Addressing geographic disparities in liver transplantation through redistricting

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.

Geographic disparity in kidney transplantation under KAS

The Kidney Allocation System fundamentally altered kidney allocation, causing a substantial increase in regional and national sharing that we hypothesized might impact geographic disparities. We measured geographic disparity in deceased donor kidney transplant (DDKT) rate under KAS (6/1/2015-12/1/2016), and compared that with pre-KAS (6/1/2013-12/3/2014). We modeled DSA-level DDKT rates with multilevel Poisson regression, adjusting for allocation factors under KAS. Using the model we calculated a novel, improved metric of geographic disparity: the median incidence rate ratio (MIRR) of transplant rate, a measure of DSA-level variation that accounts for patient casemix and is robust to outlier values. Under KAS, MIRR was _1.75 1.81_1.86 for adults, meaning that similar candidates across different DSAs have a median 1.81-fold difference in DDKT rate. The impact of geography was greater than the impact of factors emphasized by KAS: having an EPTS score ≤20% was associated with a 1.40-fold increase (IRR = _1.35 1.40_1.45 , P < .01) and a three-year dialysis vintage was associated with a 1.57-fold increase (IRR = _1.56 1.57_1.59 , P < .001) in transplant rate. For pediatric candidates, MIRR was even more pronounced, at _1.66 1.92_2.27 . There was no change in geographic disparities with KAS (P = .3). Despite extensive changes to kidney allocation under KAS, geography remains a primary determinant of access to DDKT.

New paradigms for organ allocation and distribution in liver transplantation

PURPOSE OF REVIEW

The 'Final Rule,' issued by the Health Resources and Service Administration in 2000, mandated that liver allocation policy should be based on disease severity and probability of death, and - among other factors - should be independent of a candidate's residence or listing. As a result, the Organ Procurement Transplantation Network/United Network for Organ Sharing (UNOS) has explored policy changes addressing geographic disparities without compromising outcomes.

RECENT FINDINGS

Major paradigm shifts are underway in U.S. liver allocation policy. New hepatocellular carcinoma exception policy incorporates tumor characteristics associated with posttransplantation outcomes, whereas a National Liver Review Board will promote a standardized process for awarding exception points. Meanwhile, following extensive debate, new allocation policy aims to reduce geographic disparity by broadening sharing to the UNOS region and 150-mile circle around the donor hospital for liver transplant candidates with a calculated model for end-stage liver disease score at least 32. Unnecessary organ travel will be reduced by granting 3 'proximity points' to candidates within the same donation service area (DSA) as a liver donor or within 150 nautical miles of the donor hospital, regardless of DSA or UNOS region.

SUMMARY

This review provides an evaluation of major policy changes in liver allocation from 2016 to 2018.

Intraregional model for end-stage liver disease score variation in liver transplantation: Disparity in our own backyard

Variation in average Model for End-Stage Liver Disease (MELD) score at liver transplantation (LT) by United Network for Organ Sharing (UNOS) regions is well documented. The present study aimed to investigate MELD variation at the interregional, intraregional, and intra-donation service area (DSA) levels. Patients undergoing LT between 2015 and 2016 were obtained from the UNOS standard analysis and research file. The distribution of allocation MELD score including median, skew, and kurtosis was examined for all transplant programs. Intraregional median allocation MELD varied significantly within all 11 UNOS regions. The largest variation between programs was seen in region 5 (MELD 24.0 versus 38.5) and region 3 (MELD 20.5 versus 32.0). Regions 1, 5, and 9 had the largest proportion of programs with a highly negative skewed MELD score (50%, 57%, and 57%, respectively), whereas regions 3, 6, 10, and 11 did not have any programs with a highly negative skew. MELD score distribution was also examined in programs located in the same DSA, where no barriers exist and theoretically no significant difference in allocation should be observed. The largest DSA variation in median allocation MELD score was seen in NYRT-OP1 LiveOnNY (MELD score variation 11), AZOB-OP1 Donor Network of Arizona (MELD score variation 11), MAOB-OP1 New England Organ Bank (MELD score variation 9), and TXGC-OP1 LifeGift Organ Donation Ctr (MELD score variation 9). In conclusion, the present study demonstrates that this MELD disparity is not only present at the interregional level but can be seen within regions and even within DSAs between programs located as close as several city blocks away. Although organ availability likely accounts for a component of this disparity, the present study suggests that transplant center behavior may also play a significant role. Liver Transplantation 24 488-496 2018 AASLD.

Between-center disparities in access to heart transplantation in France: contribution of candidate and center factors - A comprehensive cohort study

Transplantation represents the last option for patients with advanced heart failure. We assessed between-center disparities in access to heart transplantation in France 1 year after registration and evaluated the contribution of factors to these disparities. Adults (n = 2347) registered on the French national waiting list between January 1, 2010, and December 31, 2014, in the 23 transplant centers were included. Associations between candidate and transplant center characteristics and access to transplantation were assessed by proportional hazards frailty models. Candidate blood groups O and A, sensitization, and body mass index ≥30 kg/m² were independently associated with lower access to transplantation, while female gender, severity of heart failure, and high serum bilirubin levels were independently associated with greater access to transplantation. Center factors significantly associated with access to transplantation were heart donation rate in the donation service area, proportion of high-urgency candidates among listed patients, and donor heart offer decline rate. Between-center variability in access to transplantation increased by 5% after adjustment for candidate factors and decreased by 57% after adjustment for center factors. After adjustment for candidate and center factors, five centers were still outside of normal variability. These findings will be taken into account in the future French heart allocation system.

