Reduced short-term survival following liver transplant in patients with acute-on-chronic liver failure: Reevaluating OPTN data.

BACKGROUND

Prior studies show severe acute-on-chronic liver failure (ACLF) at liver transplantation (LT) negatively impacts short-term, but not long-term, post-LT outcomes. However, not accounting for ACLF's time-varying effect on the waitlist may underappreciate its dynamic nature. Moreover, excluding those who died or dropped off the waitlist raises concerns about selection bias.

METHODS

This US nationwide retrospective cohort study estimated the effect of severe ACLF (grade 3) (ACLF-3) on post-LT outcomes, including adult, first-time deceased donor LT candidates listed from June 2013 to May 2023. A marginal structural model (MSM) to address selection bias and time-varying exposure (ACLF-3) was applied, with extended Cox proportional hazard models using a Heaviside step function to assess the hazard of death after LT.

RESULTS

Among 31,267 eligible candidates for LT (baseline cohort), 11.3% (n = 3518) had ACLF-3 at listing; 13.6% (n = 4243) died or dropped out while on the LT waitlist. Of the 27,024 patients who received LT (transplanted cohort), 12.3% (n = 3333) had ACLF-3 at LT. ACLF-3 at LT (but not at waitlisting) was associated with a higher hazard of death, with the hazard ratio of 1.80 (95% CI: 1.09-2.97) within 1 year after LT but not thereafter. This marginal structural model effect size was 9% higher than conventional multivariable Cox proportional hazard models. Sensitivity analyses corroborated these findings.

CONCLUSIONS

Compared to previous studies, ACLF-3 at LT in our marginal structural model was associated with a discernible increase in short-term mortality after transplant, presumably due to our addressing of selection bias, while long-term survival was similar to those without severe ACLF at LT. However, potential vulnerability to posttransplant complications warrants further investigation.