Regional Variations in Peer Reviewed Liver Allocation Under the MELD System

Authors


*Corresponding author: Hugo E. Vargas, vargas.hugo@mayo.edu

Abstract

The Model for End-Stage Liver Disease (MELD) is used to assign priority for liver transplantation candidates. The Organ Procurement and Transplantation Network (OPTN) approved recognized exceptional diagnoses (RED's) for which MELD fails to accurately measure priority. Centers can request increased MELD points in cases not recognized by this policy (non-RED's). Our aim was to compare regional practices to justify non-RED requests for MELD adjustments. The UNOS/OPTN database was queried to extract all adult cases for which a non-RED MELD adjustment was requested from 2/27/02 until 8/27/03. The data were stratified by region and justification. Data for 29 510 listings were available. 26 947 had complete diagnosis information. There were 827 non-RED requests of which 477 (57.7%) petitions were approved by the regional review boards (RRBs). The approval rate varied significantly among regions (range: 28–75%, p < 0.0001). The most common non-RED's were complications of portal hypertension (48%). The percentage of patients listed with non-RED's varied significantly among regions (0.7–8.3 %, p < 0.0001), as did the proportion of patients transplanted with non-RED's (2.1–31.9%, p < 0.0001). Demographics did not differ among regions requesting non-REDs.Widespread regional variations exist in the handling of requests for non-REDs. These variations point to the need for reform to standard exception criteria.

Introduction

The adoption of the Model for End-Stage Liver Disease (MELD) to rank patients on the adult transplantation list followed extensive prospective and retrospective validation of a simple model that had many advantages over the previously used Child-Turcotte-Pugh (CTP) score (1–5). The MELD models use entirely objective parameters (bilirubin, International Normalized Ratio (INR), and serum creatinine) to calculate a robust predictor of mortality from liver disease. At the time of implementation, policymakers recognized that mortality risk, as defined by the MELD score, was not a good measure of liver transplant need for patients with hepatocellular carcinoma (HCC) (6). Similarly, patients with metabolic disorders and porto-pulmonary hypertension, in which the severity of liver dysfunction has little to do with disease progression, required a method for receiving priority above that conferred by their calculated MELD score. Regional Review Boards (RRB) were given the task of assessing centers requests for increased MELD scores for patients with these diagnoses. For candidates with HCC, the policy initially equated the 3-month risk of cancer progression to a 15 and 30% mortality risk for stage I and II disease, respectively. Stipulations for increased priority were also included in the MELD policy for the other RED of hepatopulmonary syndrome, oxalosis and familial amyloidosis because these patients do not have short-term mortality risks because of their liver disease despite having other comorbidities that increase their need for liver transplantation (5,7). In addition, the MELD policy allows centers to request increased MELD priority for other patients whom the center feels have a need for transplant that is greater than their mortality risk as estimated by their calculated MELD score. The RRB review all requests for increased MELD points for non-REDs.

No systematic review of the frequency, approval rates, characteristics, and regional variation for the non-RED requests within the MELD system has been published to date. Given the autonomy of each region to review these cases, it is important to know how many cases are subjected to review and how these adjustments impact the chances of these individuals to receive a life-saving graft and also how this process may affect the REDs and standard MELD patients. The aim of this study is to compare regional practices and to review the rationale used to justify non-RED MELD exceptions and examine how these results may affect the other patients waiting for liver transplantation.

Patients and Methods

The UNOS/OPTN scientific database was queried to extract all adult cases in which exceptions to MELD were requested for the period 27 February 2002 to 27 August 2003. Only non-REDs requests were considered. We collected demographics, calculated MELD score, and requesting diagnoses with supporting narratives were collected. The narratives were reviewed by two groups of clinicians and controversial cases were reviewed jointly for consensus. Patients were classified into one of 13 petition categories (Table 1). The data were stratified by UNOS region and justification for exception.

Table 1.  Most common justifications cited by centers in their petitions to RRBs for MELD score adjustments.
Diagnostic categoriesn
Ascites171
Porto-systemic encephalopathy94
Biliary complications90
Cholangitis89
Portal hypertensive bleeding72
Regional agreement62
Hepatic hydrothorax61
Worsening symptoms58
Malnutrition24
Concern for CCA21
Renal failure19
Cholangiocarcinoma (CCA)12
Other54

Statistics

Patient demographics, ABO group and petitioning status were compared by student's t-test or χ2 test where appropriate. Non-REDs per UNOS/OPTN region, distribution of patients per UNOS/OPTN regions, and number of petitions per UNOS/OPTN regions were analyzed using the χ2 test. For all analyses, a p value of ≤0.05 was considered statistically significant. Statistical analysis was performed using SAS software. (SAS Institute Inc., SAS Campus Drive, Cary, NC 27513, USA)

Results

Twenty-nine thousand five hundred and ten (29 510) listings were reviewed by UNOS during the study period. There were 3,281 petitions for upgrade of native MELD score of which 827 were for non-RED's. Of those, 479 were males. (NS) The ethnic distribution was 630 Caucasians, 96 Hispanics, 59 African-American, 29 Asians and 13 patients were listed as unknown. (p = NS) The ABO group distribution was O (410), A (294), B (104) and AB 19. (NS) The distribution of petitions for non-REDs per region varied significantly (range: 0.7–8.3%; p ≤ 0.001). We organized the data per region to highlight the difference in practice per RRB. Both absolute numbers of non-RED petitions and percentage of petitions from the total patients listed during this period varied significantly. (see Figure 1) For non-REDs petitions, 477 (58%) were granted, 311 (37%) were denied, and 39 (5%) were withdrawn for unknown reasons. (See Figure 2) The percentage of petitions approved varied significantly among regions (range: 28%–75%; p ≤ 0.001). The mean native MELD scores (defined as the score obtained without any adjustments) and the scores granted after review varied significantly among the regions as well (p ≤ 0.001) (Figure 3).

