Addressing geographic disparities in liver transplantation through redistricting

Assessing LSAM's ability to account for changes in organ donation and transplant center behavior

The Liver Simulated Allocation Model (LSAM) is used to evaluate proposed organ allocation policies. Although LSAM has been shown to predict the directionality of changes in transplants and nonused organs, the magnitude is often overestimated. One reason is that policymakers and researchers using LSAM assume static levels of organ donation and center behavior because of challenges with predicting future behavior. We sought to assess the ability of LSAM to account for changes in organ donation and organ acceptance behavior using LSAM 2019. We ran 1-year simulations with the default model and then ran simulations changing donor arrival rates (ie, organ donation) and center acceptance behavior. Changing the donor arrival rate was associated with a progressive simulated increase in transplants, with corresponding simulated decreases in waitlist deaths. Changing parameters related to organ acceptance was associated with important changes in transplants, nonused organs, and waitlist deaths in the expected direction in data simulations, although to a much lesser degree than changing the donor arrival rate. Increasing the donor arrival rate was associated with a marked decrease in the travel distance of donor livers in simulations. In conclusion, we demonstrate that LSAM can account for changes in organ donation and organ acceptance in a manner aligned with historical precedent that can inform future policy analyses. As Scientific Registry of Transplant Recipients develops new simulation programs, the importance of considering changes in donation and center practice is critical to accurately estimate the impact of new allocation policies.

Association of Neighborhood Deprivation and Transplant Center Quality with Liver Transplantation Outcomes

BACKGROUND

Social determinants of health can impact the quality of liver transplantation (LT) care. We sought to assess whether the association between neighborhood deprivation and transplant outcomes can be mitigated by receiving care at high-quality transplant centers.

STUDY DESIGN

In this population-based cohort study, patients who underwent LT between 2004 and 2019 were identified in the Scientific Registry of Transplant Recipients. LT-recipient neighborhoods were identified at the county level and stratified into quintiles relative to Area Deprivation Index (ADI). Transplant center quality was based on the Scientific Registry of Transplant Recipients 5-tier ranking using standardized transplant rate ratios. Multivariable Cox regression was used to assess the relationship between ADI, hospital quality, and posttransplant survival.

RESULTS

A total of 41,333 recipients (median age, 57.0 [50.0 to 63.0] years; 27,112 [65.4%] male) met inclusion criteria. Patients residing in the most deprived areas were more likely to have nonalcoholic steatohepatitis, be Black, and travel further distances to reach a transplant center. On multivariable analysis, post-LT long-term mortality was associated with low- vs high-quality transplant centers (hazard ratio [HR] 1.19, 95% CI 1.07 to 1.32), as well as among patients residing in high- vs low-ADI neighborhoods (HR 1.25, 95% CI 1.16 to 1.34; both p ≤ 0.001). Of note, individuals residing in high- vs low-ADI neighborhoods had a higher risk of long-term mortality after treatment at a low-quality (HR 1.31, 95% CI 1.06 to 1.62, p = 0.011) vs high-quality (HR 1.12, 95% CI 0.83 to 1.52, p = 0.471) LT center.

CONCLUSIONS

LT at high-quality centers may be able to mitigate the association between posttransplant survival and neighborhood deprivation. Investments and initiatives that increase access to referrals to high-quality centers for patients residing in higher deprivation may lead to better outcomes and help mitigate disparities in LT.

The role of an integrated referral program for patients with liver disease: A network between hub and spoke centers

INTRODUCTION

Access to Liver transplantation (LT) can be affected by several barriers, resulting in delayed referral and increased risk of mortality due to complications of the underlying liver disease.

AIM

To assess the clinical characteristics and outcomes of patients with acute or chronic liver disease referred using an integrated referral program.

MATERIALS AND METHODS

An integrated referral program was developed in 1 October 2017 based on email addresses and a 24/7 telephone availability. All consecutive adult patients with liver disease referred for the first time using this referral program were prospectively collected until 1 October 2021. Characteristics and outcomes of inpatients were compared with a historical cohort of patients referred without using the integrated referral program (1 October 2015-1 October 2017). Patients were further divided according to pre- and post-Covid-19 pandemic.

RESULTS

Two hundred eighty-one referred patients were considered. End stage liver disease was the most common underlying condition (79.3%), 50.5% of patients were referred as inpatients and 74.7% were referred for LT evaluation. When inpatient referrals (n = 142) were compared with the historical cohort (n = 86), a significant increase in acute liver injury due to drugs/herbals and supplements was seen (p = 0.01) as well as an increase in End stage liver disease due to alcohol-related liver disease and NASH, although not statistically significant. A significant increase in referrals for evaluation for Trans-jugular intrahepatic portosystemic shunt placement was seen over time (5.6% vs. 1%; p = 0.01) as well as for LT evaluation (84.5% vs. 81%; p = 0.01). Transplant-free survival was similar between the study and control groups (p = 0.3). The Covid-19 pandemic did not affect trends of referrals and patient survival.

CONCLUSIONS

The development of an integrated referral program for patients with liver disease can represent the first step to standardize already existing referral networks between hub and spoke centers. Future studies should focus on the timing of referral according to different etiologies to optimize treatment options and outcomes.

A transformer-based deep learning approach for fairly predicting post-liver transplant risk factors

Liver transplantation is a life-saving procedure for patients with end-stage liver disease. There are two main challenges in liver transplant: finding the best matching patient for a donor and ensuring transplant equity among different subpopulations. The current MELD scoring system evaluates a patient's mortality risk if not receiving an organ within 90 days. However, the donor-patient matching should also consider post-transplant risk factors, such as cardiovascular disease, chronic rejection, etc., which are all common complications after transplant. Accurate prediction of these risk scores remains a significant challenge. In this study, we used predictive models to solve the above challenges. Specifically, we proposed a deep learning model to predict multiple risk factors after a liver transplant. By formulating it as a multi-task learning problem, the proposed deep neural network was trained to simultaneously predict the five post-transplant risks and achieve equal good performance by exploiting task-balancing techniques. We also proposed a novel fairness-achieving algorithm to ensure prediction fairness across different subpopulations. We used electronic health records of 160,360 liver transplant patients, including demographic information, clinical variables, and laboratory values, collected from the liver transplant records of the United States from 1987 to 2018. The model's performance was evaluated using various performance metrics such as AUROC and AUPRC. Our experiment results highlighted the success of our multi-task model in achieving task balance while maintaining accuracy. The model significantly reduced the task discrepancy by 39 %. Further application of the fairness-achieving algorithm substantially reduced fairness disparity among all sensitive attributes (gender, age group, and race/ethnicity) in each risk factor. It underlined the potency of integrating fairness considerations into the task-balancing framework, ensuring robust and fair predictions across multiple tasks and diverse demographic groups.

