The fundamentals of sex-based disparity in liver transplantation: Understanding can lead to change

Inconsistent values and algorithmic fairness: a review of organ allocation priority systems in the United States

BACKGROUND

The Organ Procurement and Transplant Network (OPTN) Final Rule guides national organ transplantation policies, mandating equitable organ allocation and organ-specific priority stratification systems. Current allocation scores rely on mortality predictions.

METHODS

We examined the alignment between the ethical priorities across organ prioritization systems and the statistical design of the risk models in question. We searched PubMed for literature on organ allocation history, policy, and ethics in the United States.

RESULTS

We identified 127 relevant articles, covering kidney (19), liver (60), lung (24), and heart transplants (23), and transplant accessibility (1). Current risk scores emphasize model performance and overlook ethical concerns in variable selection. The inclusion of race, sex, and geographical limits as categorical variables lacks biological basis; therefore, blurring the line between evidence-based models and discrimination. Comprehensive ethical and equity evaluation of risk scores is lacking, with only limited discussion of the algorithmic fairness of the Model for End-Stage Liver Disease (MELD) and the Kidney Donor Risk Index (KDRI) in some literature. We uncovered the inconsistent ethical standards underlying organ allocation scores in the United States. Specifically, we highlighted the exception points in MELD, the inclusion of race in KDRI, the geographical limit in the Lung Allocation Score, and the inadequacy of risk stratification in the Heart Tier system, creating obstacles for medically underserved populations.

CONCLUSIONS

We encourage efforts to address statistical and ethical concerns in organ allocation models and urge standardization and transparency in policy development to ensure fairness, equitability, and evidence-based risk predictions.

Sex disparities in acute-on-chronic liver failure: From admission to the intensive care unit to liver transplantation

Acute-on-chronic liver failure (ACLF) is a severe clinical syndrome characterized by acute liver decompensation in patients with chronic liver disease, marked by systemic inflammation and systemic organ failure. In this review, we discussed sex-related disparities in the incidence, prognosis, and access to liver transplantation (LT) for patients with ACLF, particularly during Intensive Care Unit (ICU) management. Some studies have suggested that ACLF is more prevalent among male patients admitted to the ICU, and they have higher mortality rates than females. Available prognostic scores, such as CLIF-C or TAM-score, lack sex-specific adjustments. Sarcopenia seems to enhance the accuracy of these scores though this is observed only in male individuals. LT is the only effective treatment for patients with ACLF grade 2-3 who do not respond to medical therapies. Sex-related disparities occur in both access to LT and post-transplant outcomes, although the influence of sex on the prevalence, clinical course, and listing for LT in ACLF remains largely undetermined. A sex-orientated analysis of ICU outcomes in ACLF would facilitate the development of sex-orientated management strategies, thereby improving patients' outcomes.

Demographic inequities exist and influence transplant outcomes in liver transplantation for acute alcohol-associated hepatitis

BACKGROUND

Liver transplantation has inherent disparities but data is scarce in liver transplant (LT) candidates with acute alcohol-associated hepatitis (AAH). We aimed to investigate demographic inequities and its impact on survival outcomes among AAH LT candidates.

METHODS

A retrospective analysis using the United Network of Organ Sharing database was conducted between 2000 and 2021. 25 981 LT recipients with alcohol-associated liver cirrhosis and 662 recipients with AAH were included. Waitlisted candidates were also evaluated.

RESULTS

In comparison with alcohol-associated liver cirrhosis, AAH LT recipients were more likely Asian or "other" race and younger. Hispanics demonstrated better graft and patient survival (p < 0.05) but were less likely to be waitlisted and transplanted for AAH than for liver cirrhosis. Women with AAH were more likely to be waitlisted and transplanted. Pre-existing diabetes and male sex were associated with higher graft failure (25% and 8% respectively). Increasing recipient age were 2% more likely to experience negative outcomes. Chronicity of liver disease did not impact graft (p = 0.137) or patient survival (p = 0.145).

CONCLUSION

Our results revealed demographic factors have a significant impact on transplant listing, organ allocation and survival outcomes. Further investigations are imperative to minimize disparities in LT evaluation and provide equity in healthcare.

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.

Addressing sex-based disparities in liver transplantation

PURPOSE OF REVIEW

Disparities in access to liver transplantation by sex have been well described, disadvantaging women. Understanding the multifactorial causes of these disparities as well as the variety of proposed solutions is critical to improving access to this life-saving intervention for women. This review aims to summarize the current body of evidence on observed sex disparities in liver transplantation and highlight actionable, evidence-based mechanisms by which these disparities can be addressed.

RECENT FINDINGS

Strategies for addressing sex disparities in liver transplantation include increasing organ utilization, changing allocation policy, and leveraging public policies to reduce the incidence of end-stage liver disease. Several other promising interventions are currently being explored.

SUMMARY

In the United States, women face additional barriers to liver transplantation on the basis of sex. Immediate action is necessary to systematically address these inequities.

Addressing sex-based disparities in solid organ transplantation in the United States - a conference report

Solid organ transplantation provides the best treatment for end-stage organ failure, but significant sex-based disparities in transplant access exist. On June 25, 2021, a virtual multidisciplinary conference was convened to address sex-based disparities in transplantation. Common themes contributing to sex-based disparities were noted across kidney, liver, heart, and lung transplantation, specifically the existence of barriers to referral and wait listing for women, the pitfalls of using serum creatinine, the issue of donor/recipient size mismatch, approaches to frailty and a higher prevalence of allosensitization among women. In addition, actionable solutions to improve access to transplantation were identified, including alterations to the current allocation system, surgical interventions on donor organs, and the incorporation of objective frailty metrics into the evaluation process. Key knowledge gaps and high-priority areas for future investigation were also discussed.