Optimal cutoff values of alanine aminotransferase and its derived markers for pediatric MASLD.

Background: The early detection of metabolic dysfunction-associated steatotic liver disease (MASLD) is essential. This study aims to evaluate the diagnostic utility and optimal cutoffs of alanine aminotransferase (ALT) and its derived markers, including the ALT/aspartate aminotransferase (AST) and ALT/high-density lipoprotein cholesterol (HDL) ratios, for predicting pediatric MASLD. Methods: We analyzed data from 1,158 adolescents in the National Health and Nutritional Examination Survey (NHANES) and 263 adolescents from a real-world clinical cohort. MASLD was assessed using vibration-controlled transient elastography in the NHANES cohort and abdominal ultrasonography in the clinical cohort. Logistic regression and receiver operating characteristic (ROC) curve analyses were conducted to evaluate associations and predictive performance. Results: ALT, ALT/AST, and ALT/HDL were significantly associated with MASLD in both datasets, even after adjusting for age and sex (all p < 0.001). In the NHANES cohort, the areas under the ROC curves (AUCs) for ALT, ALT/AST, and ALT/HDL were 0.73, 0.77, and 0.76, respectively, with optimal cutoff values of >14.50 for ALT, >0.74 for ALT/AST, and >0.29 for ALT/HDL in the total population. In the real-world clinical cohort, the corresponding AUCs were 0.84, 0.84, and 0.86, respectively. ALT/HDL demonstrated the highest AUC in both datasets, reaching 0.92 in females in the clinical cohort. Conclusions: ALT and ALT-derived markers are valuable for predicting pediatric MASLD. Among them, the ALT/HDL ratio demonstrated the best predictive performance, indicating that composite indices integrating markers of hepatic injury and metabolic status may enhance early detection of MASLD in children and adolescents.