Liver transplantation for chronic hepatitis C virus infection in the United States 2002-2014: An analysis of the UNOS/OPTN registry

Chronic hepatitis C virus (HCV) infection is a leading cause for orthotopic liver transplantation (OLT) in the U.S. We investigated characteristics of HCV-infected patients registered for OLT, and explored factors associated with mortality. Data were obtained from the United Network for Organ Sharing and Organ Procurement and Transplantation network (UNOS/OPTN) registry. Analyses included 41,157 HCV-mono-infected patients ≥18 years of age listed for cadaveric OLT between February 2002 and June 2014. Characteristics associated with pre- and post-transplant survival and time trends over the study period were determined by logistic and Cox proportional hazard regression analyses and Poisson regressions. Most patients were white (69.1%) and male (70.8%). At waitlist registration, mean age was 54.6 years and mean MELD was 16. HCC was recorded in 26.9% of the records. A total of 51.2% of the patients received an OLT, 21.0% died or were too sick; 15.6% were delisted and 10.4% were still waiting. Factors associated with increased waitlist mortality were older age, female gender, blood type 0, diabetes, no HCC and transplant region (p<0.001). OLT recipient characteristics associated with increased risk for post OLT mortality were female gender, age, diabetes, race (p<0,0001), and allocation MELD (p = 0.005). Donor characteristics associated with waitlist mortality included age, ethnicity (p<0.0001) and diabetes (p<0.03). Waitlist registrations and OLTs for HCC significantly increased from 14.4% to 37.3% and 27.8% to 38.5%, respectively (p<0.0001). Pre- and post-transplant survival depended on a variety of patient-, donor-, and allocation- characteristics of which most remain relevant in the DAA-era. Still, intensified HCV screening strategies and timely and effective treatment of HCV are highly relevant to reduce the burden of HCV-related OLTs in the U.S.

Long Cold Ischemia Times in Same Hospital Deceased Donor Transplants

BACKGROUND

Recent changes in deceased donor organ allocation for livers (Share-35) and kidneys (kidney allocation system) have resulted in broader sharing of organs and increased cold ischemia time (CIT). Broader organ sharing however is not the only cause of increased CIT.

METHODS

This was a retrospective registry study of CIT in same-hospital liver transplants (SHLT, n = 4347) and same-hospital kidney transplants (SHKT, n = 9707) between 2004 and 2014.

RESULTS

In SHLT, median (interquartile range) CIT was 5.0 (3.5-6.5) hours versus 6.6 (5.1-8.4) hours in other-hospital LT. donation after circulatory death donors, donor biopsy, male recipient, recipient obesity, and previous transplant were associated with increased CIT. Model for End-Stage Liver Disease at transplant of 29+ or status 1a was associated with decreased CIT. SHLT CIT varied by Organ Procurement Organization and transplant-center (P < 0.01), with center median CIT ranging from 2.0 to 7.8 hours across 118 centers. In SHKT, CIT was 13.0 (8.5-19.0) hours versus 16.5 (11.3-22.6) hours in other-hospital KT. Overweight donors, donation after cardiac death donors, right-kidney, donor biopsy, recipient obesity, use of mechanical perfusion, additional KT procedures on the same day, and transplant center annual volume were associated with increased CIT. Older donor age, extended criteria donors, and underweight recipients were associated with decreased CIT. SHKT CIT varied by Organ Procurement Organization and transplant-center (P < 0.001), with center median CIT ranging from 3.3 to 29 hours across 206 centers. Transplant centers with longer SHKT also had longer SHLT (P = 0.01).

CONCLUSIONS

Same-hospital transplants already have a significant amount of CIT, even without transporting the organ to another hospital.

A Concentric Neighborhood Solution to Disparity in Liver Access That Contains Current UNOS Districts

BACKGROUND

Policymakers are deliberating reforms to reduce geographic disparity in liver allocation. Public comments and the United Network for Organ Sharing Liver and Intestinal Committee have expressed interest in refining the neighborhoods approach. Share 35 and Share 15 policies affect geographic disparity.

METHODS

We construct concentric neighborhoods superimposing the current 11 regions. Using concepts from concentric circles, we construct neighborhoods for each donor service area (DSA) that consider all DSAs within 400, 500, or 600 miles as neighbors. We consider limiting each neighborhood to 10 DSAs and use no metrics for liver supplies and demands. We change Model for End-Stage Liver Disease (MELD) thresholds for the Share 15 policy to 18 or 20 and apply 3- and 5-point MELD proximity boosts to enhance local priority, control travel distances, and reduce disparity. We conduct simulations comparing current allocation with the neighborhoods and sharing policies.

RESULTS

Concentric neighborhoods structures provide an array of solutions where simulation results indicate that they reduce geographic disparity, annual mortalities, and the airplane travel distances by varying degrees. Tuning of the parameters and policy combinations can lead to beneficial improvements with acceptable transplant volume loss and reductions in geographic disparity and travel distance. Particularly, the 10-DSA, 500-mile neighborhood solution with Share 35, Share 15, and 0-point MELD boost achieves such while limiting transplant volume losses to below 10%.

CONCLUSIONS

The current 11 districts can be adapted systematically by adding neighboring DSAs to improve geographic disparity, mortality, and airplane travel distance. Modifications to Share 35 and Share 15 policies result in further improvements. The solutions may be refined further for implementation.

