Better Performance of Fasting Plasma Glucose than Hemoglobin A_(1c) in Diagnosing Pre-Diabetes in Chinese Adolescents

Objective To examine the diagnostic values of American Diabetes Association(ADA)-recommended(2010) hemoglobin A1c(HbA1c) as criterion in diagnosing pre-diabetes among adolescents.Methods A total of 933 junior and senior middle school students(aged 13～16 yr;46.5% females) without known diabetes were randomly selected through cluster and stratified sampling from Liaoyang,a moderately developed northeast city.All participants completed questionnaires and underwent examination of vital signs,HbA1c,FPG,and some other biochemical indices.Pre-diabetes was diagnosed according to 2010 ADA criteria[HbA1c 5.7%～6.4% or FPG(5.6～6.9)mmol/L].Pre-diabetes individuals willing to receive further examinations(n=91) underwent OGTT.The concordance between first screening results and OGTT results was evaluated for HbA1c and FPG,respectively.Results Of the 213(22.8%)individuals diagnosed as pre-diabetes,roughly two thirds[72.3%(154/213)] were identified by HbA1c alone and one third[23.0%(49/213)] were identified by FPG alone,with only 4.7%(10/213) were identified by both tests simultaneously.The ROC curve for FPG to identify increased HbA1c had an area under the curve(AUC) of 0.56(P=0.023),while AUC of HbA1c to identify increased FPG showed no statistical significance(P=0.970).In OGTT,among the 68 individuals with increased HbA1c in first screening,only 18(26.5%) were confirmed to be IGT or IFG;among the 27 individuals with increased FPG in first screening,20(74.1%) were diagnosed as IGT or IFG;coincidence rates of the HbA1c group and the FPG group were significantly different(P0.01).Individuals with increased HbA1c(ADA 2010 criteria) and normal glucose tolerance(WHO 1999 criteria) showed higher levels of waist hip ratio,triglyceride,total cholesterol,uric acid and lower levels of female ratios than individuals with normal HbA1c and FPG(all P0.05).Conclusion In Chinese adolescents,FPG performs better than HbA1c in the diagnosis and screening of pre-diabetes,but HbA1c is,to some extent,related to abnormal metabolism in adolescents.