Removing geographic boundaries from liver allocation: A method for designing continuous distribution scores

BACKGROUND

The Organ Procurement and Transplantation Network (OPTN) is eliminating geographic boundaries in liver allocation, in favor of continuous distribution. Continuous distribution allocates organs via a composite allocation score (CAS): a weighted sum of attributes like medical urgency, candidate biology, and placement efficiency. The opportunity this change represents, to include new variables and features for prioritizing candidates, will require lengthy and contentious discussions to establish community consensus. Continuous distribution could instead be implemented rapidly by computationally translating the allocation priorities for pediatric, status 1, and O/B blood type liver candidates that are presently implemented via geographic boundaries into points and weights in a CAS.

METHODS

Using simulation with optimization, we designed a CAS that is minimally disruptive to existing prioritizations, and that eliminates geographic boundaries and minimizes waitlist deaths without harming vulnerable populations.

RESULTS

Compared with Acuity Circles (AC) in a 3-year simulation, our optimized CAS decreased deaths from 7771.2 to 7678.8 while decreasing average (272.66 NM vs. 264.30 NM) and median (201.14 NM vs. 186.49 NM) travel distances. Our CAS increased travel only for high MELD and status 1 candidates (423.24 NM vs. 298.74 NM), and reduced travel for other candidates (198.98 NM vs. 250.09 NM); overall travel burden decreased.

CONCLUSION

Our CAS reduced waitlist deaths by sending livers for high-MELD and status 1 candidates farther, while keeping livers for lower MELD candidates nearby. This advanced computational method can be applied again after wider discussions of adding new priorities conclude; our method designs score weightings to achieve any specified feasible allocation outcomes.

The trends in cost associated with liver transplantation in the US: Analysis of weighted hospital data

This study aims to evaluate recent annualized trends in the cost-burden of inpatient hospitalizations associated with liver transplantation (LT) in the US as stratified by patient demographics and medical characteristics. From 2016 to 2019 National Inpatient Sample was used to select patients who underwent LT, from which the weighted charge estimates were derived and converted to admission costs using inflation-adjusted charge-to-cost ratios. The adjusted values were stratified using select patient variables and graphed across the respective years to derive goodness-of-fit for each trend (expressed with R2 and p -values). From 2016 to 2019, the estimated total number of LT-related hospitalizations in the US were 6685, 7075, 7260, and 7815 cases respectively. There was a general increase in the total cost of LT-related hospitalizations over the years: $945.75, $1010.23, $1052.46, and $1143.84 in millions of dollars (0.98, 0.01). Furthermore, positive trends in total cost were observed in the following strata: patients aged 35-49 (0.92, 0.04) and above 65 (0.91, 0.05), Whites (0.99, 0.01), those with congestive heart failure (0.98, 0.01), ≥2 comorbidities (0.97, 0.02), hepatic encephalopathy (0.93, 0.04), and those with private insurance (0.93, 0.04), as well as LT performed in the Northeast (0.94, 0.03), Midwest (0.92, 0.04), and South (0.91, 0.04). Total cost associated with hepatitis C declined significantly (0.94, 0.03). With respect to mean costs, positive trends were observed in the following strata: those with other or cryptogenic liver disease (0.93, 0.03), ≥2 comorbidities (0.96, 0.02), and LT performed in the Northeast region (0.93, 0.04). The number of liver transplants performed in the US, as well as the associated costs, are rising. Given the apparent rising costs in specific patient populations, economic and public health policies must focus on cost containment within these groups to ensure appropriate usage of resources.

Logistical burden of offers and allocation inefficiency in circle-based liver allocation

Recent changes to liver allocation replaced donor service areas with circles as the geographic unit of allocation. Circle-based allocation might increase the number of transplantation centers and candidates required to place a liver, thereby increasing the logistical burden of making and responding to offers on organ procurement organizations and transplantation centers. Circle-based allocation might also increase distribution time and cold ischemia time (CIT), particularly in densely populated areas of the country, thereby decreasing allocation efficiency. Using Scientific Registry of Transplant Recipient data from 2019 to 2021, we evaluated the number of transplantation centers and candidates required to place livers in the precircles and postcircles eras, nationally and by donor region. Compared with the precircles era, livers were offered to more candidates (5 vs. 9; p  < 0.001) and centers (3 vs. 5; p  < 0.001) before being accepted; more centers were involved in the match run by offer number 50 (9 vs. 14; p  < 0.001); CIT increased by 0.2 h (5.9 h vs. 6.1 h; p  < 0.001); and distribution time increased by 2.0 h (30.6 h vs. 32.6 h; p  < 0.001). Increased burden varied geographically by donor region; livers recovered in Region 9 were offered to many more candidates (4 vs. 12; p  < 0.001) and centers (3 vs. 8; p  < 0.001) before being accepted, resulting in the largest increase in CIT (5.4 h vs. 6.0 h; p  < 0.001). Circle-based allocation is associated with increased logistical burdens that are geographically heterogeneous. Continuous distribution systems will have to be carefully designed to avoid exacerbating this problem.

Disparities in the Effects of Acuity Circle-based Liver Allocation on Waitlist and Transplant Practice Between Centers

Liver allocation in the United States was updated on February 4, 2020, by introducing the acuity circle (AC)–based model. This study evaluated the early effects of the AC-based allocation on waitlist outcomes.

County-level Differences in Liver-related Mortality, Waitlisting, and Liver Transplantation in the United States

BACKGROUND

Much of our understanding regarding geographic issues in transplantation is based on statistical techniques that do not formally account for geography and is based on obsolete boundaries such as donation service area.

METHODS

We applied spatial epidemiological techniques to analyze liver-related mortality and access to liver transplant services at the county level using data from the Centers for Disease Control and Prevention and Scientific Registry of Transplant Recipients from 2010 to 2018.