The donor risk index: A decade of experience

In 2006, derivation of the donor risk index (DRI) highlighted the importance of donor factors for successful liver transplantation. Over the last decade, the DRI has served as a useful metric of donor quality and has enhanced our understanding of donor factors and their impact upon recipients with hepatitis C virus, those with low Model for End-Stage Liver Disease (MELD) score, and individuals undergoing retransplantation. DRI has provided the transplant community with a common language for describing donor organ characteristics and has served as the foundation for several tools for organ risk assessment. It is a useful tool in assessing the interactions of donor factors with recipient factors and their impact on posttransplant outcomes. However, limitations of statistical modeling, choice of donor factors, exclusion of unaccounted donor and geographic factors, and the changing face of the liver transplant recipient have tempered its widespread use. In addition, the DRI was derived from data before the MELD era but is currently being applied to expand the donor pool while concurrently meeting the demands of a dynamic allocation system. A decade after its introduction, DRI remains relevant but may benefit from being updated to provide guidance in the use of extended criteria donors by accounting for the impact of geography and unmeasured donor characteristics. DRI could be better adapted for recipients with nonalcoholic fatty liver disease by examining and including recipient factors unique to this population. Liver Transplantation 23 1216-1225 2017 AASLD.

Mortality Risk Factors Among Patients With Cirrhosis and a Low Model for End-Stage Liver Disease Sodium Score (≤15): An Analysis of Liver Transplant Allocation Policy Using Aggregated Electronic Health Record Data

Although the Model for End-Stage Liver Disease sodium (MELD Na) score is now used for liver transplant allocation in the United States, mortality prediction may be underestimated by the score. Using aggregated electronic health record data from 7834 adult patients with cirrhosis, we determined whether the cause of cirrhosis or cirrhosis complications was associated with an increased risk of death among patients with a MELD Na score ≤15 and whether patients with the greatest risk of death could benefit from liver transplantation (LT). Over median follow-up of 2.3 years, 3715 patients had a maximum MELD Na score ≤15. Overall, 3.4% were waitlisted for LT. Severe hypoalbuminemia, hepatorenal syndrome, and hepatic hydrothorax conferred the greatest risk of death independent of MELD Na score with 1-year predicted mortality >14%. Approximately 10% possessed these risk factors. Of these high-risk patients, only 4% were waitlisted for LT, despite no difference in nonliver comorbidities between waitlisted patients and those not listed. In addition, risk factors for death among waitlisted patients were the same as those for patients not waitlisted, although the effect of malnutrition was significantly greater for waitlisted patients (hazard ratio 8.65 [95% CI 2.57-29.11] vs. 1.47 [95% CI 1.08-1.98]). Using the MELD Na score for allocation may continue to limit access to LT.

Contemporary Issues in Lung Transplant Allocation Practices

PURPOSE OF REVIEW

To discuss the current state of donor lung allocation in the United States, and future opportunities to increase the efficiency of donor lung allocation.

RECENT FINDINGS

The current donor lung allocation system prioritizes clinical acuity by use of the Lung Allocation Score (LAS) which has reduced waitlist mortality since its implementation in 2005. Access to donor lungs can be further improved through policy changes using broader geographic sharing, and developing new technology such as ex vivo lung perfusion to recover marginal donor lungs.

SUMMARY

The number of lung transplants in the U.S. continues to increase annually. However, the demand for donor lungs continues to be outpaced by an ever growing waitlist. Efficient allocation can be achieved through improved allocation policies and new technology.

Avoiding Futility in Simultaneous Liver-kidney Transplantation: Analysis of 331 Consecutive Patients Listed for Dual Organ Replacement

OBJECTIVE

We sought to evaluate outcomes and predictors of renal allograft futility (RAF-patient death or need for renal replacement therapy at 3 months) after simultaneous liver-kidney transplantation (SLKT).

BACKGROUND

Model for End-Stage Liver Disease (MELD) prioritization of liver recipients with renal dysfunction has significantly increased utilization of SLKT. Data on renal outcomes after SLKT in the highest MELD recipients are scarce, as are accurate predictors of recovery of native kidney function. Without well-established listing guidelines, SLKT potentially wastes renal allografts in both high-acuity liver recipients at risk for early mortality and recipients who may regain native kidney function.

METHODS

A retrospective single-center multivariate regression analysis was performed for adult patients undergoing SLKT (January 2004 to August 2014) to identify predictors of RAF.

RESULTS

Of 331 patients dual-listed for SLKT, 171 (52%) expired awaiting transplant, 145 (44%) underwent SLKT, and 15 (5%) underwent liver transplantation alone. After SLKT, 39% experienced delayed graft function and 20.7% had RAF. Compared with patients without RAF, RAF recipients had greater MELD scores, length of hospitalization, intraoperative base deficit, incidence of female donors, kidney and liver donor risk indices, kidney cold ischemia, and inferior overall survival. Multivariate predictors of RAF included pretransplant dialysis duration, kidney cold ischemia, kidney donor risk index, and recipient hyperlipidemia.

CONCLUSIONS

With 20% short-term loss of transplanted kidneys after SLKT, our data strongly suggest that renal transplantation should be deferred in liver recipients at high risk for RAF. Consideration for a kidney allocation variance to allow for delayed renal transplantation after liver transplantation may prevent loss of scarce renal allografts.

