Impact of Model for End-stage Liver Disease Cutoffs on Liver Transplant Access in the United States: A Regression Discontinuity Design

BACKGROUND: Since Share-35 and continuing under the Acuity Circle (AC) policy, US liver transplant (LT) allocation has relied on Model for End-Stage Liver Disease (MELD) thresholds that may distort fair and seamless access.

METHODS: We analyzed adult LT candidates listed from January 2016 to June 2024. Regression discontinuity analysis using Poisson regression for top-5 offer rates and discrete-time hazard regression for transplant rates and waitlist mortality estimated policy effects at a MELD score of 35 (MELD-35; Share-35) and MELD scores of 33 and 37 (MELD 33/37; AC). Secondary analyses were used to analyze the offer decline rates and donor characteristics at each MELD threshold.

RESULTS: In total, 98 896 candidates were analyzed. During Share-35, crossing the MELD-35 threshold was associated with significant increases in offers (rate ratio [RR], 3.39; 95% confidence interval [CI], 3.22-3.57) and transplants (odds ratio [OR], 2.13; 95% CI, 1.89-2.41). Under AC, smaller but significant effects were observed at MELD-37 (RR, 1.37; 95% CI, 1.31-1.44; OR, 1.15; 95% CI, 1.01-1.30) and at MELD-33 (RR, 1.48; 95% CI, 1.21-1.38 and OR, 1.16; 95% CI, 1.03-1.30). Candidates with an MELD score <37 experienced significantly higher waitlist mortality (OR, 0.40; 95% CI, 0.24-0.67). Secondary analyses showed higher decline rates at MELD-35 under Share-35, but lower rates at MELD 33/37 under AC with reduced marginal donor use.

CONCLUSIONS: MELD thresholds continue to influence LT access and donor quality/selection, creating artificial discontinuities and unintended disparity that misalign allocation with true disease severity. These findings support avoiding rigid score-based cutoffs not only in future US allocation models (eg, continuous distribution), but also in broader international allocation frameworks moving forward.