Diagnostic accuracy of serum alanine aminotransferase as biomarker for nonalcoholic fatty liver disease and insulin resistance in healthy subjects, using 3T MR spectroscopy

Abstract

Recognition of the close relationship of nonalcoholic fatty liver disease (NAFLD) with diabetes mellitus 2, obesity, metabolic syndrome, and cardiovascular disease has stimulated growing interest in NAFLD as a public health problem. Serum alanine aminotransferase (ALT) has been proposed as a marker of NAFLD, but levels are within the range currently considered “normal” in a large proportion of NAFLD subjects.The aim of the study was to determine the diagnostic accuracy of serum ALT for identifying individuals with NAFLD, using 3-Tesla (T) magnetic resonance spectroscopy (1H-MRS).A cross-sectional study was conducted in 129 healthy subjects. Liver triglyceride content was quantified by 1H-MRS. NAFLD was defined as liver triglyceride content greater than 5.56%.Liver triglyceride content was >5.56% in 79 participants (NAFLD) and lower in the remaining 50 (normal). Serum ALT levels correlated positively with liver triglyceride content (r = 0.58, P < .001), Homeostatic Model Assessment for Insulin Resistance (r = 0.32, P < .01), and fasting insulin (r = 0.31, P < .01), and inversely correlated with adiponectin (r = 0.35, P < .01) and high-density lipoprotein cholesterol (r = 0.32, P < .01). Regression analysis showed that serum ALT was the best predictor of NAFLD (P < .01). Optimal serum ALT cut-off to predict NAFLD was 23 IU/L (area under receiver-operating characteristic curve: 0.93; sensitivity: 0.94; specificity: 0.72).This study shows that serum ALT is a sensitive and accurate biomarker of NAFLD if the “normal” ALT value is revised and established at a lower level. An ALT threshold of 23 IU/L identified 94% of individuals with NAFLD in the present series, using 3-T 1H-MRS for liver triglyceride quantification.

Proportion of NAFLD patients with normal ALT value in overall NAFLD patients: a systematic review and meta-analysis

“…NAFLD is usually caused by the abnormal metabolism in patients and tightly associated with dyslipidemia, diabetes mellitus and obesity [5]. Abundant studies and clinical practices have proven that the liver enzyme levels such as ALT and so on were increased usually in the NAFLD patients, and these liver enzymes could be used as the diagnostic markers for the NAFLD at some extent [29][30][31]. However, not all the studies supported the above conclusion.…”

Enhanced GIP Secretion in Obesity Is Associated with Biochemical Alteration and miRNA Contribution to the Development of Liver Steatosis

“…Martin-Rodriguez et al (2017) showed a correlation of ALT with liver fat content and increased insulin resistance, suggesting that ALT, even when within the normal range, may be useful for NAFLD categorization when evaluating NAFLD's systemic relationships. This study shows that optimal serum ALT cut-off to predict NAFLD is 23 IU/L [47], although there is no general consensus on the upper reference limit of ALT (40 IU/l is the most common in medical practice). A study on obese patients showed that elevated ALT and GGT levels correlated significantly with the incidence of steatohepatitis and fibrosis [48].…”

Association of alanine transaminase to aspartate aminotransferase ratio and incident diabetes in Chinese adults: a second retrospective cohort study

“…Besides, former researches have con rmed that hepatic diseases like non-alcoholic fatty liver disease (NAFLD) were related to glucose metabolism and the prevalence of diabetes (21,22). And the elevation of liver enzymes such as ALT, AST and gammaglutamyl transpeptidase (GGT) or the ALT/AST ratio are treated as surrogate markers of NAFLD in common (23)(24)(25). Monami, M., et al have a rmed a undeniable relation between elevated liver enzyme levels and type 2 diabetes (T2DM) (26).…”