Since 2002, the Model for End-Stage Liver Disease (MELD) score has been used to prioritize patients listed for liver transplantation in the United States. In the first 2 years of MELD-based allocation, 24% of transplant recipients had a laboratory MELD score less than 15 at the time of transplantation, and there were geographic differences in the distribution of such patients.1, 2 This was a concern because patients with MELD scores less than 15 also had a greater risk of dying 1 year after transplantation in comparison with remaining on the wait list.1 In response, the Organ Procurement and Transplantation Network/United Network for Organ Sharing (UNOS) in 2005 adopted the Share 15 policy with the goal of improving regional organ allocation. This policy states that organs must be offered first to local patients with MELD scores of 15 or greater and then to regional patients with MELD scores of 15 or greater before they are made available to local patients with MELD scores less than 15.3
Although organ allocation is primarily driven by the MELD score, transplant centers may apply for exception points from their regional review boards (RRBs) for patients whose MELD scores underestimate their true risk of waitlist mortality. Even though the MELD Exception Study Group has published evidence-based consensus recommendations regarding the granting of exception points,4 regional variations in the application of such points still exist.2
Since the implementation of the Share 15 policy, there has been no focused evaluation of exception point applications in response to this policy. We hypothesized that the inconsistency in the utilization of exception points and the lack of standardization in their allocation could be mitigating the potential benefits of a regional sharing policy. The goals of this study were to provide a greater understanding of exception point applications since the adoption of the Share 15 policy and to highlight their effects on the current organ allocation system by (1) determining whether there have been changes in the applications for 15 MELD exception points since the initiation of the Share 15 policy, (2) describing the patterns of applications for 15 MELD exception points and the acceptance of these exception point applications, and (3) determining the impact of applications for 15 MELD exception points on the utilization of organs by patients with low MELD scores.
PATIENTS AND METHODS
All analyses were based on Organ Procurement and Transplantation Network data from January 1, 2005 to March 14, 2011. The start date of January 1, 2005 was chosen because it was the initiation date of the current regional Share 15 policy. Before this date, there were only 5 applications for 15 MELD exception points between February 27, 2002 and December 31, 2004. We included all waitlisted candidates who were adults (≥18 years old) at the time of listing and applied to an RRB for 15 exception points. We included only initial transplant candidates and excluded patients listed for retransplantation because (1) the MELD score has been validated only for predicting the waitlist mortality of patients listed for initial transplantation5 and (2) using a MELD score less than 15 as an indicator of higher posttransplant mortality puts the focus on patients listed for initial transplantation.1 We identified exception point applicants by analyzing UNOS Standard Transplant Analysis and Research files, which included the requested exception score, the reason for the exception point application (based on 11 possible codes), the entire narrative submitted by the transplant center, and the result of the application. We included only candidates who had at least 1 exception point application for 15 points (the UNOS variable request score was equal to 15).
Each narrative was reviewed in detail (T.B.), and a random sample (10%) received a second review (D.G.). According to the individual narrative, each application was assigned to 1 of 14 categories (see Table 1). When a narrative requested exception points for more than 1 condition, the application was categorized according to the predominant clinical condition described in the narrative.
Table 1. Reasons for Exception Point Applications
|Recurrent bacterial cholangitis|
|Recurrent variceal bleeding (esophageal and/or gastric)|
|Other liver tumors*|
|Spontaneous bacterial peritonitis|
|Refractory hepatic hydrothorax|
|Portal vein or superior mesenteric vein thrombosis|
|Other gastrointestinal bleeding not due to varices|
|Portopulmonary hypertension or hepatopulmonary syndrome|
|Symptomatic polycystic liver disease|
During the review of the narratives, it was noted that a number of applications specifically requested exception points to achieve MELD scores high enough for a patient to receive an organ. These were categorized as follows: (1) requesting points to make a patient eligible or considered for a transplant, (2) requesting points to gain access to organs or to keep organs local, (3) requesting points to gain access to regional organs, and (4) requesting points to gain access to extended criteria organs [ie, organs with a high donor risk index (DRI)]. Each of these requests was made to allow the candidate to be assigned the 15 points needed to receive a local or regional organ under the Share 15 policy without the organ first having to be offered to a regional candidate with a MELD score less than 15. Thus, they were aggregated into the following category: asking for points to allow a patient to receive an organ under the Share 15 policy.
