Admission Liver Enzyme Elevation Grade for Risk Stratification in Critically Ill Patients: Development and Internal Validation of an Exploratory Prognostic Model.

Background

Liver enzyme abnormalities are common in critically ill patients, but the prognostic relevance of graded aminotransferase elevation and its timing remains uncertain. We evaluated whether Liver Enzyme Elevation (LEE) grade at ICU admission provides prognostic information beyond SAPS II in a heterogeneous ICU cohort.

Methods

In this single-centre retrospective study, adult patients admitted to a mixed ICU between January 2023 and December 2024 and with ICU length of stay ≥72 h were analysed. LEE grade was assigned from AST and ALT according to predefined multiples of the local upper limit of normal, using the higher grade reached by either enzyme. The primary outcome was ICU mortality. Secondary outcomes included renal replacement therapy, ICU length of stay, and duration of invasive mechanical ventilation. A fixed logistic model including SAPS II and admission LEE grade was internally validated by bootstrap resampling.

Results

Among 274 patients, ICU mortality was 27.7%. Admission LEE grade showed an adjusted association with ICU mortality (OR 1.26 per grade increase, 95% CI 1.00-1.58; p = 0.048), while SAPS II remained the dominant predictor (OR 1.04 per point, 95% CI 1.02-1.06; p < 0.001). Adding admission LEE grade to SAPS II yielded a small absolute increase in discrimination (AUC 0.737 vs. 0.703; DeLong p = 0.039). Bootstrap-corrected AUC was 0.730, with acceptable overall calibration. Admission LEE grade was also associated with RRT and longer ICU stay in exploratory secondary analyses.

Conclusions

Admission LEE grade may provide modest complementary prognostic information beyond SAPS II. These findings are exploratory and require external validation before clinical implementation.