Regional Differences in Communication Process and Outcomes of Requests for Solid Organ Donation

Although federal mandate prohibits the allocation of solid organs for transplantation based on "accidents of geography," geographic variation of transplantable organs is well documented. This study explores regional differences in communication in requests for organ donation. Administrative data from nine partnering organ procurement organizations and interview data from 1339 family decision makers (FDMs) were compared across eight geographically distinct US donor service areas (DSAs). Authorization for organ donation ranged from 60.4% to 98.1% across DSAs. FDMs from the three regions with the lowest authorization rates reported the lowest levels of satisfaction with the time spent discussing donation and with the request process, discussion of the least donation-related topics, the highest levels of pressure to donate, and the least comfort with the donation decision. Organ procurement organization region predicted authorization (odds ratios ranged from 8.14 to 0.24), as did time spent discussing donation (OR = 2.11), the number of donation-related topics discussed (OR = 1.14), and requesters' communication skill (OR = 1.14). Standardized training for organ donation request staff is needed to ensure the highest quality communication during requests, optimize rates of family authorization to donation in all regions, and increase the supply of organs available for transplantation.

Noneligible Donors as a Strategy to Decrease the Organ Shortage

Organ procurement organization (OPO) performance is generally evaluated by the number of organ procurement procedures divided by the number of eligible deaths (donation after brain death [DBD] donors aged <70 years), whereas the number of noneligible deaths (including donation after cardiac death donors and DBD donors aged >70 years) is not tracked. The present study aimed to investigate the variability in the proportion of noneligible liver donors by the 58 donor service areas (DSAs). Patients undergoing liver transplant (LT) between 2011 and 2015 were obtained from the United Network for Organ Sharing Standard Transplant Analysis and Research file. LTs from noneligible and eligible donors were compared. The proportion of noneligible liver donors by DSA varied significantly, ranging from 0% to 19.6% of total liver grafts used. In transplant programs, the proportion of noneligible liver donors used ranged from 0% to 35.3%. On linear regression there was no correlation between match Model for End-Stage Liver Disease score for programs in a given DSA and proportion of noneligible donors used from the corresponding DSA (p = 0.14). Noneligible donors remain an underutilized resource in many OPOs. Policy changes to begin tracking noneligible donors and learning from OPOs that have high noneligible donor usage are potential strategies to increase awareness and pursuit of these organs.

Same policy, different impact: Center-level effects of share 35 liver allocation

Early studies of national data suggest that the Share 35 allocation policy increased liver transplants without compromising posttransplant outcomes. Changes in center-specific volumes and practice patterns in response to the national policy change are not well characterized. Understanding center-level responses to Share 35 is crucial for optimizing the policy and constructing effective future policy revisions. Data from the United Network for Organ Sharing were analyzed to compare center-level volumes of allocation-Model for End-Stage Liver Disease (aMELD) ≥ 35 transplants before and after policy implementation. There was significant center-level variation in the number and proportion of aMELD ≥ 35 transplants performed from the pre- to post-Share 35 period; 8 centers accounted for 33.7% of the total national increase in aMELD ≥ 35 transplants performed in the 2.5-year post-Share 35 period, whereas 25 centers accounted for 65.0% of the national increase. This trend correlated with increased listing at these centers of patients with Model for End-Stage Liver Disease (MELD) ≥ 35 at the time of initial listing. These centers did not overrepresent the total national volume of liver transplants. Comparison of post-Share 35 aMELD to calculated time-of-transplant (TOT) laboratory MELD scores showed that only 69.6% of patients transplanted with aMELD ≥ 35 maintained a calculated laboratory MELD ≥ 35 at the TOT. In conclusion, Share 35 increased transplantation of aMELD ≥ 35 recipients on a national level, but the policy asymmetrically impacted practice patterns and volumes of a subset of centers. Longer-term data are necessary to assess outcomes at centers with markedly increased volumes of high-MELD transplants after Share 35. Liver Transplantation 23 741-750 2017 AASLD.

Increased Risk of Death for Patients on the Waitlist for Liver Transplant Residing at Greater Distance From Specialized Liver Transplant Centers in the United States

BACKGROUND

We have previously shown that patients listed for orthotopic liver transplantation (OLT) in United Network for Organ Sharing Region 4 (Texas and Oklahoma) have higher waitlist mortality rates when residing more than 30 miles from specialized liver transplant centers (LTC). Considering that findings might only be exclusive for this region with its peculiarities in terms of having the highest land surface extensions, lowest population densities, and largest rural populations. We investigated the entire OLT patient population in the United States to assess if our previous regional findings are nationally validated and if a rural, micropolitan, or metropolitan residence location affects outcome of waitlisted OLT patients in the nation.

METHODS

Patients waiting for OLT in the United States from 2002 to 2012 were stratified by distance from the patients' residence to LTC and by Rural Urban Commuting Area (RUCA) codes classification. Statistical analyses were performed to evaluate risk of mortality on the waitlist and the likelihood to receive an OLT using a Cox proportional hazards model and a generalized additive model with a logistic link.

RESULTS

Survival time and probability of death while on the waitlist for OLT using distance to LTC showed significant increased risk with the distance (P = 0.001 and P < 0.0001, respectively). At the same time, using RUCA classification as the variable did not show significance (P = 0.14 and P = 0.73, respectively).

CONCLUSIONS

Distance from an LTC is a risk factor of mortality on the waitlist for OLT, whereas RUCA classification is not a significant factor.

