We (Now) Know What We Are, But Not What We May Be

BACKGROUND: The OPTN implemented Share35 on 6/18/2013 to broaden deceased-donor liver sharing within regional boundaries. We investigated whether increased sharing under Share35 impacted geographic disparity in deceased-donor liver transplantation (DDLT) across Donation Service Areas (DSAs). METHODS: Using SRTR 6/2009-6/2017, we identified 86,083 adult LT candidates and retrospectively estimated MELD-adjusted DDLT rates using nested multilevel Poisson regression with random intercepts for DSA and transplant program. From the variance in DDLT rates across 49 DSAs and 102 programs, we derived the DSA-level median incidence rate ratio (MIRR) of DDLT rates. MIRR is a robust metric of heterogeneity across each hierarchical level; larger MIRR indicates greater disparity. RESULTS: MIRR was 2.18 pre-Share35 and 2.16 post-Share35. Thus, two candidates with the same MELD in two different DSAs were expected to have a 2.2-fold difference in DDLT rate driven by geography alone. After accounting for program-level heterogeneity, MIRR was attenuated to 2.10 pre-Share35 and 1.96 post-Share35. For candidates with MELD 15-34, MIRR decreased from 2.51 pre- to 2.27 post-Share35, and for candidates with MELD 35-40, MIRR increased from 1.46 pre- to 1.51 post-Share35, independent of program-level heterogeneity in DDLT. DSA-level heterogeneity in DDLT rates was greater than program-level heterogeneity pre- and post-Share35. CONCLUSIONS: Geographic disparity substantially impacted DDLT rates before and after Share35, independent of program-level heterogeneity and particularly for candidates with MELD 35-40. Despite broader sharing, geography remains a major determinant of access to deceased-donor liver transplantation.