Higher Waitlist Mortality in Pediatric Acute-on-chronic Liver Failure in the UNOS Database

Acute-on-chronic liver failure (ACLF), whereas increasingly well-defined in adults, has been poorly characterized in pediatric patients other than having a poor prognosis. This study aimed to identify ACLF and evaluate prognosis in the American pediatric population.

Modified ACLF definitions (p-CLIF) were applied to 11,300 children listed for liver transplantation from March 2002 through 2017 in the Organ Procurement and Transplantation Network (OPTN) database.

Pediatric ACLF patients have greater mortality within 90 days from listing (46.6% by p-CLIF) than other types of failure (<30%), including acute liver failure, as well as greater mortality within the first 30 and 90 days after transplantation than all other types of liver failure, but do not have increased mortality rates relative to other groups between 90 and 365 days from transplant. Although some ACLF listings also received 1B status, ACLF mortality at 90 days was greater than the general 1B population (50 vs 29.4%). Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease scores of ACLF patients are lower than 1B listings, and do not predict waitlist or posttransplant death. Greater number of organ failures does correlate with increased mortality. Biliary atresia is the leading etiology of pediatric chronic liver disease, accounting for over 30% of chronic and 45% of ACLF listings, yet is protective against mortality (hazard ratio [HR] = 0.142 for ACLF). Receiving exception approval is independently but similarly protective in ACLF (HR = 0.145).

These findings pose a challenge for allocation decisions but indicate greater attention to ACLF is needed, as scoring systems may not capture these children's risk of early death, which appears to currently be mitigated by exceptions. Multicenter, clinical, preferably prospective study of ACLF is necessary to determine how to prioritize ACLF relative to other liver failure types to address its relatively higher early mortality.