Data on the interaction between ACLF and MELD score in predicting waitlist (WL) mortality in patients with cirrhosis are scarce. Thus, Mohamed Abdallah and coworkers
analysed the UNOS database, from 01/2002 to 06/2018, on liver transplantation (LT) listings for adult patients with cirrhosis and ACLF. In 18,416 candidates with ACLF at listing, 90-day WL mortality, defined as patient death or too sick for LT, was 21.6% (18%, 20%, 25%, and 39% for ACLF grades 1, 2, 3a, and 3b respectively). Using a Fine and Gray regression model, the authors identified an interaction between MELD and ACLF grade, with higher impact of ACLF at lower MELD score. A score, developed using parameter estimates from the interaction model on a derivation cohort (n = 9,181), was used to stratify a validation cohort (n = 9,235) into 4 quartiles: Q1 (score <10.42), Q2 (10.42–12.81), Q3 (12.82–15.50), and Q4 (>15.50). WL mortality increased with each quartile from 13%, 18%, 23%, and 36%, respectively. Observed vs
. expected deciles on WL mortality in the validation cohort showed good calibration (goodness of fit p
= 0.98) and correlation (r = 0.99). Thus, the authors concluded that, among selected candidates with ACLF at listing, MELD score and ACLF interact in predicting cumulative risk of 90-day WL mortality
, with higher impact of ACLF grade at lower listing MELD score.