Predicting post-liver transplantation mortality: a retrospective cohort study on risk factor identification and prognostic nomogram construction.

Background: To identify risk factors for post-transplant mortality and develop a machine learning-integrated prognostic tool to optimise clinical decision-making in liver transplantation (LT) recipients.

Methods: This retrospective cohort study analysed 173 allogeneic LT recipients at the Affiliated Hospital of Zunyi Medical University between August 2019 and December 2023. Clinical and biochemical variables were systematically collected, including recipient profiles [age, gender, prior abdominal surgery Performance Status (PS) scores], biochemical markers (serum creatinine, sodium, albumin, total bilirubin, neutrophil/lymphocyte counts), and prognostic scores [Model for End-Stage Liver Disease (MELD), MELD-sodium (MELD-Na), Child-Turcotte-Pugh (CTP), neutrophil-to-lymphocyte ratio (NLR), and albumin-bilirubin (ALBI)]. Intraoperative metrics, such as blood loss volume and anhepatic phase duration, were also recorded. Univariate and multivariate Cox regression identified mortality predictors. LASSO-regularised Cox regression facilitated variable selection and nomogram construction. Internal validation used decision curve analysis (quantifying clinical net benefit) and time-dependent receiver operating characteristic (ROC) curve analysis [12/18/24-month area under the curve (AUC)]. Kaplan-Meier survival analysis stratified patients into tertiles.

Results: Univariate analysis identified MELD score > 25, blood loss > 5 L, PS score, neutrophil count, total bilirubin level, and MELD-Na score as significant predictors (p < 0.05). Multivariate Cox regression confirmed massive haemorrhage (> 5 L) as an independent mortality predictor (p < 0.001). LASSO-selected predictors (prior abdominal surgery, blood loss > 5 L, and ALBI score) formed a prognostic nomogram demonstrating strong discrimination (1-year AUC: 0.824; 2-year AUC: 0.788). Tertile-based stratification revealed significant intergroup differences in survival (p < 0.001).

Conclusions: Massive intraoperative haemorrhage independently predicted post-LT mortality. The validated nomogram integrating surgical history, haemorrhage severity, and ALBI score enables clinically actionable risk stratification, potentially informing perioperative resource allocation and personalised management protocols.