Status 1B designation does not adequately prioritize children with acute-on-chronic liver failure for liver transplantation.

Acute-on-chronic liver failure (ACLF) is an acute decompensation of chronic liver disease leading to multiorgan failure and mortality. The objective of this study was to evaluate characteristics and outcomes of children with ACLF who are at the highest priority for liver transplantation (LT) on the United Network for Organ Sharing (UNOS) database-listed as status 1B. The characteristics and outcomes of 478 children with ACLF listed as status 1B on the UNOS LT waiting list from 2007-2019 were compared with children with similar or higher priority listing for transplant: 929 with acute liver failure (ALF) listed as status 1A and 808 with metabolic diseases and malignancies listed as status 1B (termed "non-ACLF"). Children with ACLF had comparable rates of cumulative organ failures compared with ALF (45% vs. 44%; p > 0.99) listings, but higher than non-ACLF (45% vs. 1%; p < 0.001). ACLF had the lowest LT rate (79%, 84%, 95%; p < 0.001), highest pre-LT mortality (20%, 11%, 1%; p < 0.001), and longest waitlist time (57, 3, 56 days; p < 0.001), and none recovered without LT (0%, 4%, 1%; p < 0.001). In survival analyses, ACLF was associated with an increased adjusted hazard ratio (HR) for post-LT mortality (HR, 1.50 vs. ALF [95% confidence interval, CI, 1.02-2.19; p = 0.04] and HR, 1.64 vs. non-ACLF [95% CI, 1.15-2.34; p = 0.01]). ACLF has the least favorable waitlist and post-LT outcomes of all patients who are status 1A/1B. Increased prioritization on the LT waiting list may offer children with ACLF an opportunity for enhanced outcomes.