title: Utility of hemoglobin A(1c) for diagnosing prediabetes and diabetes in obese children and adolescents.
abstract: OBJECTIVE
  Hemoglobin A(1c) (A1C) has emerged as a recommended diagnostic tool for identifying diabetes and subjects at risk for the disease. This recommendation is based on data in adults showing the relationship between A1C with future development of diabetes and microvascular complications. However, studies in the pediatric population are lacking.
  
  
  METHODS
  We studied a multiethnic cohort of 1,156 obese children and adolescents without a diagnosis of diabetes (male, 40%/female, 60%). All subjects underwent an oral glucose tolerance test (OGTT) and A1C measurement. These tests were repeated after a follow-up time of ∼2 years in 218 subjects.
  
  
  RESULTS
  At baseline, subjects were stratified according to A1C categories: 77% with normal glucose tolerance (A1C <5.7%), 21% at risk for diabetes (A1C 5.7-6.4%), and 1% with diabetes (A1C >6.5%). In the at risk for diabetes category, 47% were classified with prediabetes or diabetes, and in the diabetes category, 62% were classified with type 2 diabetes by the OGTT. The area under the curve receiver operating characteristic for A1C was 0.81 (95% CI 0.70-0.92). The threshold for identifying type 2 diabetes was 5.8%, with 78% specificity and 68% sensitivity. In the subgroup with repeated measures, a multivariate analysis showed that the strongest predictors of 2-h glucose at follow-up were baseline A1C and 2-h glucose, independently of age, ethnicity, sex, fasting glucose, and follow-up time.
  
  
  CONCLUSIONS
  The American Diabetes Association suggested that an A1C of 6.5% underestimates the prevalence of prediabetes and diabetes in obese children and adolescents. Given the low sensitivity and specificity, the use of A1C by itself represents a poor diagnostic tool for prediabetes and type 2 diabetes in obese children and adolescents.
authors.affiliation: Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA.
authors.forename: Paulina
authors.initials: P
authors.lastname: Nowicka
authors.forename: Nicola
authors.initials: N
authors.lastname: Santoro
authors.forename: Haibei
authors.initials: H
authors.lastname: Liu
authors.forename: Derek
authors.initials: D
authors.lastname: Lartaud
authors.forename: Melissa M
authors.initials: MM
authors.lastname: Shaw
authors.forename: Rachel
authors.initials: R
authors.lastname: Goldberg
authors.forename: Cindy
authors.initials: C
authors.lastname: Guandalini
authors.forename: Mary
authors.initials: M
authors.lastname: Savoye
authors.forename: Paulina
authors.initials: P
authors.lastname: Rose
authors.forename: Sonia
authors.initials: S
authors.lastname: Caprio
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis*; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D008297:Male; D009765:Obesity / Q000150:complications*; D011236:Prediabetic State / Q000175:diagnosis*
chemical_list: D015415:Biomarkers; D006442:Glycated Hemoglobin