Profile of liver enzymes in non-alcoholic fatty liver disease in patients with impaired glucose tolerance and newly detected untreated type 2 diabetes

CONTEXT: The perception of non-alcoholic fatty liver disease (NAFLD) as an uncommon and benign condition is rapidly changing. Approximately, 70% type 2 diabetes mellitus (T2DM) patients have a fatty liver, which may follow an aggressive course with necroinflammation and fibrosis. AIMS: To assess the profile of liver enzymes in subjects with impaired glucose tolerance (IGT), new onset treatment naive T2DM and normal glucose tolerance (NGT) with and without NAFLD. SETTINGS AND DESIGN: Cross-sectional clinic-based study. SUBJECTS AND METHODS: 152 IGT and 158 recently detected T2DM subjects aged between 30 and 69 years, along with 160 age and gender matched controls with NGT. An ultrasonography scan of the upper abdomen was done in all patients in order to examine presence of fatty liver. Anthropometry, lipid profile, liver enzymes were also analyzed in all patients. STATISTICAL ANALYSIS USED: Unpaired t-test, Chi-square/Fisher Exact test (for categorical variables), Pearson/Spearmen correlation test to find significant difference, association and correlation between two or more groups respectively. RESULTS: NAFLD was significantly associated with higher alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) but not ALP levels in IGT and T2DM patients. ALT, GGT significant correlated with waist circumference, body mass index, fasting insulin, homeostatic model assessment- insulin resistance, fasting blood glucose, high density lipoprotein cholesterol, triglyceride. 57% of NAFLD patients had normal ALT between 25 and 40 U/L, 53% of NAFLD subjects had normal GGT between 15 and 30 U/L. ALT <25 U/L and GGT <15 U/L had highest negative predictivity whereas ALT >40 U/L and GGT > 30 U/L had highest positive predictivity for presence of NAFLD in our study sample. CONCLUSIONS: Mild elevations of liver enzymes in the upper normal range are associated with features of metabolic syndrome and NAFLD even in IGT and recently detected T2DM patients. Novel cut-offs for liver enzymes are warranted in order to prevent unnecessary diagnostic work-ups and early detection of NAFLD to reduce the risk of cirrhosis, hepatocellular carcinoma and classical cardiovascular disease in T2DM and IGT patients.