title: Significance of oral glucose tolerance tests in non-alcoholic fatty liver disease patients with a fasting plasma glucose level of <126 mg/dL and HbA1c level of ≤ 6.4% in Japan.
abstract: OBJECTIVE
  The aim of this study was to clarify the indications for oral glucose tolerance tests (OGTT) in non-alcoholic fatty liver disease (NAFLD) subjects with a HbA1c level of ≤6.4%, fasting plasma glucose (FPG) level of <126 mg/dL and no history of diabetes.
  
  
  METHODS
  A total of 569 NAFLD subjects underwent 75-g OGTT. The plasma glucose and insulin levels were analyzed periodically for three hours during the OGTT examinations. Impaired fasting glucose (IFG) was defined as a plasma glucose level of ≥100 mg/dL to <126 mg/dL. Diabetes was defined as a two-hour post-load plasma glucose level of ≥200 mg/dL. Elevated insulin resistance was defined as a homeostasis model assessment-insulin resistance (HOMA-IR) of ≥2.5. Insulin secretory insufficiency was defined as an insulinogenic index of <0.4.
  
  
  RESULTS
  The prevalence of diabetes on the OGTT was 7.7% (44/569) among the NAFLD patients with an HbA1c level of ≤6.4%, FPG level of <126 mg/dL and no history of diabetes. A multivariate analysis showed that diabetes occurred more frequently when the subjects had IFG [odds ratio (OR) 5.13; 95% confidential interval (CI) 3.01-8.76; p<0.001] and an HbA1c level of 5.7-6.4% (OR 5.45; 95% CI 3.33-8.93; p<0.001). Of the NAFLD subjects with both IFG and an HbA1c level of 5.7-6.4%, 22.8% (28/123) exhibited a pattern of diabetes on OGTT. Regarding insulin dynamics, among the NAFLD subjects with both IFG and an HbA1c level of 5.7-6.4%, 25.2% (31/123) had elevated IR alone, 25.2% (31/123) had insulin secretory deficiency alone and 27.6% (34/123) had both elevated insulin resistance and insulin secretory deficiency.
  
  
  CONCLUSIONS
  NAFLD subjects with IFG and an HbA1c level of 5.7-6.4% should undergo OGTT in order to determine whether they have diabetes and/or abnormal insulin dynamics.
authors: Department of Health Management Center and Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Japan.
authors: Naoki
authors: N
authors: Matsumoto
authors: Yasuji
authors: Y
authors: Arase
authors: Yusuke
authors: Y
authors: Kawamura
authors: Miki
authors: M
authors: Ohmoto-Sekine
authors: Kazuhisa
authors: K
authors: Amakawa
authors: Kyoko
authors: K
authors: Ogawa
authors: Hiroshi
authors: H
authors: Tsuji
authors: Hsieh Shiun
authors: HS
authors: Dong
authors: Shigeko
authors: S
authors: Hara
authors: Norio
authors: N
authors: Akuta
authors: Fumitaka
authors: F
authors: Suzuki
authors: Yoshiyuki
authors: Y
authors: Suzuki
authors: Kenji
authors: K
authors: Ikeda
authors: Hiromitsu
authors: H
authors: Kumada
authors: Tetsurou
authors: T
authors: Kobayashi
mesh_terms: D000368:Aged; D044466:Asian People; D001786:Blood Glucose; D003920:Diabetes Mellitus / Q000097:blood / Q000175:diagnosis*; D005215:Fasting / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000097:blood*; D011236:Prediabetic State / Q000175:diagnosis; D015995:Prevalence
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007328:Insulin