Figure 1.

Distribution of all RED and non-RED petitions by region. The percentage of non-RED patients listed in their region during that period of time is listed in italics and parenthesis below. There is significant regional difference in this practice (p < 0.001).

Figure 2.

Outcome of non-RED petitions in the period studied. Solid bars: total petitions, hatched bars: petitions approved, white bars: petitions denied. Petitions in process during the query period are listed as indeterminate (p < 0.001).

Figure 3.

Mean MELD scores for non-RED petitions in the different UNOS regions. Solid bars: native MELD, hatched: MELD requested, white bars: MELD score the time of transplantation (p ≤ 0.001).

Liver transplantation was more likely to occur in the 827 non-RED petitioned cases (granted or not) when compared to standard MELD patients. Of the non-REDs cases, 60% (489 patients) have been transplanted in the study period compared to only 22% of standard MELD patients listed (p = 0.02). The listing/transplantation ratio amongst no-exception, RED, and non-RED varied significantly among the OPTN regions. (p ≤ 0.001) (Figure 4). Patients who faced retransplantation were significantly more likely to be considered for non-RED exception (p < 0.001).

Figure 4.

Impact of upgrade in MELD score on transplant rate. The bars represent the number of liver transplants performed divided by the number listed in that region for patients with routine MELD (black bar), recognized exceptional diagnosis (hatched bars) and non-recognized exceptional diagnoses (white bars). p = 0.02.

Discussion

The present study focuses on the regional variations in practice of applying for and granting requests for increased MELD scores for non-REDs. We found in this large, carefully reviewed sample, regional practices for MELD adjustments that varied significantly. The increased use of liberal granting of non-REDs adjustments in some regions contributes to geographic differences in transplantation probabilities. One must conclude from our data that variations in these practice behaviors have an impact on who is transplanted. One notable example is that any patient for whom an exception to the calculated MELD scores was requested, whether the request was granted or not, was more likely to be transplanted compared with patients for whom no request was made.

One very clear strategy that centers are employing that is illuminated by our findings is the use of portal hypertension complications as a justifying factor for MELD exception. Our group found that five of the twelve most commonly used nonstandard exception appeals used in the study period were complications such as intractable ascites, hydrothorax, gastrointestinal bleeding and porto-systemic encephalopathy. These accounted for 48% of the non-REDs requests to the RRBs. However, portal hypertensive symptoms are purposefully absent from the MELD calculation. This is the result of extensive early testing of the model, which clearly demonstrated that these factors add little to the predictive power of MELD (3). Furthermore, eliminating the use of subjective measurements such as intractable ascites and encephalopathy in favor of robust, objective data is one of the merits of using MELD (4). Another surprising complication used to grant extra MELD points is renal failure. The MELD model weighs renal function very highly and appeals on the basis of renal dysfunction clearly constitute an over-compensation for these patients (5–10).

The ultimate clinical impact of this approach to patient care is that the clinicians in some regions are requesting additional priority for complications that have clearly been shown to not improve the MELD model's accuracy. This, in turn, translates to an increased likelihood of transplantation for those patients whose cases are favorably acted on by the RRBs. There is no question that the best individual to assess the severity of disease in a patient is the clinician at the bedside and we must respect that input, but we also must be good stewards of our nation's scarce resource and, therefore, we need to avoid application of nonscientific alterations in a system designed to use objective data to best allocate organs for transplantation.

As our data demonstrates, once a petition for higher MELD is accepted, the likelihood of receiving a graft increases dramatically. Since there are wide variations in the numbers of petitions requested among the regions, regional variations in transplant rates are affected by this variation in practice. If the aim of our national allocation system is a rational, regionally blind process where any individual, regardless of geographical origin can receive a fair review and be granted a MELD score that truly reflects the prognosis of his/her disease and a nationally agreed upon need for transplantation, we have to strive to achieve new methods to attain this goal. It is imperative for maintenance of the credibility of the system that more uniform requesting and accepting practices are employed for the exceptional request system within the MELD allocation policy.

How should the results of our study influence our practice? There are two simple steps that will improve the present system:

  • 1Form a national review committee whose sole function is to review requests for increased priority. The membership of this committee should include representation from all regions and individual case reviewers should not be allowed to review application from their own region. This committee can analyze the specific justifications for requests and look for situations in which the MELD does not adequately account for the patient's need for transplant. Through a more systematic and consistent collection of data, a national review committee could oversee studies to effectively use exceptional case adjustments in the most appropriate and fair manner.
  • 2The national committee should outline specific guidelines for non-REDs so that a patient with certain disease complications can receive the same relative adjustment irrespective of where he or she resides. These guidelines will go a long way in improving the present system.

Acknowledgments

The authors would like to thank Dr Eric Edwards and Ms Ann Harper for their contribution to this study.

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