RESULTS

There was a significant negative spatial correlation between transplant rates and liver-related mortality at the county level (Moran's I, -0.319; P  = 0.001). Significant clusters were identified with high transplant rates and low liver-related mortality. Counties in geographic clusters with high ratios of liver transplants to liver-related deaths had more liver transplant centers within 150 nautical miles (6.7 versus 3.6 centers; P  < 0.001) compared with all other counties, as did counties in geographic clusters with high ratios of waitlist additions to liver-related deaths (8.5 versus 2.5 centers; P  < 0.001). The spatial correlation between waitlist mortality and overall liver-related mortality was positive (Moran's I, 0.060; P  = 0.001) but weaker. Several areas with high waitlist mortality had some of the lowest overall liver-related mortality in the country.

CONCLUSIONS

These data suggest that high waitlist mortality and allocation model for end-stage liver disease do not necessarily correlate with decreased access to transplant, whereas local transplant center density is associated with better access to waitlisting and transplant.

Dynamic impact of liver allocation policy change on donor utilization

Liver allocation policy was changed to reduce variance in median MELD scores at transplant (MMaT) in February 2020. "Acuity circles" replaced local allocation. Understanding the impact of policy change on donor utilization is important. Ideal (I), standard (S), and non-ideal (NI) donors were defined. NI donors include older, higher BMI donors with elevated transaminases or bilirubin, history of hepatitis B or C, and all DCD donors. Utilization of I, S, and NI donors was established before and after allocation change and compared between low MELD (LM) centers (MMaT ≤ 28 before allocation change) and high MELD (HM) centers (MMaT > 28). Following reallocation, transplant volume increased nationally (67 transplants/center/year pre, 74 post, p .0006) and increased for both HM and LM centers. LM centers significantly increased use of NI donors and HM centers significantly increased use of I and S donors. Centers further stratify based on donor utilization phenotype. A subset of centers increased transplant volume despite rising MMaT by broadening organ acceptance criteria, increasing use of all donor types including DCD donors (98% increase), increasing living donation, and transplanting more frequently for alcohol associated liver disease. Variance in donor utilization can undermine intended effects of allocation policy change.

Impact of Advanced Renal Dysfunction on Posttransplant Outcomes After Living Donor Liver Transplantation in the United States

BACKGROUND

Survival after living donor liver transplantation (LDLT) in the United States is excellent. However, the significance of pretransplant kidney disease on outcomes in this population is poorly understood.

METHODS

This was a retrospective cohort study of 2806 LDLT recipients nationally between January 2010 and June 2020. Recipients with estimated glomerular filtration rate <40 mL/min/1.73 m2 (eGFR-low) or requiring dialysis were compared. Multivariable survival analyses evaluated (1) eGFR-low as a predictor of post-LDLT survival and (2) the survival of LDLT versus deceased donor liver transplant (DDLT) alone with eGFR-low.

RESULTS

From 2010 to 2020, 140 (5.0%) patients had eGFR-low and 18 (0.6%) required dialysis pre-LDLT. The number of LDLTs requiring dialysis between 2017 and 2020 outnumbered the prior 7 y. Overall LDLT experience was greater at centers performing LDLT in recipients with renal dysfunction (P < 0.001). LDLT recipients with eGFR-low had longstanding renal dysfunction: mean eGFR 3-6 mo before LDLT 42.7 (±15.1) mL/min/1.73 m2. Nearly half (5/12) of eGFR-low recipients with active kidney transplant (KT) listing at LDLT experienced renal recovery. Five patients underwent early KT after LDLT via the new "safety net" policy. Unadjusted survival after LDLT was worse with eGFR-low (hazard ratio 2.12 versus eGFR ≥40 mL/min/1.73 m2; 95% confidence interval, 1.47-3.05; P < 0.001), but no longer so when accounting for mean eGFR 3-6 mo pre-LDLT (hazard ratio, 1.27; 95% confidence interval, 0.82-1.95; P = 0.3). The adjusted survival of patients with eGFR-low receiving LDLT versus deceased donor liver transplant alone was not different (P = 0.08).

CONCLUSIONS

Overall, outcomes after LDLT with advanced renal dysfunction are acceptable. These findings are relevant given the recent "safety net" KT policy.

Disparities in Lung Transplantation

Since the initial report of long-term survival after lung transplantation (LT) in 1983, there has been remarkable progress in the field and LT is now the gold-standard therapy for patients with end-stage lung disease. It confers a significant survival advantage and improves the quality of life in patients who often have few other treatment options. However, LT remains a complex undertaking and establishing and maintaining an LT program is resource intensive with multiple potential barriers. In this article, we focus on disparities in LT and the potential solutions to improving access to LT.

Geographic disparities in transplantation

PURPOSE OF REVIEW

The Final Rule clearly states that geography should not be a determinant of a chance of a potential candidate being transplanted. There have been multiple concerns about geographic disparities in patients in need of solid organ transplantation. Allocation policy adjustments have been designed to address these concerns, but there is little evidence that the disparities have been solved. The purpose of this review is to describe the main drivers of geographic disparities in solid organ transplantation and how allocation policy changes and other potential actions could impact these inequalities.

RECENT FINDINGS

Geographical disparities have been reported in kidney, pancreas, liver, and lung transplantation. Organ Procurement and Transplant Network has modified organ allocation rules to underplay geography as a key determinant of a candidates' chance of receiving an organ. Thus, heart, lung, and more recently liver and Kidney Allocation Systems have incorporated broader organ sharing to reduce geographical disparities. Whether these policy adjustments will indeed eliminate geographical disparities are still unclear.

SUMMARY

Modern allocation policy focus in patients need, regardless of geography. Innovative actions to further reduce geographical disparities are needed.