From Data to Improved Decisions: Operations Research in Healthcare Delivery

BACKGROUND

The Operations Research Interest Group (ORIG) within the Society of Medical Decision Making (SMDM) is a multidisciplinary interest group of professionals that specializes in taking an analytical approach to medical decision making and healthcare delivery. ORIG is interested in leveraging mathematical methods associated with the field of Operations Research (OR) to obtain data-driven solutions to complex healthcare problems and encourage collaborations across disciplines. This paper introduces OR for the non-expert and draws attention to opportunities where OR can be utilized to facilitate solutions to healthcare problems.

METHODS

Decision making is the process of choosing between possible solutions to a problem with respect to certain metrics. OR concepts can help systematically improve decision making through efficient modeling techniques while accounting for relevant constraints. Depending on the problem, methods that are part of OR (e.g., linear programming, Markov Decision Processes) or methods that are derived from related fields (e.g., regression from statistics) can be incorporated into the solution approach. This paper highlights the characteristics of different OR methods that have been applied to healthcare decision making and provides examples of emerging research opportunities.

EXAMPLES

We illustrate OR applications in healthcare using previous studies, including diagnosis and treatment of diseases, organ transplants, and patient flow decisions. Further, we provide a selection of emerging areas for utilizing OR.

CONCLUSIONS

There is a timely need to inform practitioners and policy makers of the benefits of using OR techniques in solving healthcare problems. OR methods can support the development of sustainable long-term solutions across disease management, service delivery, and health policies by optimizing the performance of system elements and analyzing their interaction while considering relevant constraints.

The Impact of the Share 35 Policy on Racial and Ethnic Disparities in Access to Liver Transplantation for Patients with End Stage Liver Disease in the United States: An Analysis from UNOS Database

BACKGROUND

The Share 35 policy was instituted in June 2013 by the United Network for Organ Sharing (UNOS) in order to reduce death on liver transplant waiting list. The effect of this policy on racial and ethnic disparities in access to liver transplantation has not been examined.

METHODS

A total of 14,585 adult patients registered for liver transplantation between 2012 and 2015 were identified from UNOS database. Logistic and proportional hazards models were used to model the effects of race and ethnicity on access to liver transplantation. Stratification on pre- and post-Share 35 periods was performed to compare the first 18 months of Share 35 policy to an equivalent time period before.

RESULTS

Comparison of the pre- and post-Share 35 periods showed significantly decreased time on waiting list and increased numbers of minorities having access to liver transplantation. Hispanic recipients still experienced significantly longer waiting time (HR: 0.69, 95% CI: 0.53-0.88) before they received liver transplantation after Share 35 policy took effect.

CONCLUSION

The Share 35 policy did not lead to improved access to liver transplantation among minorities but eliminated the previously observed racial and ethnic disparities in transplant rates as well as shortened the waiting time.

Distance is associated with mortality on the waitlist in pediatric liver transplantation

The distance to liver transplant centers affects outcomes in adult liver transplantation. Because pediatric patients are particularly vulnerable, we hypothesized that distance adversely affects the time to transplantation and waitlist mortality. The SRTR was queried for isolated pediatric liver transplant registrants (under age 18) with valid ZIP code information from 2003 to 2012. Distance was measured from home ZIP code to listing transplant center. Competing events analysis, adjusted for demographic factors, indication, and PELD, was undertaken for transplantation and death while on the waitlist. The median distance to listing transplant center for 6924 children was 65 (IQR 17.5-189) miles. Median distance traveled increased by listing volume (73.9 vs 33.8 miles, highest vs lowest volume quartile, P<.001 for trend) and varied across the country. Longer distance was not associated with time to transplantation (HR 0.99, longest vs shortest distance quartile, P=.80), but was associated with increased mortality (HR 1.75, P<.001). Larger centers attract patients from a distance, while smaller centers serve local populations. Increasing distance is associated with a higher risk of waitlist death, which may reflect decreased access to specialist and tertiary care associated with a transplant center.

Choice of Allograft in Patients Requiring Intestinal Transplantation: A Critical Review

Intestinal transplantation (ITx) is indicated in patients with irreversible intestinal failure (IF) and life-threatening complications related to total parenteral nutrition (TPN). ITx can be classified into three main types. Isolated intestinal transplantation (IITx), that is, transplantation of the jejunoileum, is indicated in patients with preserved liver function. Combined liver-intestine transplantation (L-ITx), that is, transplantation of the liver and the jejunoileum, is indicated in patients with liver failure related to TPN. Thus, patients with cirrhosis or advanced fibrosis should receive a combined allograft, while patients with lower grades of liver fibrosis can usually safely undergo ITx. Reflecting their degree of sickness, the waitlist mortality rate and the early posttransplant outcomes of patients receiving L-ITx are worse than IITx. However, L-ITx is associated with better long-term graft and patient survival. Multivisceral transplantation (MVTx), that is, transplantation of the organs dependent on the celiac axis and superior mesenteric artery, can be classified into full MVTx if it includes the liver and modified MVTx if it does not. The most common indications for MVTx are extensive portomesenteric thrombosis and diffuse gastrointestinal pathology such as motility disorders and polyposis syndrome. Every patient with IF should undergo a multidisciplinary evaluation by an experienced ITx team.

Global lessons in graft type and pediatric liver allocation: A path toward improving outcomes and eliminating wait-list mortality

Current literature and policy in pediatric liver allocation and organ procurement are reviewed here in narrative fashion, highlighting historical context, ethical framework, technical/procurement considerations, and support for a logical way forward to an equitable pediatric liver allocation system that will improve pediatric wait-list and posttransplant outcomes without adversely affecting adults. Where available, varying examples of successful international pediatric liver allocation and split-liver policy will be compared to current US policy to highlight potential strategies that can be considered globally. Liver Transplantation 23:86-95 2017 AASLD.