The primary outcome was the result of the application for exception points. The application had 5 potential outcomes based on the decision by the RRB: approved, denied, withdrawn, indeterminate, or not approved in 21 days. We categorized the results of applications as approved or denied (which included all other possible outcomes). In evaluating the outcomes of transplantation, we counted only recipients of deceased donor organs to account for organs that were allocated according to match MELD scores.
Wilcoxon rank-sum and Kruskall-Wallis tests were used for continuous variables, and chi-square tests were used for categorical variables because of the nonnormal distribution of the data. We compared application acceptance rates for (1) different UNOS regions and (2) different reasons for exception point applications. In assessing regional variations, we excluded region 9 because it was the only region with a single list, and the implications of the Share 15 policy and the need to apply for exception points to keep organs local did not apply.
We sought to determine whether there were differences in waitlist outcomes based on the acceptance or denial of an exception application. Because candidates may have applied for an exception more than 1 time with different results each time, the patients were categorized as follows: (1) all applications accepted, (2) all applications denied, or (3) at least 1 application accepted and at least 1 application denied.
Waitlisted candidates may have sought additional exception points after they applied for 15 points, or they may have had progressive liver disease with a laboratory MELD score rising higher than 15. To estimate the proportion of patients subsequently undergoing transplantation with a MELD score greater than 15, we dichotomized transplant recipients by their match MELD score at transplantation: >15 or ≤15. We calculated the DRI for transplant recipients with the formula established by Feng et al.6
We measured socioeconomic factors with residential zip code–level poverty, which is a measure used in previous transplantation literature.7 Using zip code data provided by UNOS, we measured neighborhood poverty by estimating the proportion of individuals residing below the federal poverty level within the area of a 5-digit zip code (an American FactFinder search was performed on July 5, 2012).8 We compared socioeconomic data for applicants for 15 MELD exception points to those for the entire waitlist pool during the study period.
All calculations were made with Stata version 12 (StataCorp, College Station, TX). This study received an exempt review from the institutional review board of the University of Pennsylvania.
Four hundred fifty-two applications for 15 exception points for 301 patients were submitted between January 1, 2005 and March 14, 2011; the mean number of applications per patient was 1.5 ± 1.2. Table 2 provides an overview of the patient demographics. In comparison with the general pool of waitlisted candidates, candidates applying for 15 exception points were less likely to be male (57.5% versus 64.6%, P = 0.01) and were more likely to be white (82.1% versus 73.7%, P < 0.001). The primary diagnoses of applicants for 15 MELD exception points also varied significantly from those of the overall pool; this was most notable for hepatitis C (20.6% versus 37.0%, P < 0.001), cholestatic liver disease (19.6% versus 7.8%, P < 0.001), alcoholic liver disease (8.3% versus 16.1%, P = 0.004), and polycystic liver disease (6.6% versus 0.4%, P < 0.001). During the study time period, there was a gradual increase in the numbers of applicants and applications per year (Table 3). As for socioeconomic factors, in comparison with the general pool of waitlisted candidates, a significantly greater proportion of applicants for 15 MELD exception points lived in neighborhoods in which less than 10% of the population lived below the federal poverty level. On the other hand, a significantly lower proportion lived in neighborhoods in which more than 20% lived above the poverty level (Supporting Table 1).
