Association Between Lactate Levels upon ICU Admission After Liver Transplantation and the Burden of In-Hospital Complications: A Retrospective Cohort Study

Background: ICU-admission lactate after liver transplantation (LT) may reflect perioperative stress, but its association with cumulative morbidity remains unclear. Methods: This retrospective cohort included 457 adults undergoing first LT between October 2015 and July 2026. ICU-admission lactate was evaluated in four prespecified strata (<2, 2–<5, 5–<10, ≥10 mmol/L). Outcomes included the Comprehensive Complication Index (CCI), adapted early allograft dysfunction (EAD), Toronto graft dysfunction, MEAF, and death or retransplantation at 7 and 30 days. Analyses included multivariable regression, ROC analysis, and bootstrap validation. Results: Strata comprised 178, 210, 51, and 18 recipients. Median CCI increased from 29.6 to 89.3 (p < 0.001). After adjustment, the ≥10 mmol/L group had a 40.1-point higher median CCI than the <2 mmol/L group (95% CI 27.1–53.0). Adapted EAD increased from 24.2% to 83.3%, and severe Toronto dysfunction from 0.6% to 61.1%. Seven-day death or retransplantation increased from 0% to 61.1% (adjusted HR per lactate doubling 2.83, 95% CI 2.15–3.72; AUC 0.869). Adding lactate increased the 30-day AUC from 0.691 to 0.800 (optimism-corrected: 0.652 to 0.767). Conclusions: ICU-admission lactate was associated with postoperative morbidity and early adverse outcomes, supporting risk stratification pending external validation.