Associated balance of risk score -- comprehensive complication index for the prediction of long-term survival after liver transplantation: starting from the ABC

Iesari, Samuele [UCL] Lai, Quirino Melandro, Fabio Nowak, Greg Nicolini, Daniele Zanus, Giacomo Ciccarelli, Olga [UCL] Vivarelli, Marco Cillo, Umberto Rossi, Massimo Ericzon, Bo-Göran Lerut, Jan [UCL] et al.[show all]

Background: In past years, several scoring systems were developed to predict early post-LT graft function. However, many of them showed poor accuracy in predicting long-term survival. Moreover, the majority of available scores are composed of many evasive variables, making user-friendly predictive models hard to generate. Recently, the pre-transplant Balance of Risk (BAR) and the post-LT Comprehensive Complication Index (CCI) have been created. However, external validation and integration of the two scores in liver transplantation is absent. This study aims to produce a user-friendly scoring system based on the combination of a low number of pre- and immediately post-liver transplant (LT) independent variables, in order to accurately predict long-term graft survival after LT. Methods/Materials: A Training Set was created, composed of 1,262 retrospectively analysed first-LT performed in four European Centres (Brussels, Rome Sapienza, Ancona and Padua). A Validation Set from the Karolinska Institute (N=520) was also obtained, for external validation of the results coming from the Training Set. Results: The Associated Balance of risk-Comprehensive complication index (ABC) was generated in the Training Set, based on the combination of HCV status, BAR and CCI. At internal validation, the ABC showed the best discriminative power for the risk of five-year graft loss, with an area under the curve (AUC)=0.80. The external validation confirmed the good accuracy of the score (AUC=0.70). Conclusions: The ABC score shows excellent predictive power for five-year graft survival, and its accuracy is greater than several pre-transplant (i.e. MELD, D-MELD, BAR) and post-transplant scores (i.e. CCI and Early Allograft Dysfunction score) (ClinicalTrials.gov NCT03723317).