Table 2. Demographic Data for All Adults With at Least 1 Exception Application for 15 Points (n = 301)
|Age (years)*||54 (45-60)|
|Male sex [n (%)]||173 (57.5)|
|Race/ethnicity [n (%)]|| |
| White||247 (82.1)|
| Black||30 (10.0)|
| Hispanic||18 (6.0)|
| Asian||6 (2.0)|
|Primary diagnosis [n (%)]|| |
| Hepatitis C||62 (20.6)|
| Cholestatic||59 (19.6)|
| Nonalcoholic steatohepatitis/cryptogenic||45 (15.0)|
| Hepatocellular carcinoma||38 (12.6)|
| Alcoholic liver disease||25 (8.3)|
| Polycystic liver||20 (6.6)|
| Autoimmune liver disease||8 (2.7)|
| Hepatitis B||3 (1.0)|
| Other||41 (13.6)|
Table 3. Numbers of Applicants and Applications Per Year
|2005||35 (11.6)||36 (8.0)|
|2006||46 (15.3)||60 (13.3)|
|2007||40 (13.3)||61 (13.5)|
|2008||53 (17.6)||72 (15.9)|
|2009||69 (22.9)||114 (25.2)|
|2010||54 (17.9)||97 (21.5)|
|2011||4 (1.3)||12 (2.7)|
Reasons for Exception Point Applications
The primary reasons for exception point applications and the outcomes are detailed in Table 4. Four of the 14 reasons accounted for more than half of all applications: encephalopathy (15.9%), hepatocellular carcinoma (15.5%), refractory ascites (11.1%), and recurrent cholangitis (9.5%). There were no statistically significant differences in the application approval rates for each category (P = 0.61) or in the percentages of applicants undergoing transplantation (P = 0.11).
Table 4. Reasons for Exception Point Applications
|Encephalopathy||72 (15.9)||58 (80.6)||29 (40.3)||43 (14.3)||26 (60.5)|
|Hepatocellular carcinoma||70 (15.5)||56 (80.0)||19 (27.1)||63 (20.9)||52 (82.5)|
|Refractory ascites||50 (11.1)||37 (74.0)||19 (38.0)||39 (13.0)||21 (53.9)|
|Recurrent cholangitis||43 (9.5)||34 (79.1)||8 (18.6)||25 (8.3)||16 (64.0)|
|Pruritus||36 (8.0)||30 (83.3)||18 (50.0)||16 (5.3)||8 (50.0)|
|Symptomatic polycystic liver disease||35 (7.7)||32 (91.4)||1 (2.9)||19 (6.3)||14 (73.7)|
|Other liver tumors||26 (5.8)||23 (88.5)||10 (38.5)||21 (7.0)||12 (57.1)|
|Other reasons||29 (6.4)||21 (72.4)||11 (37.9)||17 (5.7)||13 (76.5)|
|Refractory hydrothorax||21 (4.6)||18 (85.7)||7 (33.3)||12 (4.0)||7 (58.3)|
|Recurrent variceal bleeding||23 (5.1)||17 (73.9)||6 (26.1)||17 (5.6)||12 (70.6)|
|Other gastrointestinal bleeding not due to varices||22 (4.9)||19 (86.4)||3 (13.6)||13 (4.3)||7 (53.8)|
|Portal vein or superior mesenteric vein thrombosis||15 (3.3)||11 (73.3)||7 (46.7)||8 (2.7)||3 (37.5)|
|Spontaneous bacterial peritonitis||6 (1.3)||6 (100.0)||1 (16.7)||5 (1.7)||3 (60.0)|
|Portopulmonary hypertension or hepatopulmonary syndrome||4 (0.9)||4 (100.0)||1 (25.0)||3 (1.0)||3 (100.0)|
The median laboratory MELD score of the entire cohort at the time of applying for exception points was 11 [interquartile range (IQR) = 9-14]. According to Kim et al.'s formula,9 the calculated Model for End-Stage Liver Disease sodium (MELD-Na) score for the entire cohort was 13 (IQR = 10-17). For the group of patients with ascites or hydrothorax, the median laboratory MELD score was 11 (IQR = 10-13), whereas the median MELD-Na score was 16 (IQR = 12-18).