MELD is MELD is MELD? Transplant center-level variation in waitlist mortality for candidates with the same biological MELD

Recently, model for end-stage liver disease (MELD)-based liver allocation in the United States has been questioned based on concerns that waitlist mortality for a given biologic MELD (bMELD), calculated using laboratory values alone, might be higher at certain centers in certain locations across the country. Therefore, we aimed to quantify the center-level variation in bMELD-predicted mortality risk. Using Scientific Registry of Transplant Recipients (SRTR) data from January 2015 to December 2019, we modeled mortality risk in 33 260 adult, first-time waitlisted candidates from 120 centers using multilevel Poisson regression, adjusting for sex, and time-varying age and bMELD. We calculated a "MELD correction factor" using each center's random intercept and bMELD coefficient. A MELD correction factor of +1 means that center's candidates have a higher-than-average bMELD-predicted mortality risk equivalent to 1 bMELD point. We found that the "MELD correction factor" median (IQR) was 0.03 (-0.47, 0.52), indicating almost no center-level variation. The number of centers with "MELD correction factors" within ±0.5 points, and between ±0.5-± 1, ±1.0-±1.5, and ±1.5-±2.0 points was 62, 41, 13, and 4, respectively. No centers had waitlisted candidates with a higher-than-average bMELD-predicted mortality risk beyond ±2 bMELD points. Given that bMELD similarly predicts waitlist mortality at centers across the country, our results support continued MELD-based prioritization of waitlisted candidates irrespective of center.

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.

Liver Transplant Center Size and The Impact on the Clinical Outcomes and Resource Utilization

BACKGROUND

Prior studies suggest that transplant center volume is associated with liver transplantation (LT) outcomes. We compared patient characteristics and waitlist outcomes among transplant centers in the U.S. with different volumes.

METHODS

Data for adult waitlisted candidates and LT recipients in the U.S. between 2008 and 2017 were extracted from the Scientific Registry of Transplant Recipients database. Transplant centers were categorized by transplants/year into tertiles:low-volume centers (LVCs; <20 transplantations per year)medium-volume centers (MVCs; 20-55 transplantations per year)high-volume centers (HVCs; >55 transplantations per year)Patient characteristics, waitlist outcomes, and factors associated with post-transplantation mortality were compared.

RESULTS

From 141 centers, 112,110 patients were waitlisted for LT: 6% at LVCs, 26% at MVCs, and 68% at HVCs. Patients listed in LVCs were less likely to have private insurance but had higher Medicaid and Veterans Affairs healthcare rates. Patients at LVCs were less likely to receive LT (47% vs. 53% in MVC vs. 61% in HVC), had higher transfer rates to other centers, and were more likely to be removed from the waitlist. In competing risk survival analysis, adjusted for center location, MELD score, and clinico-demographic factors, patients listed at an HVC were more likely to receive LT (aHR:1.30; 95%CI= 1.27-1.33; P<0.001). Among LT-recipients (n=62,131), receiving a transplant at an LVC was associated with higher post-LT mortality (aHR:1.16; 95%CI=1.05-1.28; P=0.003).

CONCLUSION

Patients in LVCs were less likely to receive a LT and a higher risk of post-LT death.Supplemental Visual Abstract; http://links.lww.com/TP/C274.

Heterogeneous Circles for Liver Allocation

BACKGROUND AND AIMS

In February 2020, the Organ Procurement and Transplantation Network replaced donor service area-based allocation of livers with acuity circles, a system based on three homogeneous circles around each donor hospital. This system has been criticized for neglecting to consider varying population density and proximity to coast and national borders.

APPROACH AND RESULTS

Using Scientific Registry of Transplant Recipients data from July 2013 to June 2017, we designed heterogeneous circles to reduce both circle size and variation in liver supply/demand ratios across transplant centers. We weighted liver demand by Model for End-Stage Liver Disease (MELD)/Pediatric End-Stage Liver Disease (PELD) because higher MELD/PELD candidates are more likely to be transplanted. Transplant centers in the West had the largest circles; transplant centers in the Midwest and South had the smallest circles. Supply/demand ratios ranged from 0.471 to 0.655 livers per MELD-weighted incident candidate. Our heterogeneous circles had lower variation in supply/demand ratios than homogeneous circles of any radius between 150 and 1,000 nautical miles (nm). Homogeneous circles of 500 nm, the largest circle used in the acuity circles allocation system, had a variance in supply/demand ratios 16 times higher than our heterogeneous circles (0.0156 vs. 0.0009) and a range of supply/demand ratios 2.3 times higher than our heterogeneous circles (0.421 vs. 0.184). Our heterogeneous circles had a median (interquartile range) radius of only 326 (275-470) nm but reduced disparities in supply/demand ratios significantly by accounting for population density, national borders, and geographic variation of supply and demand.

CONCLUSIONS

Large homogeneous circles create logistical burdens on transplant centers that do not need them, whereas small homogeneous circles increase geographic disparity. Using carefully designed heterogeneous circles can reduce geographic disparity in liver supply/demand ratios compared with homogeneous circles of radius ranging from 150 to 1,000 nm.

Allocating kidneys in optimized heterogeneous circles

Recently, the Organ Procurement and Transplant Network approved a plan to allocate kidneys within 250-nm circles around donor hospitals. These homogeneous circles might not substantially reduce geographic differences in transplant rates because deceased donor kidney supply and demand differ across the country. Using Scientific Registry of Transplant Recipients data from 2016-2019, we used an integer program to design unique, heterogeneous circles with sizes between 100 and 500 nm that reduced supply/demand ratio variation across transplant centers. We weighted demand according to wait time because candidates who have waited longer have higher priority. We compared supply/demand ratios and average travel distance of kidneys, using heterogeneous circles and 250 and 500-nm fixed-distance homogeneous circles. We found that 40% of circles could be 250 nm or smaller, while reducing supply/demand ratio variation more than homogeneous circles. Supply/demand ratios across centers for heterogeneous circles ranged from 0.06 to 0.13 kidneys per wait-year, compared to 0.04 to 0.47 and 0.05 to 0.15 kidneys per wait-year for 250-nm and 500-nm homogeneous circles, respectively. The average travel distance for kidneys using heterogeneous, and 250-nm and 500-nm fixed-distance circles was 173 nm, 134 nm, and 269 nm, respectively. Heterogeneous circles reduce geographic disparity compared to homogeneous circles, while maintaining reasonable travel distances.

Balancing Efficiency and Fairness in Liver Transplant Access: Tradeoff Curves for the Assessment of Organ Distribution Policies

BACKGROUND

Current distribution policies have resulted in persistent geographic disparity in access to donated livers across the country for waitlisted candidates.

METHODS

Using mathematical optimization, and subsequently the Liver Simulation Allocation Model, the following organ distribution concepts were assessed: (1) current policy, (2) proposed alternative models, and (3) a novel continuous distribution model. A number of different scenarios for each policy distribution concept were generated and analyzed through efficiency-fairness tradeoff curves.

