Department of Internal Medicine, University of Michigan, Ann Arbor, MI; Arbor Research Collaborative for Health, Ann Arbor, MI. firstname.lastname@example.org.
Under an ideal implementation of Model for End-stage Liver Disease (MELD)-based liver allocation, the only factors that would predict DDLT rates are MELD score, blood type, and donation service area (DSA). We aimed to determine whether additional factors are associated with DDLT rates in actual practice. Methods: Data from the Scientific Registry of Transplant Recipients on all adult candidates waitlisted between 03/01/2002 and 12/31/2008 (n=57,503) were analyzed. Status-1 candidates were excluded. Cox regression was used to model covariate-adjusted DDLT rates, stratified by DSA, blood type, liver-intestine policy and allocation MELD. Inactive time on the waitlist was not modeled, such that the computed DDLT hazard ratios (HR) are interpreted as ""among actively listed candidates"". Results: Many factors, including candidate age, gender, prior DDLT, diagnosis, hospitalization status, height, and combined listing for liver-kidney and liver-intestine were significantly associated with DDLT rates. Factors associated with significantly lower covariate-adjusted DDLT rates were higher serum creatinine (HR=0.92; p<0.0001); higher bilirubin (HR=0.996; p=0.001), and receipt of dialysis (HR=0.83; p<0.0001). Mild ascites (HR=1.15; p<0.0001) and hepatic encephalopathy (Grade 1-2, HR=1.05; p=0.0236; grade 2-3, HR=1.10, p=0.0103) were associated with significantly higher adjusted DDLT rates. Conclusions: Adjusted DDLT rates among actively listed candidates are affected by many factors aside from those integral to the allocation system; including the components of the MELD score itself, as well as candidate factors that were considered but deliberately omitted from the MELD score in order to keep it objective. These results raise the question of whether additional candidate characteristics should be explicitly incorporated into the prioritization of wait list candidates; since such factors are already systematically affecting DDLT rates under the current allocation system. Liver Transpl, 2012. © 2012 AASLD.