Defining a Liver Transplant Benefit Threshold for the Model for End-Stage Liver Disease-Sodium Score

Objectives: The benefits of transplant are shown as the difference in survival posttransplant versus that shown if the patient had remained on the wait list. Serum sodium was added to improve prediction. We sought to revisit the question of which Model for End-Stage Liver Disease-Sodium score threshold corresponded to a predicted benefit of liver transplant. Materials and Methods: Data on adult patients (>= 18 years old) were obtained from the United Network for Organ Sharing registry (date range of June 18, 2013 to December 2016). Exclusion criteria were individuals listed for multiple organs or liver retransplant, patients who eventually underwent living-donor liver transplant, and patients with MELD score < 12. We used multivariable Cox proportional hazards regression to determine a time-dependent covariate for undergoing transplant with either MELD or MELD-sodium scores to describe the variability in estimated transplant benefit within 6 months of listing. Results: Our study included 14352 patients. There were 902 patients with MELD score of 39 to 40 (6.3%) and 931 patients with MELD-Na score of 39 to 40 (6.5%). Using the original MELD score, we found that 90% of the cohort could derive benefit from transplant compared with 83% when MELD-Na was used. We found that 13% of patients had a predicted transplant benefit when determined using either MELD or MELD-Na but not both. The threshold for transplant benefit was 16 and 17 using MELD and MELD-Na, respectively. Conclusions: Transition to MELD-Na did not define a more precise range at which patients benefited from transplant, and a similar percentage of patients was expected to derive benefit. Future revisions of donor liver allocation may allow better discrimination of expected transplant benefits among candidates currently assigned a high priority for donor livers.