The Current State of Liver Transplantation in the United States: Perspective From American Society of Transplant Surgeons (ASTS) Scientific Studies Committee and Endorsed by ASTS Council

This article is a review of the salient points and a future prospective based on the 2014 Organ Procurement and Transplantation Network (OPTN)/Scientific Registry of Transplant Recipients (SRTR) liver donation and transplantation data report recently published by the American Journal of Transplantation. Emphasis of our commentary and interpretation is placed on data relating to waitlist dynamics, organ utilization rates, the impact of recent advances in the treatment of hepatitis C, and the increases in end-stage renal disease among liver transplant candidates. Finally, we share our vision on potential areas of innovation that are likely to significantly improve the field of liver transplantation in the near future.

Patients With Hepatocellular Carcinoma Have Highest Rates of Wait-listing for Liver Transplantation Among Patients With End-Stage Liver Disease

BACKGROUND & AIMS

Despite recent attention to differences in access to livers for transplantation, research has focused on patients already on the wait list. We analyzed data from a large administrative database that represents the entire US population, and state Medicaid data, to identify factors associated with differences in access to wait lists for liver transplantation.

METHODS

We performed a retrospective cohort study of transplant-eligible patients with end-stage liver disease using the HealthCore Integrated Research Database (2006-2014; n = 16,824) and Medicaid data from 5 states (2002-2009; California, Florida, New York, Ohio, and Pennsylvania; n = 67,706). Transplant-eligible patients had decompensated cirrhosis, hepatocellular carcinoma (HCC), and/or liver synthetic dysfunction, based on validated International Classification of Diseases, Ninth Revision-based algorithms and data from laboratory studies. Placement on the wait list was determined through linkage with the Organ Procurement and Transplantation Network database.

RESULTS

In an unadjusted analysis of the HealthCore database, we found that 29% of patients with HCC were placed on the 2-year wait list (95% confidence interval [CI], 25.4%-33.0%) compared with 11.9% of patients with stage 4 cirrhosis (ascites) (95% CI, 11.0%-12.9%) and 12.6% of patients with stage 5 cirrhosis (ascites and variceal bleeding) (95% CI, 9.4%-15.2%). Among patients with each stage of cirrhosis, those with HCC were significantly more likely to be placed on the wait list; adjusted subhazard ratios ranged from 1.7 (for patients with stage 5 cirrhosis and HCC vs those without HCC) to 5.8 (for patients with stage 1 cirrhosis with HCC vs those without HCC). Medicaid beneficiaries with HCC were also more likely to be placed on the transplant wait list, compared with patients with decompensated cirrhosis, with a subhazard ratio of 2.34 (95% CI, 2.20-2.49). Local organ supply and wait list level demand were not associated with placement on the wait list.

CONCLUSIONS

In an analysis of US healthcare databases, we found patients with HCC to be more likely to be placed on liver transplant wait lists than patients with decompensated cirrhosis. Previously reported reductions in access to transplant care for wait-listed patients with decompensated cirrhosis underestimate the magnitude of this difference.

Impact of Liver Graft Transport on Postoperative Results and Short-Term Liver Survival

BACKGROUND

The Andalusian community has a specific management model of liver transplantation with a common waiting list, forcing transportation of 45% of hepatic grafts. These trips within the community have been made exclusively via expressway since 2012, sometimes surpassing 400 km in distance. The objective of this study was to analyze the effect of graft transportation on our community regarding postoperative results, primary dysfunction, and short-term graft survival.

METHODS

This was a retrospective observational cohort study that included 110 patients recipients of liver transplants from 2009 to 2012. Group A (n = 53) were patients transplanted with grafts removed in Malaga, and group B (n = 57) were patients with transported grafts.

RESULTS

In group B, significant increments in total and cold ischemia time (TIT and CIT) were found. We found a significant higher increase, mostly in 2012, in TIT and CIT in the greater transportation distance subgroup (>150 km). In postoperative variables analysis, differences were found in the bilirubin levels the 1st postoperative day, alkaline phosphatase levels the 1st and 3rd days, and factor V in the 1st day in favor of the nontransported grafts. In the multivariable analysis transport and distance travelled in km presented a relationship with the 1st day bilirubin levels and the primary dysfunction of the graft.

CONCLUSIONS

Our results point to graft transportation having an influence on primary dysfunction and graft survival. This relationship can be multifaceted and influenced by currently unknown factors. This is a factor to consider regarding liver transplant management strategy decisions.

Use of Population-based Data to Demonstrate How Waitlist-based Metrics Overestimate Geographic Disparities in Access to Liver Transplant Care