RESULTS

The continuous distribution concept allowed both for the greatest reduction in patient deaths and for the most equitable geographic distribution across comparable organ transportation burden. When applied with an Optimized Prediction of Mortality allocation scheme, continuous distribution allowed for a significant reduction in number of deaths-on the order of 500 lives saved annually (https://livervis.github.io/).

CONCLUSIONS

Tradeoff curves allow for a visualized understanding on the efficiency/fairness balance, and have demonstrated that liver candidates awaiting transplant would benefit from a model employing continuous distribution as this holds the greatest advantage for mortality reduction. Development and implementation of continuous distribution models for all solid organ transplants may allow for minimization of the geographic disparity in organ distribution, and allow for efficient and fair access to a limited national resource for all candidates.

Viability testing of discarded livers with normothermic machine perfusion: Alleviating the organ shortage outweighs the cost

BACKGROUND

Over 700 donor livers are discarded annually in the United States due to high risk of poor graft function. The objective of this study was to determine the impact of using normothermic machine perfusion to identify transplantable livers among those currently discarded.

STUDY DESIGN

A series of 21 discarded human livers underwent viability assessment during normothermic machine perfusion. Cross-sectional analysis of the Scientific Registry of Transplant Recipients database and cost analysis was performed to extrapolate the case series to national experience.

RESULTS

21 discarded human livers were included in the perfusion cohort. 11 of 20 (55%) eligible grafts met viability criteria for transplantation. Grafts in the perfusion cohort had a similar donor risk index compared with discarded grafts (n = 1402) outside of New England in 2017 and 2018 (median [IQR]: 2.0 [1.5, 2.4] vs. 2.0 [1.7, 2.3], P = .40). 705 (IQR 677-741) livers were discarded annually in the United States since 2005, translating to the potential for 398 additional transplants nationally. The median cost to identify a transplantable graft with machine perfusion was $28,099 USD.

CONCLUSIONS

Normothermic machine perfusion of discarded livers could identify a significant number of transplantable grafts, significantly improving access to liver transplantation.

Impact of Acuity Circles on Outcomes for Pediatric Liver Transplant Candidates

BACKGROUND

In December 2018, United Network for Organ Sharing approved an allocation scheme based on recipients' geographic distance from a deceased donor (acuity circles [ACs]). Previous analyses suggested that ACs would reduce waitlist mortality overall, but their impact on pediatric subgroups was not considered.

METHODS

We applied Scientific Registry of Transplant Recipients data from 2011 to 2016 toward the Liver Simulated Allocation Model to compare outcomes by age and illness severity for the United Network for Organ Sharing-approved AC and the existing donor service area-/region-based allocation schemes. Means from each allocation scheme were compared using matched-pairs t tests.

RESULTS

During a 3-year period, AC allocation is projected to decrease waitlist deaths in infants (39 versus 55; P < 0.001), children (32 versus 50; P < 0.001), and teenagers (15 versus 25; P < 0.001). AC allocation would increase the number of transplants in infants (707 versus 560; P < 0.001), children (677 versus 547; P < 0.001), and teenagers (404 versus 248; P < 0.001). AC allocation led to decreased median pediatric end-stage liver disease/model for end-stage liver disease at transplant for infants (29 versus 30; P = 0.01), children (26 versus 29; P < 0.001), and teenagers (26 versus 31; P < 0.001). Additionally, AC allocation would lead to fewer transplants in status 1B in children (97 versus 103; P = 0.006) but not infants or teenagers. With AC allocation, 77% of pediatric donor organs would be allocated to pediatric candidates, compared to only 46% in donor service area-/region-based allocation (P < 0.001).

CONCLUSIONS

AC allocation will likely address disparities for pediatric liver transplant candidates and recipients by increasing transplants and decreasing waitlist mortality. It is more consistent with federally mandated requirements for organ allocation.

Aggressive utilization of liver allografts: Improved outcomes over time

BACKGROUND

Aggressive acceptance of liver allografts has driven utilization of marginal allografts. Our aim was to assess the impact of the aggressive phenotype on transplant center outcomes over time.

METHODS

We used a cohort of 148 361 candidates from the Organ Procurement and Transplantation Network for liver transplantation between 2002 and 2016 in 134 centers. Using the Discard Risk Index, we designated high probability discard allografts by the top 10th percentile for likelihood of discard. Aggressive phenotype was defined by usage of high probability discard (HPD) allografts (top 10th percentile). Our analysis of survival on waitlist and graft survival after transplantation included a comprehensive list of center level covariates across three equal time periods (2002-2006, 2007-2011, and 2012-2016).

RESULTS

After adjusting for recipient and center-level factors, aggressive centers had improving graft survival over time. Aggressive vs non-aggressive centers: 2002-2006 HR 1.12 (1.05-1.19), 2007-2011 HR 1.13 (1.05-1.22), 2012-2016 HR 0.99 (0.89-1.10). Aggressive centers had improved waitlist survival compared with non-aggressive centers after adjusting for allograft disparity.

CONCLUSIONS

Aggressive phenotype had a positive impact on waitlist survival, and graft survival in aggressive centers have improved to benchmark levels over time. These findings serve as justification for aggressive utilization of allografts.

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.

Racial disparities in patient selection for liver transplantation: An ongoing challenge

Ample evidence suggests continued racial disparities once listed for liver transplantation, though few studies examine disparities in the selection process for listing. The objective of this study, via retrospective chart review, was to determine whether listing for liver transplantation was influenced by socioeconomic status and race/ethnicity. We identified 1968 patients with end-stage liver disease who underwent evaluation at a large, Midwestern center from January 1, 2004 through December 31, 2012 (72.9% white, 19.6% black, and 7.5% other). Over half (54.6%) of evaluated patients were listed; the three most common reasons for not listing were medical contraindications (11.9%), patient expired during evaluation (7.0%), and psychosocial contraindications (5.9%). In multivariable logistic regressions (listed vs not listed), across the three racial categories, the odds of being listed were lower for alcohol-induced hepatitis (±hepatitis C), unmarried, more than one insurance, inadequate insurance, and lower annual household income quartile. Similar factors predicted time to transplant listing, including being identified as black race. Black race, even when adjusting for the above mentioned medical and socioeconomic factors, was associated with 26% lower odds of being listed and a longer time to listing decision compared to all other patients.

