title: Prevalence of prediabetes and diabetes and metabolic profile of patients with nonalcoholic fatty liver disease (NAFLD).
abstract: OBJECTIVE
  Prediabetes and type 2 diabetes mellitus (T2DM) are believed to be common and associated with a worse metabolic profile in patients with nonalcoholic fatty liver disease (NAFLD). However, no previous study has systematically screened this population.
  
  
  METHODS
  We studied the prevalence and the metabolic impact of prediabetes and T2DM in 118 patients with NAFLD. The control group comprised 20 subjects without NAFLD matched for age, sex, and adiposity. We measured 1) plasma glucose, insulin, and free fatty acid (FFA) concentration during an oral glucose tolerance test; 2) liver fat by magnetic resonance spectroscopy (MRS); 3) liver and muscle insulin sensitivity (euglycemic insulin clamp with 3-[(3)H]glucose); and 4) indexes of insulin resistance (IR) at the level of the liver (HIR(i)= endogenous glucose production × fasting plasma insulin [FPI]) and adipose tissue (Adipo-IR(i)= fasting FFA × FPI).
  
  
  RESULTS
  Prediabetes and T2DM was present in 85% versus 30% in controls (P < 0.0001), all unaware of having abnormal glucose metabolism. NAFLD patients were IR at the level of the adipose tissue, liver, and muscle (all P < 0.01-0.001). Muscle and liver insulin sensitivity were impaired in patients with NAFLD to a similar degree, whether they had prediabetes or T2DM. Only adipose tissue IR worsened in T2DM and correlated with the severity of muscle (r = 0.34; P < 0.001) and hepatic (r = 0.57; P < 0.0001) IR and steatosis by MRS (r = 0.35; P < 0.0001).
  
  
  CONCLUSIONS
  Patients with NAFLD may benefit from early screening for T2DM, because the prevalence of abnormal glucose metabolism is much higher than previously appreciated. Regardless of glucose tolerance status, severe IR is common. In patients with T2DM, adipose tissue IR appears to play a major role in the severity of NAFLD.
authors.affiliation: Division of Diabetes, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
authors.forename: Carolina
authors.initials: C
authors.lastname: Ortiz-Lopez
authors.forename: Romina
authors.initials: R
authors.lastname: Lomonaco
authors.forename: Beverly
authors.initials: B
authors.lastname: Orsak
authors.forename: Joan
authors.initials: J
authors.lastname: Finch
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chang
authors.forename: Valeria G
authors.initials: VG
authors.lastname: Kochunov
authors.forename: Jean
authors.initials: J
authors.lastname: Hardies
authors.forename: Kenneth
authors.initials: K
authors.lastname: Cusi
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D048909:Diabetes Complications / Q000097:blood / Q000453:epidemiology / Q000378:metabolism; D003920:Diabetes Mellitus / Q000097:blood / Q000453:epidemiology* / Q000378:metabolism; D005234:Fatty Liver / Q000097:blood / Q000150:complications / Q000453:epidemiology* / Q000378:metabolism*; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000150:complications / Q000453:epidemiology / Q000378:metabolism; D008297:Male; D055442:Metabolome / Q000502:physiology; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease; D009765:Obesity / Q000097:blood / Q000150:complications / Q000453:epidemiology / Q000378:metabolism; D050177:Overweight / Q000097:blood / Q000150:complications / Q000453:epidemiology / Q000378:metabolism; D011236:Prediabetic State / Q000097:blood / Q000150:complications / Q000453:epidemiology* / Q000378:metabolism; D015995:Prevalence