of gender on hospital course and in-hospital outcomes in patients with cirrhosis to help better understand these disparities.

STUDY

We analyzed data from the National Inpatient Sample (NIS), years 2009 to 2013, to identify patients with any diagnosis of cirrhosis. We calculated demographic and clinical characteristics by gender, as well as cirrhosis complications. Our primary outcome was inpatient mortality. We used logistic regression to associate baseline characteristics and cirrhosis complications with inpatient mortality.

RESULTS

Our cohort included 553,017 patients with cirrhosis admitted from 2009 to 2013. Women made up 39% of the cohort; median age was 57 with 66% non-Hispanic white. Women were more likely than men to have noncirrhosis comorbidities, including diabetes and hypertension but were less likely to have most cirrhosis complications, including ascites and variceal bleeding. Women were more likely than men to have acute bacterial infections (34.9% vs. 28.2%; P<0.001), and were less likely than men to die in the hospital on univariable (odds ratio, 0.88; 95% confidence interval, 0.86-0.90; P<0.001) and multivariable (odds ratio, 0.86; 95% confidence interval, 0.83-0.88; P<0.001) analysis.

CONCLUSIONS

In patients hospitalized with cirrhosis, women have lower rates of hepatic decompensating events and higher rates of nonhepatic comorbidities and infections, resulting in lower in-hospital mortality. Understanding differences in indications for and disposition following hospitalization may help with the development of gender-specific cirrhosis management programs to improve long-term outcomes in women and men living with cirrhosis.

Changes in Simultaneous Liver-kidney Transplant Allocation Policy May Impact Postliver Transplant Outcomes

BACKGROUND

Previous simultaneous liver-kidney (SLK) transplant allocation was based on serum creatinine, a metric that disadvantaged women relative to men. A recent SLK transplant policy change uses estimated glomerular filtration rate (eGFR), which accounts for sex-based differences in creatinine.

METHODS

To understand the impact of this new policy, we analyzed nonstatus 1 adults listed for liver transplantation (LT) from May 2007 to July 2014, excluding those with exceptions. We defined patients who met the new SLK policy as having an eGFR <60 mL/min for 90 days, with a final eGFR <30 mL/min.

RESULTS

Of 40979 candidates, 1683 would have met only the new criteria (N-SLK), 2452 would have met only the old criteria (O-SLK), and 1878 would have met both criteria (B-SLK). Compared to those in the B-SLK or O-SLK groups, those in the N-SLK group were significantly more likely to be female (52% versus 36% versus 39%, P < 0.001). Cox-regression analysis demonstrated that in adjusted analysis those in the N-SLK group were significantly less likely to die postliver transplant (hazard ratio [HR], 0.0; P < 0.001). Further, in Cox regression subgroup analyses, both in women (HR 0.04; P < 0.001) and in men (HR, 0.02, P < 0.001) those in the N-SLK group who underwent liver transplant were significantly less likely to die postliver transplant, even after adjustment for confounders.

CONCLUSIONS

We anticipate that implementation of the new SLK policy will increase the proportion of women and decrease the proportion of men who are listed for SLK but may not improve posttransplant survival. Our data highlight the need for monitoring of SLK outcomes after implementation of the new policy.

Predicting chance of liver transplantation for pediatric wait-list candidates

Information about wait-list time has been reported as one of the single most frequently asked questions by individuals awaiting a transplant but data regarding wait-list time have not been processed in a useful way for pediatric candidates. To predict chance of receiving a DDLT, we identified 6471 pediatric (<18 years), non status-1A, liver-only transplant candidates between 2006 and 2017 from the SRTR. Cox regression with shared frailty for DSA level effect was used to model the association of blood type, weight, allocation PELD and MELD, and DSA with chance of DDLT. Jackknife technique was used for validation. Median (interquartile range) wait-list time was 100 (34-309) days. Non-O Blood type, higher PELD/MELD score at listing, and DSA were associated with increased chance of DDLT, while age 1-5 years and 10-18 years was associated with lower chance of DDLT (P < 0.001 for all variables). Our model accurately predicted chance of transplant (C-statistic = 0.68) and was able to predict DDLT at specific follow-up times (eg, 3 months). This model can serve as the basis for an online tool that would provide useful information for pediatric wait-list candidates.

Shorter Height Is Associated With Lower Probability of Liver Transplantation in Patients With Hepatocellular Carcinoma

BACKGROUND

The effect of height and sex on liver transplantation (LT) for hepatocellular carcinoma (HCC) remains unclear.

METHODS

Using United Network for Organ Sharing (UNOS) data, 14 844 HCC patients listed for LT from 2005 to 2015 were identified. Cumulative incidence of waitlist events (LT and dropout for death or too sick) were calculated and modeled using Fine and Gray competing risk regression.

RESULTS

Short (SWR), mid (MWR), and long (LWR) UNOS wait regions comprised 25%, 42%, and 33% of the cohort. Three-year cumulative incidence of LT was lower in shorter height patients (≤150, 151-165, and >185 cm; 70.8%, 76.7%, and 83.5%; P < 0.001) and women (78.2% versus 79.8%; P < 0.001). On multivariable analysis, shorter height (≤150, 151-165 cm, hazard ratio [HR] versus >185 cm) was associated with lower probability of LT (0.81 and 0.89; P = 0.02) and greater dropout (HR 1.99 and 1.43; P < 0.001). Female sex was not associated with LT overall, but a significant sex and wait region interaction (P = 0.006) identified lower LT probability for women in MWR (HR versus men, 0.91; P = 0.02).

CONCLUSIONS

Despite uniform HCC Model for End-Stage Liver Disease exception across height and sex, shorter patients and females in MWR have lower probability of LT. Consideration should be given to awarding additional Model for End-Stage Liver Disease exception points to these patients.