title: Assessing 1-h plasma glucose and shape of the glucose curve during oral glucose tolerance test.
abstract: OBJECTIVE
  To assess the cutoff values at different time points for impaired glucose regulation (IGR) and diabetes, the glucose curve and isolated 1-h hyperglycemia were monitored during an oral glucose tolerance test (OGTT).
  
  
  METHODS
  Two thousand eight hundred and eighty-six subjects (1300 men and 1586 women) were recruited to have an OGTT. Plasma was collected at 0, 30, 60, 120, and 180 min to analyze glucose and insulin. The diagnosis of impaired fasting glucose, impaired glucose tolerance, and diabetes was based on World Health Organization and American Diabetes Association's criteria. Those with fasting plasma glucose (FPG) < 5.6 and 2-h plasma glucose (PG) < 7.8, but 1-h PG > or = 7.8 and < 11.1 mmol/l were defined as 1h-High7.8, and those with FPG < 7.0 and 2-h PG < 11.1, but 1-h PG > or =11.1 mmol/l as 1h-High11.1. The cutoff values were calculated by receiver operating characteristic (ROC) curve. The correlation between beta-cell function and the area under the curve of glucose (AUCg) and the shape index was analyzed with linear regression.
  
  
  RESULTS
  The cutoff values for IGR were 5.6, 9.7, 10.1, 7.8 and 6.1 mmol/l for blood glucose at 0, 30, 60, 120 and 180 min, 24 for AUCg and 1.3 mmol/l for the shape index. The cutoff values for diabetes were 6.8, 11.2, 13, 11.1 and 7 mmol/l for 0, 30, 60, 120 and 180 min, 30.9 for AUCg and 2 mmol/l for the shape index. Both AUCg and the shape index were inversely related to beta-cell function. The profiles of glucose and insulin in the subgroup with isolated 1-h hyperglycemia were very different from those seen in subjects with normal glucose tolerance or IGR.
  
  
  CONCLUSIONS
  The present study provides new information on measures other than the fasting and 2-h PG to evaluate glucose metabolism in vivo and stimulates further research aimed at assessing the value of the OGTT 1-h PG concentration prospectively.
authors.affiliation: Department of Endocrinology, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine (SJU-SM, formerly Shanghai Second Medical University), 197, Ruijin 2nd Road, Shanghai 200025, China.
authors.forename: Weibin
authors.initials: W
authors.lastname: Zhou
authors.forename: Yanyun
authors.initials: Y
authors.lastname: Gu
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Luo
mesh_terms: D000328:Adult; D000886:Anthropometry; D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism*; D005260:Female; D018149:Glucose Intolerance / Q000378:metabolism; D005951:Glucose Tolerance Test; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism; D007328:Insulin / Q000097:blood; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D011236:Prediabetic State / Q000175:diagnosis / Q000378:metabolism; D012372:ROC Curve
chemical_list: D001786:Blood Glucose; D007328:Insulin