title: The diagnostic threshold of HbA1c and impact of its use on diabetes prevalence-a population-based survey of 6898 Han participants from southern China.
abstract: OBJECTIVE
  The objective of this study is to determine the diagnostic threshold of HbA1c for diabetes and the impact of using it on diabetes prevalence.
  
  
  METHODS
  A population-based stratified study was conducted in 2010 among community-dwelling adults aged ≥35years in southern China. Participants without previously-diagnosed diabetes (PDD) took oral glucose tolerance test (OGTT) and HbA1c assay. HbA1c diagnostic threshold was determined by receiver operating characteristic curve.
  
  
  RESULTS
  A total of 6989 participants with mean age of 52years were recruited. The area under curve of HbA1c was 0.903 (95% CI: 0.883-0.922), with optimal cut-off value at 6.25% (sensitivity 75.6% and specificity 91.9%). There were 449 (6.42%) patients with PDD and 422 (6.04%), 815 (11.66%) and 918 (13.13%) new cases diagnosed by OGTT, HbA1c ≥6.25% or either, respectively. When either HbA1c or OGTT was used, newly-diagnosed diabetes prevalence increased by 117.4%.
  
  
  CONCLUSIONS
  Diabetes is prevalent in southern China. Near half of the patients go undetected with current diagnostic criteria. HbA1c ≥6.25% may be the diagnostic threshold value but needs further verification. The introduction of HbA1c threshold into diabetes diagnosis in China will cause a substantial increase in diabetes prevalence and great challenge on the public healthcare system.
authors.affiliation: Department of Cardiology, Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University, Guangzhou 510120, China; Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Guangzhou 510120, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Huang
authors.forename: Guicheng
authors.initials: G
authors.lastname: Peng
authors.forename: Maohuan
authors.initials: M
authors.lastname: Lin
authors.forename: Kun
authors.initials: K
authors.lastname: Zhang
authors.forename: Yifang
authors.initials: Y
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Yang
authors.forename: Zhiyi
authors.initials: Z
authors.lastname: Zuo
authors.forename: Renhua
authors.initials: R
authors.lastname: Chen
authors.forename: Jingfeng
authors.initials: J
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012372:ROC Curve; D012016:Reference Values; D012680:Sensitivity and Specificity
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: 2-hour plasma glucose; 2h-PG; AUC; BMI; CHD; DBP; Diabetes mellitus; Diagnosis; FPG; HDL-C; Hemoglobin A1c; LDL-C; NDD; NPV; OGTT; PDD; PPV; Public health; ROC; SBP; Southern China; TC; Threshold value; WHR; areas under the curve; body mass index; coronary heart disease; diastolic blood pressure; fasting plasma glucose; high density lipoprotein cholesterol; low density lipoprotein cholesterol; negative predictive value; newly-detected diabetes; oral glucose tolerance test; positive predictive value; previously-diagnosed diabetes; receiver operating characteristic; systolic blood pressure; total cholesterol; waist–hip ratio