Geographic Disparity in Deceased Donor Liver Transplant Rates Following Share 35

BACKGROUND

The Organ Procurement and Transplantation Network implemented Share 35 on June 18, 2013, to broaden deceased donor liver sharing within regional boundaries. We investigated whether increased sharing under Share 35 impacted geographic disparity in deceased donor liver transplantation (DDLT) across donation service areas (DSAs).

METHODS

Using Scientific Registry of Transplant Recipients June 2009 to June 2017, we identified 86 083 adult liver transplant candidates and retrospectively estimated Model for End-Stage Liver Disease (MELD)-adjusted DDLT rates using nested multilevel Poisson regression with random intercepts for DSA and transplant program. From the variance in DDLT rates across 49 DSAs and 102 programs, we derived the DSA-level median incidence rate ratio (MIRR) of DDLT rates. MIRR is a robust metric of heterogeneity across each hierarchical level; larger MIRR indicates greater disparity.

RESULTS

MIRR was 2.18 pre-Share 35 and 2.16 post-Share 35. Thus, 2 candidates with the same MELD in 2 different DSAs were expected to have a 2.2-fold difference in DDLT rate driven by geography alone. After accounting for program-level heterogeneity, MIRR was attenuated to 2.10 pre-Share 35 and 1.96 post-Share 35. For candidates with MELD 15-34, MIRR decreased from 2.51 pre- to 2.27 post-Share 35, and for candidates with MELD 35-40, MIRR increased from 1.46 pre- to 1.51 post-Share 35, independent of program-level heterogeneity in DDLT. DSA-level heterogeneity in DDLT rates was greater than program-level heterogeneity pre- and post-Share 35.

CONCLUSIONS

Geographic disparity substantially impacted DDLT rates before and after Share 35, independent of program-level heterogeneity and particularly for candidates with MELD 35-40. Despite broader sharing, geography remains a major determinant of access to DDLT.

Migration of Patients for Liver Transplantation and Waitlist Outcomes

BACKGROUND & AIMS

Patients in need of liver transplantation may travel to improve their chance of receiving an organ. We evaluated factors to determine which transplant candidates travel to other regions to increase their chances of receiving a liver and effects of travel on waitlist outcomes.

METHODS

We performed a retrospective cohort study of all adult patients registered for primary deceased donor liver transplantation in the United States from January 2004 to December 2016. Zip code data were used to calculate the travel distance from a patient's residence to centers at which they were on the waitlist or received a liver transplant. Distant listing and migration were defined as placement on a waitlist and receipt of liver transplantation, respectively, outside the home transplantation region and greater than 500 miles from the home zip code. We assessed the effect of distant listing on outcomes (death and liver transplantation) and predictors of distant listing or migration using multivariable analyses.

RESULTS

There were 104,914 waitlist registrations during the study period; of these, 2930 (2.8%) pursued listing at a distant center. Of waitlist registrants, 60,985 received liver transplants, of whom 1985 (3.3%) had migrated. In a multivariable competing risk analysis in which liver transplantation was considered as a competing event, distant listing was associated with a 22% reduction in the risk of death within 1 year (subhazard ratio, 0.78; 95% CI, 0.70-0.88). Distant listing and migration were associated with non-black race, non-Medicaid payer, residence in a higher income area, and education beyond high school.

CONCLUSIONS

Placement on a liver transplant waitlist outside the home transplantation region is associated with reduced waitlist mortality and an increased probability of receiving a liver transplant. Geographic disparities in access to liver transplantation have disproportionate effects on patients who are minorities, have lower levels of education, or have public insurance.

A Survey of Current Procurement Travel Practices, Accident Frequency, and Perceptions of Safety

Supplemental Digital Content is available in the text.

In 2018, 81% of the 36, 529 solid organs transplanted in the United States came from deceased donors. These organs were recovered through widespread use of aeromedical and emergency ground transportation systems. Urgently scheduled travel to remote hospitals at night and in varied weather conditions carries risk for the transplant professionals involved. A landmark survey conducted in 2007 demonstrated that 80% of respondents had experienced a “near-miss” event while on a procurement trip, and 15% had been involved in at least 1 accident. One decade later, we sought to revisit the issue of procurement related travel safety.

Influence of the procurement surgeon on transplanted abdominal organ outcomes: An SRTR analysis to evaluate regional organ procurement collaboration

Single-center studies have demonstrated regional organ procurement collaboration to reduce travel redundancy and improve procurement efficiency. We studied deceased donor kidney, liver, and pancreas transplants performed in the United States between 2002 and 2014 using the Scientific Registry of Transplant Recipients (SRTR). We compared graft failure (GF), death-censored graft failure (DCGF), and patient death (PD) between organs procured by surgeons from the recipient's center (transplant procurement team [TPT]) versus surgeons from a different center (NTPT). Primary nonfunction (PNF) was assessed for liver and kidney and delayed graft function (DGF) for kidney using mixed-effects logistic modeling. There were 64 906 liver (61.6% TPT), 118 152 kidney (26.1% TPT), 10 832 simultaneous pancreas kidney (SPK; 56.6% TPT), and 4378 solitary pancreas (SP; 34.0% TPT) transplants. When compared to NTPT, DCGF for organs procured by TPT was significantly less for liver (adjusted HR: 0.93; 95% CI: 0.88-0.98) and marginally significant for kidney (0.97; 0.93-1.00) and SPK (0.90; 0.82-1.00), and not significant for SP (0.98; 0.86 -1.11). DGF for TPT kidney was significantly lower (adjusted OR 0.91; 0.87-0.95). Albeit modest, our findings demonstrate a difference between locally procured organs and those procured by the implanting team. Elucidating the etiology of these differences will enhance regional organ procurement collaboration.