One hundred forty-eight of the 452 applications (31.0%) specifically requested exception points so that a patient could receive an organ under the Share 15 policy (see the Patients and Methods section). There was variability across regions in the use of this specific language in the narratives. For example, 59 of 196 narratives from region 3 (30.1%) made specific mention of applying for exception points to receive an organ under the Share 15 policy, whereas only 13 of 130 from region 10 (10.0%) did (P < 0.001 for region 3 versus region 10).
Regional Variations in Exception Point Applications
There were significant regional differences in the numbers of applicants and applications (except for region 9, as noted in the Patients and Methods section; Table 5). Two hundred eight applicants (69.1%) were from regions 3 and 10, whereas 6 applicants (2.0%) were from regions 1 and 5. According to Organ Procurement and Transplantation Network/UNOS data (March 14, 2011), when region 9 was excluded (see the Patients and Methods section), 17.7% of all waitlisted candidates were from regions 3 and 10, whereas 33.3% were from regions 1 and 5. There was no correlation between the proportion of patients listed with an initial laboratory MELD score less than 15 and the proportion of applications for 15 MELD exception points in a region. In fact, region 3 had the lowest proportion of candidates with an initial listing laboratory MELD score less than 15, whereas region 10 had the fourth highest (data not shown). The overall approval rate was 81.0%; again, there were significant regional differences. In regions with more than 10 applications, the approval rate ranged from less than 70% (regions 7 and 10) to more than 90% (region 3).
Table 5. Regional Differences in Applications for 15 Exception Points
|2||46 (10.2)||31 (10.3)||41 (89.1)|
|3||196 (43.4)||103 (34.2)||182 (92.9)|
|5||10 (2.2)||6 (2.0)||7 (70.0)|
|6||2 (0.4)||2 (0.7)||2 (100.0)|
|7||26 (5.8)||20 (6.6)||16 (61.5)|
|8||7 (1.5)||6 (2.0)||2 (28.6)|
|10||130 (28.8)||105 (34.9)||87 (66.9)|
|11||35 (7.7)||28 (9.3)||29 (82.9)|
Data on the listing organ procurement organization (OPO) and the donor service area (DSA) were available for 292 of the 301 waitlisted candidates applying for 15 exception points (97%). One hundred forty-nine of the 292 patients with available data (51.0%) were listed in a noncompetitive DSA (a single-center DSA), whereas 143 (49.0%) were listed in a competitive DSA (a multicenter DSA). Fifty-two of the 143 patients (36.4%) were listed in a competitive DSA with 2 centers, 33 (23.1%) were listed in a competitive DSA with 3 centers, 20 (14.0%) were listed in a competitive DSA with 4 centers, and 38 (26.6%) were listed in a competitive DSA with at least 5 centers.
Outcomes of Exception Point Applicants
Two hundred twenty-three of the 301 applicants (74.1%) had all applications accepted, whereas 63 (20.9%) had all applications denied (Table 6). Overall, 197 applicants (65.4%) received a transplant, and 192 of these patients (97.5%) received a deceased donor organ. Of the 187 organs with available data, one hundred thirty-nine organs (74.3%) were locally shared, whereas 31 (16.6%) were regionally shared, and 17 (9.1%) were nationally shared.
Table 6. Outcomes of Applications for 15 Exception Points
|All applications approved||223 (74.1)||158 (72.1)||11 (9-14)||15 (15-16)||19 (8.5)||318 (126-1309)|
|Applications both accepted and rejected||15 (5.0)||5 (33.3)||10 (8-11)||15 (15-15)||2 (13.3)||386 (243-529)|
|All applications rejected||63 (20.9)||34 (54.0)||12 (11-14)||15 (12-18)||9 (14.3)||889 (404-1544)|
The median DRI was 1.56 (IQR = 1.16-1.86) for all candidates submitting exception point applications. When the median DRI was analyzed by region, it was higher for exception point applicants in regions 2, 3, 6, and 10 in comparison with all initial transplant recipients. However, these differences did not reach statistical significance in region 3 (P = 0.05) or region 10 (P = 0.09), and only 6 exception point applicants underwent transplantation in regions 2 and 6, so statistical testing was limited.
