title: Association of Alanine Aminotransferase Levels (ALT) with the Hepatic Insulin Resistance Index (HIRI): a cross-sectional study.
abstract: BACKGROUND
  The association between serum alanine aminotransferase (ALT) levels and hepatic insulin resistance (IR) has been evaluated with the hyperinsulinemic-euglycemic clamp. However, there is no information about the association of ALT with the Hepatic Insulin Resistance Index (HIRI). The aim of this study was to evaluate the association between serum ALT levels and HIRI in subjects with differing degrees of impaired glucose metabolism.
  
  
  METHODS
  This cross-sectional study included subjects that had an indication for testing for type 2 diabetes mellitus (T2DM) with an oral glucose tolerance test (OGTT). Clinical and biochemical evaluations were carried out including serum ALT level quantification. HIRI was calculated for each participant. Correlation analyses and lineal regression models were used to evaluate the association between ALT levels and HIRI.
  
  
  RESULTS
  A total of 324 subjects (37.6% male) were included. The mean age was 40.4 ± 14.3 years and the mean body mass index (BMI) was 32.0 ± 7.3 kg/m2. Individuals were divided into 1 of 5 groups: without metabolic abnormalities (n = 113, 34.8%); with the metabolic syndrome (MetS, n = 179, 55.2%), impaired fasting glucose (IFG, n = 85, 26.2%); impaired glucose tolerance (IGT, n = 91, 28.0%), and T2DM (n = 23, 7.0%). The ALT (p < 0.001) and HOMA2-IR (p < 0.001) values progressively increased with HIRI quartiles, while ISI-Matsuda (p < 0.001) progressively decreased. After adjustment for sex, age, and BMI, we identified a significant correlation between HIRI and ALT in persons with the MetS (r = 0.22, p = 0.003), IFG (r = 0.33, p < 0.001), IGT (r = 0.37, p < 0.001), and T2DM (r = 0.72, p < 0.001). Lineal regression analysis adjusting for age, HDL-C, TG and waist circumference (WC) showed an independent association between ALT and HIRI in subjects with the MetS (beta = 0.07, p = 0.01), IFG (beta = 0.10, p = 0.02), IGT (beta = 0.09, p = 0.007), and T2DM (beta = 0.31, p = 0.003). This association was not identified in subjects without metabolic abnormalities.
  
  
  CONCLUSIONS
  ALT levels are independently associated with HIRI in subjects with the MetS, IFG, IGT, and T2DM. The ALT value in these subjects may be an indirect parameter to evaluate hepatic IR.
authors.affiliation: Department of Internal Medicine, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", Vasco de Quiroga # 15, Sección XVI Tlalpan, 14000 Mexico City, Mexico. alfonso.guliash@quetzal.innsz.mx.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Gómez-Sámano
authors.forename: Daniel
authors.initials: D
authors.lastname: Cuevas-Ramos
authors.forename: Roopa
authors.initials: R
authors.lastname: Mehta
authors.forename: Hasan
authors.initials: H
authors.lastname: Brau-Figueroa
authors.forename: Clara Elena
authors.initials: CE
authors.lastname: Meza-Arana
authors.forename: Alfonso
authors.initials: A
authors.lastname: Gulias-Herrero