Liver allocation policies are evaluated by how they impact waitlisted patients, without considering broader outcomes for all patients with end-stage liver disease (ESLD) not on the waitlist. We conducted a retrospective cohort study using two nationally representative databases: HealthCore (2006-2014) and five-state Medicaid (California, Florida, New York, Ohio and Pennsylvania; 2002-2009). United Network for Organ Sharing (UNOS) linkages enabled ascertainment of waitlist- and transplant-related outcomes. We included patients aged 18-75 with ESLD (decompensated cirrhosis or hepatocellular carcinoma) using validated International Classification of Diseases, Ninth Revision (ICD-9)-based algorithms. Among 16 824 ESLD HealthCore patients, 3-year incidences of waitlisting and transplantation were 15.8% (95% confidence interval [CI] : 15.0-16.6%) and 8.1% (7.5-8.8%), respectively. Among 67 706 ESLD Medicaid patients, 3-year incidences of waitlisting and transplantation were 10.0% (9.7-10.4%) and 6.7% (6.5-7.0%), respectively. In HealthCore, the absolute ranges in states' waitlist mortality and transplant rates were larger than corresponding ranges among all ESLD patients (waitlist mortality: 13.6-38.5%, ESLD 3-year mortality: 48.9-62.0%; waitlist transplant rates: 36.3-72.7%, ESLD transplant rates: 4.8-13.4%). States' waitlist mortality and ESLD population mortality were not positively correlated: ρ = -0.06, p-value = 0.83 (HealthCore); ρ = -0.87, p-value = 0.05 (Medicaid). Waitlist and ESLD transplant rates were weakly positively correlated in Medicaid (ρ = 0.36, p-value = 0.55) but were positively correlated in HealthCore (ρ = 0.73, p-value = 0.001). Compared to population-based metrics, waitlist-based metrics overestimate geographic disparities in access to liver transplantation.

From Child-Pugh to Model for End-Stage Liver Disease: Deciding Who Needs a Liver Transplant

This article reviews the historical evolution of the liver transplant organ allocation policy and the indications/contraindications for liver transplant, and provides an overview of the liver transplant evaluation process. The article is intended to help internists determine whether and when referral to a liver transplant center is indicated, and to help internists to counsel patients whose initial evaluation at a transplant center is pending.

Liver transplant center variability in accepting organ offers and its impact on patient survival

BACKGROUND & AIMS

Despite an allocation system designed to give deceased-donor livers to the sickest patients, many transplantable livers are declined by U.S. transplant centers. It is unknown whether centers vary in their propensities to decline organs for the highest priority patients, and how these decisions directly impact patient outcomes.

METHODS

We analyzed Organ Procurement and Transplantation Network (OPTN) data from 5/1/07-6/17/13, and included all adult liver-alone waitlist candidates offered an organ that was ultimately transplanted. We evaluated acceptance rates of liver offers for the highest ranked patients and their subsequent waitlist mortality.

RESULTS

Of the 23,740 unique organ offers, 8882 (37.4%) were accepted for the first-ranked patient. Despite adjusting for organ quality and recipient severity of illness, transplant centers within and across geographic regions varied strikingly (p<0.001) in the percentage of organ offers they accepted for the highest priority patients. Among all patients ranked first on waitlists, the adjusted center-specific organ acceptance rates ranged from 15.7% to 58.1%. In multivariable models, there was a 27% increased odds of waitlist mortality for every 5% absolute decrease in a center's adjusted organ offer acceptance rate (adjusted OR: 1.27, 95% CI: 1.20-1.32). However, the absolute difference in median 5-year adjusted graft survival was 4% between livers accepted for the first-ranked patient, compared to those declined and transplanted at a lower position.

CONCLUSION

There is marked variability in center practices regarding accepting livers allocated to the highest priority patients. Center-level decisions to decline organs substantially increased patients' odds of dying on the waitlist without a transplant.

Determinants of outcome among patients with acute liver failure listed for liver transplantation in the United States

Analyses of outcomes after acute liver failure (ALF) have typically included all ALF patients regardless of whether they were listed for liver transplantation (LT). We hypothesized that limiting analysis to listed patients might provide novel insights into factors associated with outcome, focusing attention on disease evolution after listing. Listed adult ALF patients enrolled in the US Acute Liver Failure Study Group registry between 2000 and 2013 were analyzed to determine baseline factors associated with 21-day outcomes after listing. We classified 617 patients (36% of overall ALF group) by 3-week outcome after study admission: 117 were spontaneous survivors (SSs; survival without LT), 108 died without LT, and 392 underwent LT. Only 22% of N-acetyl-p-aminophenol (APAP) ALF patients were listed; however, this group of 173 patients demonstrated greater illness severity: higher coma grades and more patients requiring ventilator, vasopressor, or renal replacement therapy support. Only 62/173 (36%) of APAP patients received a graft versus 66% for drug-induced liver injury patients, 86% for autoimmune-related ALF, and 71% for hepatitis B-related ALF. APAP patients were more likely to die than non-APAP patients (24% versus 17%), and the median time to death was sooner (2 versus 4.5 days). Despite greater severity of illness, the listed APAP group still had a SS rate of 40% versus 11% for non-APAP causes (P < 0.001). APAP outcomes evolve rapidly, mainly to SS or death. Patients with APAP ALF listed for LT had the highest death rate of any etiology, whereas more slowly evolving etiologies yielded higher LT rates and, consequently, fewer deaths. Decisions to list and transplant must be made early in all ALF patients, particularly in those with APAP ALF.

Current Issues in Liver Transplantation

The state of liver transplantation continues to evolve. This article focuses on 3 separate yet important issues within this field. First, there is a proposal to change the allocation of donor livers in the United States. The fundamental premise of this proposal is to equalize access to donor livers across the country. To accomplish this goal, the proposal is to increase the geographic area of liver allocation. As might be expected, there is a great deal of controversy surrounding the possibility of a major change in liver allocation and distribution. A second area of interest, and perhaps the most important therapeutic breakthrough in the field of hepatology, is the introduction of direct-acting antiviral agents against hepatitis C virus (HCV) infection. With cure rates up to 100%, an increasing proportion of liver transplant candidates and recipients are being cured of HCV infection with therapies that have minimal side effects. Consequently, the impact of HCV infection on patient and graft survival will likely improve substantially over the next few years. Finally, this article reviews the role of donor-specific antibodies (DSAs) in antibody-mediated rejection. Long recognized as an important factor in graft survival in renal transplantation, DSAs have recently been shown to be a strong predictor of graft and patient survival in liver transplantation. However, the importance of DSAs in liver transplantation is uncertain, in large part due to the absence of proven therapies.

