The benefit of sharing
Authors: Julie K. Heimbach
Journal: Hepatology (2017)

Potential conflict of interest: Nothing to report. See Article On Page 273 Liver transplantation remains the only effective therapy for patients suffering from the complications of end‐stage liver disease. While transplantation can achieve excellent results, it is not available to all patients determined to be suitable candidates for transplantation due to the critical shortage of available donor liver allografts. The intent of the Model for End‐Stage Liver Disease (MELD) score, adopted in the United States in 2002, was to reduce mortality by more accurately prioritizing candidates according to disease severity.1 Patients with fulminant hepatic failure have long been recognized as being the most urgent as they have an anticipated survival of less than 7 days; thus, they were granted the highest priority under the MELD allocation system. After adoption of the MELD system, it was observed that time to transplant and wait‐list outcomes differed around the country and that these differences were getting worse not better. Sharing for status 1 candidates for the Organ Procurement and Transplantation Network region, which was adopted in 2010, instead of by the donor‐service area followed by the region had the intended effect of reducing mortality for status 1 candidates and was relatively uncontroversial.2 Subsequent efforts by the transplant community to reduce differences in access to liver transplantation based on geography have been ongoing. A proposal to share for all liver transplant candidates within a region was considered, but due to significant concern about the magnitude of such a change as well as other objections, it was ultimately not adopted. Instead, a system of regional sharing for candidates with a MELD of 35 who were noted to have a similar urgency for transplantation to status 1 and higher, "Share 35," was approved and began in June 2013.3 In the current issue of Hepatology, Dr. Kwong and colleagues4 explore the impact of this policy revision by comparing outcomes for all adult, deceased, donor liver transplant recipients who underwent liver transplantation from January 2010 through March 2016. In this cohort, 47% of the candidates received a liver transplant after Share 35. Importantly, 1‐year patient and graft survival improved following the policy change to 90.6% and 88.7%, respectively, compared to 89.9% and 87.7% before the implementation of Share 35 (P < 0.04 for both comparisons). As would be anticipated, the improvement in outcome was concentrated in the patients with MELD ≥35, where an improvement of patient survival from 83.9% to 88.4% (P < 0.01) was noted, while patients with a MELD <35 experienced similar outcomes before and after Share 35. Other key findings included the observation that patients with MELD ≥35 received organs with a slightly lower donor risk index than prior to the policy change, suggesting that surgeons preferentially selected organs of higher quality for candidates with MELD ≥35. It is important to note that being a "regionally shared" organ was a negative marker of organ quality prior to the institution of Share 35 as it indicated an organ that was declined by the local candidates. Because this variable was no longer relevant after the mandatory regional allocation of organs under Share 35, it was removed from the donor risk index calculation for the current analysis. Contrary to a prior analysis, no region experienced higher mortality after Share 35, although trends toward worse outcomes were seen in regions 6 and 10, while the regions identified in the prior analysis to be experiencing worse outcomes post‐Share 35 were 4 and 10.5 Patients with hepatitis C virus experienced improved outcomes regardless of MELD stratum in the post‐Share 35 era, while other recipient diagnoses and donor variables demonstrated no difference. Travel times were not reported in the current analysis, but the impact on cold ischemia time was mixed, showing an increase from 6.6 to 6.7 hours (P < 0.01) for the MELD ≥35 group but a decrease from 6.5 to 6.2 hours (P < 0.01) for the MELD <35 group. The adoption of Share 35 has not been without controversy, and the authors detail some of the concerns. A lack of survival benefit was noted in the initial report by Massie et al.,3 although this may have been simply insufficient length of follow‐up. In some cases, the exact same data, such as the selection of better quality organs for sicker patients, have been presented by different authors as either a positive or a negative consequence of broader sharing.4 Other controversies not discussed in the current analysis include a significant concern over logistics, particularly as it related to the percentage of organs flown, as well as concerns about cost.7 It has been reported in both large database analyses as well as a single center analysis that overall costs decrease due to reduced time and readmission prior to liver transplantation.8 However, the cost savings generated by a more timely transplantation for the sickest patients may not be shared by the transplant centers and organ procurement organizations who may bear the cost of increased transportation and other logistical issues.7 The current manuscript is timely and of importance because it demonstrates that Share 35 accomplished the intended goals of the policy, which were to reduce mortality while prioritizing livers to the most urgent candidates. The process of policy development for Share 35 was arduous and relied on extensive statistical modeling produced by the Scientific Registry of Transplant Recipients. The predictions made by the models on the impact of Share 35 have been validated by outcomes presented in the current analysis. The observation that the policy did what it was intended and what the models predicted is of critical importance as the current Organ Procurement and Transplantation Network Liver Committee strives to develop further policy changes to reduce geographic disparity in accordance with the final rule.11 Over the past 5 years, proposals developed that would share organs more broadly so that the most ill patients may be able to undergo transplantation have been met with considerable skepticism and concern from the community. Similar to what has been observed on the national political scene, there has been little consensus reached thus far. However, by working together, the liver transplant community has previously solved significant challenges, most importantly being able to perfect a highly complex procedure such that excellent long‐term survival for patients undergoing liver transplantation is now the rule rather than the exception. Hopefully, with perseverance and collaboration, revisions to the current system of liver distribution can be adopted that will improve both outcomes and equity in access to transplantation.