During the study period, similar proportions and numbers of patients underwent transplantation each year with a laboratory MELD score less than 15 at the time of transplantation (29.0%-34%, P = 0.94 for 2005-2011). On the regional level, the number of transplant recipients over time with laboratory MELD scores less than 15 was unchanged except for an increased proportion in region 8 and a decreased proportion in region 10. After the exclusion of all transplant recipients who ever received any number of exception points, there was a significantly lower proportion of patients undergoing transplantation each year with a laboratory MELD score less than 15 (from 16.2% in 2005 to 7.6% in 2010, P < 0.001 for 2005-2011).
Of 223 applications with all of their applications approved, 158 (72.1%) underwent transplantation. In contrast, of 63 applicants with all of there applications denied, 34 (54.0%) were transplanted, while among the 15 applicants with applications approved and denied 5 (33.3%) were transplanted (P = 0.001 for a comparison of the 3 groups). The risk of waitlist removal for death or clinical deterioration did not differ between patients with all applications approved and patients with all applications denied [8.5% (19/223) versus 14.3% (9/63), P = 0.36]. The median laboratory and match MELD scores at transplantation were similar for those with all applications approved and those with all applications denied.
The proportions of all applicants undergoing transplantation were similar across the UNOS regions (data not shown). All 4 regions in which at least 15 of these exception point applicants underwent transplantation (regions 2, 3, 10, and 11) had a median match MELD score of 15 at transplantation. One hundred ninety-seven applicants received a deceased donor organ; 70.1% of these patients (138/197) had a match MELD score of 15 or less, and 80.2% (158/197) had a laboratory MELD score less than 15 at the time of transplantation.
The outcomes of exception point applications in competitive DSAs versus noncompetitive DSAs were similar (P = 0.53). There were 149 applicants in noncompetitive DSAs: 71.8% had all their applications accepted, 23.5% had all their applications denied, and 4.7% had at least 1 application accepted and at least 1 application denied. In competitive DSAs, these numbers were 76.2%, 18.2%, and 5.6%, respectively. The rates of transplantation were not significantly different for waitlisted candidates in competitive and noncompetitive DSAs. One hundred two applicants (68.5%) from noncompetitive DSAs ultimately underwent transplantation, whereas 93 applicants (65.0%) in competitive DSAs did (P = 0.54).
This is the first study to demonstrate several important consequences of the Share 15 policy. Since January 1, 2005, there have been more than 450 applications for 15 MELD exception points; this phenomenon essentially did not exist before the implementation of the Share 15 policy. These applications were disproportionately concentrated in 2 regions (3 and 10). More than 80% of all applications were approved, and 65.4% of the patients underwent transplantation. Most importantly, none of these applicants met published guidelines for conditions justifying automatic exception points.4 There is no doubt that physicians should not be faulted for applying for exception points and acting on their patients' behalf. However, under the current system, these patients can apply for exception points and undergo transplantation with low MELD scores despite the substantial number of patients dying in areas of the country with significantly higher MELD scores. With a National Share 15 policy being considered, it is possible that this phenomenon of 15 MELD exception points may occur more frequently in the future if such a policy is enacted.
In 2005, the Share 15 policy was enacted with the goal of improving organ allocation to those more likely to derive a significant survival benefit from transplantation. Simulations suggested that this policy would decrease the number of transplants in patients with low MELD scores and benefit the entire population of waitlisted candidates. Unfortunately, these simulations could not predict changes in human behavior because the total number of patients undergoing transplantation nationally with laboratory MELD scores less than 15 at the time of transplantation were unchanged over time. Additionally, when region 9 is excluded, only 15 of the 55 OPOs are single-center OPOs. However, even though these centers represent a minority of the more than 100 liver transplant centers in the United States, half of the applicants for 15 MELD exception points were listed at 1 of these single-center OPOs. Although the data do not allow us to definitively determine all the reasons that these centers applied for 15 MELD exception points, this aspect of the data suggests that one motivation was to avoid the sharing of organs.