Current Status of Liver Allocation in the United States

The liver transplant allocation system is currently based upon the Model for End-Stage Liver Disease (MELD) score and allocates organs preferentially to patients with the highest scores (ie, the sickest patients) within a defined geographic unit. In addition, certain patient populations, such as patients with hepatocellular carcinoma and portopulmonary hypertension, receive MELD exception points to account for their increased waitlist mortality, which is not reflected by their MELD score. Significant geographic variation in the access to liver transplantation exists throughout the United States. Both the Organ Procurement and Transplant Network Board of Directors and the Health Resources and Services Administration have determined these geographic disparities to be unacceptable. The liver transplant community has worked to develop methods to reduce these geographic disparities and to reexamine how MELD exception points are granted to certain patient populations. As a result, numerous policy changes have been adopted throughout the years that have broadened the sharing of organs through wider geographic sharing. Despite all of these changes, variation in access to liver transplantation continues to exist, and, thus, the liver transplant community continues to examine new ways to address geographic disparities. This paper reviews several of the key changes to the liver allocation system that have occurred since the implementation of MELD allocation in 2002 and provides an overview of potential changes to the system.

Changes in liver acceptance patterns after implementation of Share 35

The Share 35 policy was implemented June 2013. We sought to evaluate liver offer acceptance patterns of centers under this policy. We compared three 1-year eras (1, 2, and 3) before and 1 era (4) after the implementation date of the Share 35 policy (June 18, 2013). We evaluated all offers for liver-only recipients including only those offers for livers that were ultimately transplanted. Logistic regression was used to develop a liver acceptance model. In era 3, there were 4809 offers for Model for End-Stage Liver Disease (MELD) score ≥ 35 patients with 1071 acceptances (22.3%) and 10,141 offers and 1652 acceptances (16.3%) in era 4 (P < 0.001). In era 3, there were 42,954 offers for MELD score < 35 patients with 4181 acceptances (9.7%) and 44,137 offers and 3882 acceptances (8.8%) in era 4 (P < 0.001). The lower acceptance rate persisted across all United Network for Organ Sharing regions and was significantly less in regions 2, 3, 4, 5, and 7. Mean donor risk index was the same (1.3) for all eras for MELD scores ≥ 35 acceptances and the same (1.4) for MELD score < 35 acceptances. Refusal reasons did not vary throughout the eras. The adjusted odds ratio of accepting a liver for a MELD score of 35 + compared to a MELD score < 35 patient was 1.289 before the policy and 0.960 after policy implementation. In conclusion, the Share 35 policy has resulted in more offers to patients with MELD scores ≥ 35. Overall acceptance rates were significantly less compared to the same patient group before the policy implementation. Centers are less likely to accept a liver for a patient with a MELD score of 35 + after the policy change. Decreased donor acceptance rates could reflect more programmatic selectivity and ongoing donor and recipient matching.

The Impact of Redistricting Proposals on Health Care Expenditures for Liver Transplant Candidates and Recipients

Redistricting, which means sharing organs in novel districts developed through mathematical optimization, has been proposed to reduce pervasive geographic disparities in access to liver transplantation. The economic impact of redistricting was evaluated with two distinct data sources, Medicare claims and the University HealthSystem Consortium (UHC). We estimated total Medicare payments under (i) the current allocation system (Share 35), (ii) full regional sharing, (iii) an eight-district plan, and (iv) a four-district plan for a simulated population of patients listed for liver transplant over 5 years, using the liver simulated allocation model. The model predicted 5-year transplant volumes (Share 35, 29,267; regional sharing, 29,005; eight districts, 29,034; four districts, 28,265) and a reduction in overall mortality, including listed and posttransplant patients, of up to 676 lives. Compared with current allocation, the eight-district plan was estimated to reduce payments for pretransplant care ($1638 million to $1506 million, p < 0.001), transplant episode ($5607 million to $5569 million, p < 0.03) and posttransplant care ($479 million to $488 million, p < 0.001). The eight-district plan was estimated to increase per-patient transportation costs for organs ($8988 to $11,874 per patient, p < 0.001) and UHC estimated hospital costs ($4699 per case). In summary, redistricting appears to be potentially cost saving for the health care system but will increase the cost of performing liver transplants for some transplant centers.

Treatment strategies for chronic hepatitis C prior to and following liver transplantation

Hepatitis C virus (HCV)-related liver disease is the leading indication for liver transplantation (LT) worldwide. However, HCV is an independent predictor of lower survival following LT, and recurrence of HCV post-LT is virtually universal. The historic standard of care during the interferon era of HCV therapy was expectant management-initiation of antiviral therapy in the setting of documented disease progression following LT. With the advent of new direct acting antiviral (DAA) therapies for HCV, the paradigm of expectant treatment for recurrent HCV infection post-LT is shifting. The safety, tolerability, and efficacy of DAAs, even among the sickest patients with advanced liver disease, enables treatment of HCV in the pre-transplant setting among LT waitlist registrants. Finally, emerging data are supportive of preemptive therapy with DAAs in liver transplant recipients as the preferred approach. Expectant management of HCV following LT can rarely be justified in the modern era of HCV therapy.