A High Alanine Aminotransferase/Aspartate Aminotransferase Ratio Determines Insulin Resistance and Metabolically Healthy/Unhealthy Obesity in a General Adult Population in Korea: The Korean National Health and Nutritional Examination Survey 2007-2010

AIMS: Early identification of individuals with insulin resistance (IR) and metabolically unhealthy state can help prevent various diseases and improve quality of life. In this study, we investigated a possible marker of IR and metabolic health status, alanine aminotransferase/aspartate aminotransferase (ALT/AST) ratio, and aimed to confirm its feasibility in a large population study. METHODS: A total of 16,371 adults from Korean National Health and Examination Survey were studied. Participants were divided into four groups according to their ALT/AST ratio quartiles. The homeostatic model assessment of insulin resistance level and proportion of people with IR, impaired fasting glucose, and undiagnosed type 2 diabetes were compared for each group. Receiver-operating characteristics (ROC) curve was also used to assess the usefulness of ALT/AST ratio to identify individuals with IR and metabolically unhealthy. RESULTS: In the groups with higher ALT/AST ratio, HOMA-IR level, proportion of IR, and proportion of individuals with IFG or type 2 diabetes mellitus was higher than that in those with low ALT/AST ratio. When analyzed with other factors related to IR, the data showed that the ALT/AST ratio was an independent predictor of IR (odds ratio 1.363, 95% confidential interval 1.323-1.405, p<0.001). When ROC curve analysis was done, area under curve (AUC) for identifying individuals with IR was 0.634. In addition, metabolically unhealthy individuals showed significantly higher ALT/AST ratio than metabolically healthy individuals (0.9780 vs 0.8511, p