It is known that in some patients the physiological MELD score does not accurately represent waitlist mortality. The MELD Exception Study Group has helped to identify a few specific circumstances in which automatic exception points are recommended.4 However, when patients with hepatocellular carcinoma within the Milan criteria, metabolic disease, and hepatopulmonary syndrome are excluded, the granting of points to waitlisted candidates applying for exception points is based on a free-form narrative that is assessed by an RRB. There has been limited evidence-based guidance on how the more common reasons for applications should be approached. For example, there are few data supporting the idea that patients with cholestatic liver disease are currently disadvantaged by the MELD system,10 and patients with complications such as recurrent cholangitis should meet specific requirements in order to receive additional MELD points. Other conditions such as polycystic liver disease, however, are associated with quality of life improvements after liver transplantation, although they are not necessarily associated with an increased pretransplant mortality risk.11 These are, therefore, decisions that require careful evaluations because they may have important consequences; as demonstrated by Massie et al.,12 patients who receive exception points have a significantly lower risk of waitlist mortality and greater odds of transplantation. If these patients are not judiciously selected, they could potentially disadvantage others who remain waitlisted in areas with different exception point practices.
The increased use of 15 MELD exception points reflects the greater trend in the use of exception points overall in candidates waitlisted for liver transplantation.13 The data demonstrate a decrease in the number of patients undergoing transplantation with laboratory MELD scores less than 15 over time only when all exception point applicants are excluded. However, the total number of organ recipients with low MELD scores is unchanged since the inception of the Share 15 policy. This general trend in the use of exception points is likely the product of a variety of factors, such as an overall increase in disease severity for waitlisted candidates and an increase in the prevalence of hepatocellular carcinoma over time.
However, our research suggests that the specific increase in 15 MELD exception points may be more directly related to the Share 15 policy for 2 reasons. First, before January 1, 2005, there were only 5 applications for 15 MELD exception points, whereas there were 452 afterward, with the numbers progressively increasing over time. Second, 31% of the applications for 15 MELD exception points specifically requested points to make patients eligible for transplantation, to keep organs local, to gain access to regional organs, or to gain access to extended criteria donors. In reviewing these data, we find it difficult to argue that the rise in applications for 15 MELD exception points is not a direct product of the Share 15 policy.
This study also demonstrates that significant regional variations exist in the requests for MELD exception points under the Share 15 policy. To some extent, this is not surprising because in the regions with low MELD scores, obtaining a score of 15 might increase the probability of transplantation the most. This is especially true if exception points are sought with the specific aim of accessing extended criteria donor organs. Although it must be reiterated that physicians should not be blamed for attempting to provide comprehensive care for their patients, this could have important ramifications if a national Share 15 policy is created in the future. An increase in the trend of applying for 15 MELD exception points could further exacerbate these regional disparities in access to transplantation. Advocating for the best interests of an individual patient may conflict with efforts to improve the outcomes of waitlisted candidates as a group.
To promote fairness and equity in the allocation of organs, a more standardized approach should be used in the evaluation of exception point applications. For example, a national review board able to address requests from any part of the country could help to minimize the regional variations seen in the use of exception points. In addition, the development of more comprehensive guidelines for both the physicians applying for points and the review boards evaluating requests is needed, especially for the common reasons for exception point applications (eg, encephalopathy, ascites, and variceal bleeding). For patients with ascites or hepatic hydrothorax, our data suggest that 15 MELD exception points could be used effectively if a formal consideration of the MELD-Na score is included. Finally, more research is needed to better identify those conditions for which the MELD score does not adequately estimate waitlist mortality.
