Association between Triglyceride-Glucose Index and Risk of Sepsis-Associated Liver Injury and Mortality in Critically Ill Patients: A Retrospective Cohort Study

Background The triglyceride-glucose (TyG) index, a surrogate marker of insulin resistance, has been implicated in metabolic dysregulation and adverse clinical outcomes. However, its association with sepsis-associated liver injury (SALI) and mortality in critically ill patients remains unclear. This study aimed to investigate the association between the TyG index and SALI risk, as well as all-cause mortality in intensive care unit (ICU) patients. Methods A retrospective cohort study was conducted using data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Critically ill patients with complete TyG index measurements were included. The primary outcome was SALI incidence, and secondary outcomes included in-hospital, ICU, 28-day, 90-day, and 365-day mortality. Logistic and cox multivariate regression analyses and restricted cubic spline were applied to evaluate associations. Results Among 4343 patients 10.7% developed SALI. In-hospital, ICU, 28-day, 90-day, and 365-day mortality rates were 15.6%, 11.1%, 18.4%, 23.2%, and 28.8%, respectively. A linear positive association was observed between the TyG index and SALI risk [adjusted OR (95% CI) 1.52 (1.12~2.08), P -value 0.008]. For mortality, a nonlinear association was identified with TyG index and in-hospital mortality (P for nonlinearity=0.014), with an inflection point at TyG index=9.888. Below this threshold, each TyG index unit increase was associated with higher in-hospital mortality [HR 1.86 (1.49–2.34)， P <0.001], whereas no significant association was observed above it [HR 1.22 (0.76–1.97)]. The subgroup analysis suggests that our results are robust. Conclusions Elevated TyG index was an independent risk factor for SALI in critically ill patients and demonstrated a nonlinear association with in-hospital mortality. These findings highlight TyG as a practical biomarker for risk stratification and targeted management in the ICU setting.