Geographic disparities in liver supply/demand ratio within fixed-distance and fixed-population circles

Recent OPTN proposals to address geographic disparity in liver allocation have involved circular boundaries: the policy selected 12/17 allocated to 150-mile circles in addition to DSAs/regions, and the policy selected 12/18 allocated to 150-mile circles eliminating DSA/region boundaries. However, methods to reduce geographic disparity remain controversial, within the OPTN and the transplant community. To inform ongoing discussions, we studied center-level supply/demand ratios using SRTR data (07/2013-06/2017) for 27 334 transplanted deceased donor livers and 44 652 incident waitlist candidates. Supply was the number of donors from an allocation unit (DSA or circle), allocated proportionally (by waitlist size) to the centers drawing on these donors. We measured geographic disparity as variance in log-transformed supply/demand ratio, comparing allocation based on DSAs, fixed-distance circles (150- or 400-mile radius), and fixed-population (12- or 50-million) circles. The recently proposed 150-mile radius circles (variance = 0.11, P = .9) or 12-million-population circles (variance = 0.08, P = .1) did not reduce the geographic disparity compared to DSA-based allocation (variance = 0.11). However, geographic disparity decreased substantially to 0.02 in both larger fixed-distance (400-mile, P < .001) and larger fixed-population (50-million, P < .001) circles (P = .9 comparing fixed distance and fixed population). For allocation circles to reduce geographic disparities, they must be larger than a 150-mile radius; additionally, fixed-population circles are not superior to fixed-distance circles.

Geographic inequity in transplant access

PURPOSE OF REVIEW

Scarcity is a defining feature of the modern transplant landscape, and in light of chronic shortages in donor organs, there is cause for concern about geographic inequities in patients' access to lifesaving resources. Recent policy changes designed to ameliorate unequal donor supply and demand have brought new interest to measuring and addressing disparities at all stages of transplant care. The purpose of this review is to describe an overview of recent literature on geographic inequities in transplant access, focusing on kidney, liver, and lung transplantation and the impact of policy changes on organ allocation.

RECENT FINDINGS

Despite a major change to the kidney allocation policy in 2014, geographic inequity in kidney transplant access remains. In liver transplantation, the debate has centered on the median acuity score at transplantation; however, a more thorough examination of disparities in access and survival has emerged.

SUMMARY

Geographic differences in access and quality of transplant care are undeniable, but existing disparity metrics reflect disparities only among candidates who are waitlisted. Future research should address major gaps in our understanding of geographic inequity in transplant access, including patients who may be transplant-eligible but experience a wide variety of barriers in accessing the transplant waiting list.

Geographic disparities in lung transplant rates

In November 2017, in response to a lawsuit from a New York City lung transplant candidate, an emergency change to the lung allocation policy eliminated the donation service area (DSA) as the first geographic tier of allocation. The lawsuit claimed that DSA borders are arbitrary and that allocation should be based on medical priority. We investigated whether deceased-donor lung transplant (LT) rates differed substantially between DSAs in the United States before the policy change. We estimated LT rates per active person-year using multilevel Poisson regression and empirical Bayes methods. We found that the median incidence rate ratio (MIRR) of transplant rates between DSAs was 2.05, meaning a candidate could be expected to double their LT rate by changing their DSA. This can be compared directly to a 1.54-fold increase in LT rate that we found associated with an increase in lung allocation score (LAS) category from 38-42 to 42-50. Changing a candidate's DSA would have had a greater impact on the candidate's LT rate than changing LAS categories from 38-42 to 42-50. In summary, we found that the DSA of listing was a major determinant of LT rate for candidates across the country before the emergency lung allocation change.

Disparities in the treatment of hepatocellular carcinoma based on geographical region are decreasing

BACKGROUND AND AIM

Geographic differences have existed in the management of hepatocellular carcinoma (HCC), and efforts to reduce regional disparities have been initiated. The aim of this study is to use the Nationwide Inpatient Sample to determine if regional disparities in the treatment of HCC continue to exist.

METHOD

A retrospective database analysis using the Nationwide Inpatient Sample was performed that included patients with a primary diagnosis of HCC. Logistic regression models were utilized to determine geographic disparities in liver decompensation, treatment, inpatient mortality, and metastatic disease.

RESULTS

This study's locational reach of 62 604 patients included 22 769 patients from the South (36%), 14 554 in the Northeast (23%), 14 041 in the West (22%), and 11 240 in the Midwest (18%). Patients who received treatment in the West were more likely to have inpatient mortality (OR 1.28, 95% CI 1.03, 1.53) than patients who received treatment in the Midwest. No significant differences were observed between rates of resection, ablation, and transarterial chemoembolization when comparing by region. Rates of liver transplantation were lower in the West compared with the Midwest (OR 0.51, 95% CI 0.29, 0.87). There was no significant difference between other regions.

CONCLUSION

Geographic disparities in the treatment of HCC are improving.

Proximity to transplant center and outcome among liver transplant patients

In the United States, distance from liver transplant center correlates with worsened outcomes; the effects of geography elsewhere are unassessed. We performed a national registry analysis of United Kingdom listings for liver transplantation (1995-2014) and assessed whether travel time to transplant center correlates with outcome. There were 11 188 listings assessed (8490 transplanted), with a median travel time to center of 60 minutes (range 36-86). Of the national population, 3.38 × 10⁷ (55.1%) reside ≥60 minutes from a center, and 7.65 × 10⁶ (12.5%) >119 minutes. After competing risk analysis, increasing travel time was associated with an increased risk of death after listing (subdistribution hazard ratios relative to <60 minutes of 1.33 for 60-119 and 1.27 for >119 minutes; P < 0.001) and reduced likelihood of transplantation or recovery (0.94 and 0.86; P < 0.001). Among those transplanted, travel time was not associated with retransplant-free survival (P = 0.532). We used our model to examine optimal placement of a new center and identify a single site with a total travel time reduction of ≈10%. Our findings of disparities in accessibility of liver transplantation showed worse outcomes following listing in those distant from their transplant center, and our description of a method to model a new center complement existing data and support similar analyses of other networks.

Directed solutions to address differences in access to liver transplantation

The United Network for Organ Sharing recently altered current liver allocation with the goal of decreasing Model for End-Stage Liver Disease (MELD) variance at transplant. Concerns over these and further planned revisions to policy include predicted decrease in total transplants, increased flying and logistical complexity, adverse impact on areas with poor quality health care, and minimal effect on high MELD donor service areas. To address these issues, we describe general approaches to equalize critical transplant metrics among regions and determine how they alter MELD variance at transplant and organ supply to underserved communities. We show an allocation system that increases minimum MELD for local allocation or preferentially directs organs into areas of need decreases MELD variance. Both models have minimal adverse effects on flying and total transplants, and do not disproportionately disadvantage already underserved communities. When combined together, these approaches decrease MELD variance by 28%, more than the recently adopted proposal. These models can be adapted for any measure of variance, can be combined with other proposals, and can be configured to automatically adjust to changes in disease incidence as is occurring with hepatitis C and nonalcoholic fatty liver disease.