Interestingly, the majority of the patients who received 15 exception points underwent transplantation with MELD scores of 15 or less. This suggests that few additional exception points were granted and that the laboratory MELD score did not substantially increase between the time of application approval and the time of transplantation. In addition, the risk of death or waitlist removal was not significantly different between patients whose applications were approved and patients whose applications were denied. Thus, there may not have been significant progression of disease during this period, and patients were possibly given priority for transplantation when they did not actually have a significantly increased mortality risk. Finally, the average DRI of all patients receiving 15 exception points was not significantly different from the national average for all transplant patients (1.41, IQR = 1.13-1.73), and when an analysis was performed by region, the differences in the median DRIs did not reach statistical significance. This suggests that higher risk organs were not more frequently transplanted into these candidates.
This study has several limitations. First, the UNOS Standard Transplant Analysis and Research files from which the data were extrapolated may have contained incomplete data. However, unlike exception points for hepatocellular carcinoma, for these applications for 15 points to be reviewed by an RRB, a narrative for each patient is mandatory, so it is unlikely that significant information was missing from our data collection. Because these narratives were submitted to UNOS by individual transplant centers, the specifics of how each RRB determined which candidates should receive exception points are largely unknown: only the final decision was available for review. For example, many applications were submitted for more than 1 reason. Although we selected the primary reason in our review, we believe that for many applicants, combinations of factors were considered by the RRBs in determining whether points should be granted. Furthermore, it is likely that patients with multiple complications of cirrhosis have increased waitlist mortality, although this has not been widely studied. As for the patients with low laboratory MELD scores at transplant, it is possible that patients who received exception points still derived a significant survival benefit from liver transplantation and had a waitlist mortality risk that was different from the risk of the overall pool of candidates with low MELD scores. Although we can infer that the increase in the use of exception points since the creation of the Share 15 policy has potentially affected organ sharing, whether actual hazards exist as a result of this has yet to be determined. Finally, with respect to the socioeconomic differences in patients applying for 15 MELD exception points, neighborhood poverty was used as a surrogate, and it may not truly represent patients' socioeconomic data. Continued research efforts are needed to gain a more comprehensive understanding of the differences in the socioeconomic backgrounds of these patients.
We recognize that the total number of patients applying for 15 MELD exception points is small; however, we believe that the implications are significant for a number of reasons. First, there may be a greater risk associated with transplantation for patients with low MELD scores in comparison with remaining on the wait list. Second, the performance of transplantation for patients with low MELD scores and exception points, even in small numbers, diverts organs from waitlisted candidates with high MELD scores and the highest risk of waitlist mortality. Third, as mentioned previously, the use of 15 MELD exception points may increase if a national Share 15 policy is enacted. Lastly, the implications and scale of these data (60 patients per year) are similar to the potential impact of several other policies being strongly considered by the UNOS Liver and Intestinal Organ Transplantation Committee. The impact of limiting transplants in these patients with 15 MELD exception points (more than 30 transplants per year) is akin to the potential gains associated with the proposed national Share 15 policy, which could reduce waitlist deaths by 25 per year,14 or with the Regional Share 15 policy, which could prevent an additional 32 deaths per year.15 Therefore, because of the continued shortage of this therapeutic modality, it is paramount that organs be allocated by a system that equitably addresses both patients' needs and potential benefits. In providing this assessment of a specific aspect of organ sharing, we anticipate and encourage the continued evaluation of (and research into) both current and future liver transplant allocation policies.
In conclusion, the implementation of the UNOS Share 15 policy has given way to a marked increase in applications for 15 exception points. Although there is significant regional variability in the utilization of this practice, which may be partly explained by regional differences in median MELD scores at transplantation, there is currently no standardization of the review and point allocation process across, or even within, different regions. Most importantly, a number of patients continue to undergo transplantation with low MELD scores (many with the help of these additional exception points), and they may have a greater mortality risk as a result of transplantation. Without any interventions in the current state, there remains a risk of continued disparities in the allocation of organs in the United States. These issues will be heightened if a national sharing program is enacted without a process in place to systematically address the issue of exception points.