title: Role of glycated hemoglobin in the prediction of future risk of T2DM.
abstract: OBJECTIVE
  The aim of this study was to assess the predictive power of glycated hemoglobin (HbA1c) for future type 2 diabetes risk.
  
  
  METHODS
  Six hundred eighty-seven subjects who were free of type 2 diabetes mellitus (T2DM) participated in the study. Each subject received a 75-g oral glucose tolerance test at baseline and 624 received a repeat oral glucose tolerance test after 3.5 ± 0.1 yr of follow-up. Anthropometric measurements, lipid profile, and HbA1c were measured during the baseline visit. Logistic multivariate models were created with T2DM status at follow-up as the dependent variable and other parameters as the independent variables. The receiver-operating characteristic (ROC) was used to assess the predictive discrimination of the various models.
  
  
  RESULTS
  HbA1c was a significant predictor of future T2DM risk (area under the ROC curve = 0.73, P < 0.0001). A HbA1c cut point of 5.65% had the maximal sum of sensitivity and specificity. Although the area under the ROC curve of HbA1c was smaller than the area under the ROC curve of both the 1-h plasma glucose concentration and a multivariate logistic model (including anthropometric parameters, lipid profile, and fasting plasma glucose), the addition of HbA1c to both the 1-h plasma glucose and the multivariate logistic model significantly increased their predictive power.
  
  
  CONCLUSIONS
  Although HbA1c alone is a weaker predictor of future T2DM risk compared with the 1-h plasma glucose, it provides additive information about future T2DM risk when added to previously published prediction models.
authors.affiliation: Division of Diabetes, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA. abdulghani@uthscsa.edu
authors.forename: Muhammad A
authors.initials: MA
authors.lastname: Abdul-Ghani
authors.forename: Tamam
authors.initials: T
authors.lastname: Abdul-Ghani
authors.forename: Gabriele
authors.initials: G
authors.lastname: Müller
authors.forename: Antje
authors.initials: A
authors.lastname: Bergmann
authors.forename: Sabine
authors.initials: S
authors.lastname: Fischer
authors.forename: Stefan
authors.initials: S
authors.lastname: Bornstein
authors.forename: Ralph A
authors.initials: RA
authors.lastname: Defronzo
authors.forename: Peter
authors.initials: P
authors.lastname: Schwarz
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000453:epidemiology* / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D012372:ROC Curve; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human