Current opinions in organ allocation

Existing methods of academic publication provide limited opportunity to obtain stakeholder input on issues of broad interest. This article reports the results of an experiment to produce a collaborative, crowdsourced article examining a current controversial issue in transplant medicine (hereby referred to as the "C4 Article"). The editorial team as a whole selected the topic of organ allocation, then divided into six sections, each supported by an individual editorial team. Widely promoted by the American Journal of Transplantation, the C4 Article was open for public comment for 1 month. The nonblinded editorial teams reviewed the contributions daily and interacted with contributors in near-real time to clarify and expand on the content received. Draft summaries of each section were posted and subsequently revised as new contributions were received. One hundred ninety-four individuals viewed the manuscript, and 107 individuals contributed to the manuscript during the submission period. The article engaged the international transplant community in producing a contemporary delineation of issues of agreement and controversy related to organ allocation and identified opportunities for new policy development. This initial experience successfully demonstrated the potential of a crowdsourced academic manuscript to advance a broad-based understanding of a complex issue.

Organ distribution without geographic boundaries: A possible framework for organ allocation

The Final Rule mandates that organ allocation not be based on the transplant candidate's place of residence or listing, except as required by sound medical judgment and best use of donated organs, to avoid wasting organs and futile transplants, and to promote access and efficiency. Current Organ Procurement and Transplantation Network (OPTN) policies use donation service areas and OPTN regions to distribute and allocate organs for transplant. These policies have recently been called into question as not meeting the requirements of the Final Rule. Therefore, we propose using borderless allocation scores that combine medical priority scores with geographic feasibility scores. Medical priority scores are currently used in OPTN allocation policy, for example, the model for end-stage liver disease and the lung allocation score. Geographic feasibility scores can be developed to account for the effects of ischemia due to travel times, donor characteristics that modify the feasibility of traveling due to organ outcomes, and the costs of shipping organs over long distances. A borderless distribution and allocation system could address the goals of equity and utility, while fulfilling the mandates of the Final Rule and providing optimal use of a scare resource.

Patients From Appalachia Have Reduced Access to Liver Transplantation After Wait-Listing

BACKGROUND

The Appalachian region is medically underserved and characterized by high morbidity and mortality. We investigated disparities among patients listed for liver transplantation (LT) in wait-list outcomes, according to residence in the Appalachian region.

METHODS

Data on adult patients listed for LT were obtained from the United Network for Organ Sharing for July 2013 to December 2015. Wait-list outcomes were compared using cause-specific hazard models by region of residence (Appalachian vs non-Appalachian) among patients listed at centers serving Appalachia. Posttransplant patient and graft survival were also compared. The study included 1835 LT candidates from Appalachia and 5200 from non-Appalachian regions, of whom 1016 patients experienced wait-list mortality or were delisted; 3505 received liver transplants.

RESULTS

In multivariable analyses, patients from Appalachia were less likely to receive LT (hazard ratio [HR] = 0.86; 95% confidence interval [CI]: 0.79-0.93; P < .001), but Appalachian residence was not associated with wait-list mortality or delisting (HR = 1.03; 95% CI: 0.89-1.18; P = .696). Among liver transplant recipients, patient and graft survival did not differ by Appalachian versus non-Appalachian residence.

CONCLUSION

Appalachian residence was associated with lower access to transplantation after listing for LT. This geographic disparity should be addressed in the current debate over reforming donor liver allocation and patient priority for LT.

Geographic Variability in Liver Disease-Related Mortality Rates in the United States

PURPOSE

Liver disease is an important cause of morbidity and mortality in the United States. Geographic variations in the burden of chronic liver disease may have significant impact on public health policies but have not been explored at the national level. The objective of this study is to examine interstate variability in liver disease mortality in the United States.

METHODS

We compared liver disease mortality from the 2010 National Vital Statistics Report on a state level. States in each quartile of liver disease mortality were compared with regard to viral hepatitis death rates, alcohol consumption, obesity, ethnic and racial composition, and household income. Race, ethnicity, and median household income data were derived from the 2010 US Census. Alcohol consumption and obesity data were obtained from the 2010 Behavioral Risk Factor Surveillance System Survey.

RESULTS AND CONCLUSION

We found significant interstate variability in liver disease mortality, ranging from 6.4 to 17.0 per 100,000. The South and the West carry some of the highest rates of liver disease mortality. In addition to viral hepatitis death rates, there is a strong correlation between higher percentage of Hispanic population and a state's liver disease mortality rate (r = 0.538, P < .001). Lower household income (r = 0.405, P = .003) was also associated with the higher liver disease mortality. While there was a trend between higher obesity rates and higher liver disease mortality, the correlation was not strong and there was no clear association between alcohol consumption and liver disease mortality rates.

Adding to the mounting evidence for geographic inequity in liver transplantation: Hospital length of stay

BACKGROUND

Severe geographic inequities in liver transplantation have persisted for years. Previous investigators have demonstrated 90-day transplant rates varying from 14% to 82% and death rates varying from 18% to 86%. The aim of this analysis was to utilize a robust multivariate analysis to investigate whether geographic inequities affected the length of stay after liver transplantation.

METHODS

We conducted a unique Kaplan-Meier analysis with the event being discharge from the hospital and length of stay as the time to the event, using a cohort of 66 674 recipients listed in the UNOS database from 2002 to 2016. Multivariate Cox regression using 43 covariates was used for time-to-event analysis.

RESULTS

Region 9 (0.82; CI 0.79-0.85), Region 2 (0.85; CI 0.83-0.88), and Region 10 (0.96; CI 0.93-0.99) were statistically significant factors for prolonged hospital stay. The following covariates were the most significant factors for prolonged hospital stay: serum sodium >150 mEq/L (0.70; CI 0.62-0.78), ICU admission (0.77; CI 0.74-0.80), hospital admission (0.81; 0.79-0.83), region 9 (0.82; CI 0.79-0.85), and ventilator dependence (0.82; CI 0.76-0.88).

CONCLUSION

In this analysis, we demonstrate regional disparities in hospital length of stay that are significant in robust multivariable Cox regression analysis. We hope the transplant community will take immediate measures to correct geographic inequities.