title: Relationship between HbA1c and continuous glucose monitoring in Chinese population: a multicenter study.
abstract: OBJECTIVE
  Since there is a paucity of reference data in the literature to indicate the relationship between HbA1c, and 24 h mean blood glucose (MBG) from continuous glucose monitoring (CGM) in Chinese populations, we described the above relationship in adult Chinese subjects with different glucose tolerance status.
  
  
  METHODS
  Seven-hundred-and-forty-two individuals without history of diabetes were included to the study at 11 hospitals in urban areas across China from 2007-2009 and data of 673 subjects were included into the final analysis. Oral glucose tolerance test (OGTT) classified the participants as nondiabetic subjects, including those with normal glucose regulation (NGR; n = 121) and impaired glucose regulation (IGR; n = 209), or newly diagnosed type 2 diabetes (n = 343). All participants completed testing for HbA1c levels and wore a CGM system for three consecutive days. The 24 h MBG levels were calculated. Spearman correlations and linear regression analyses were applied to quantify the relationship between glucose markers.
  
  
  RESULTS
  The levels of HbA1c and 24 h MBG significantly increased with presence of glucose intolerance (NGR<IGR<type 2 diabetes; both, P<0.001). Analysis of the total population indicated that HbA1c was strongly correlated with 24 h MBG (r = 0.735). The correlation was also found to be significant for the subgroup of participants with newly diagnosed type 2 diabetes (r = 0.694, P<0.001). Linear regression analysis of the total study population yielded the following equation: 24 h MBG(mmol/L )= 1.198×HbA1c-0.582 (24 h MBG(mg/dL )= 21.564×HbA1c-10.476) (R(2)= 0.670, P<0.001). The model fit was not improved by application of exponential or quadratic modeling. When HbA1c was 6.5%, the calculated 24 h MBG was 7.2 (6.4-8.1) mmol/L (130 (115-146) mg/dL); and when HbA1c was 7.0%, the 24 h MBG was 7.8 (6.9-8.7) mmol/L (140 (124-157) mg/dL).
  
  
  CONCLUSIONS
  Our study provided the reference data of the relationship between HbA1c and CGM in Chinese subjects.
authors.affiliation: Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Key Clinical Center for Metabolic Disease, Shanghai, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Key Clinical Center for Metabolic Disease, Shanghai, China.
authors.forename: Yifei
authors.initials: Y
authors.lastname: Mo
authors.affiliation: Department of Endocrinology and Metabolism, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Xingwu
authors.initials: X
authors.lastname: Ran
authors.affiliation: Department of Endocrinology and Metabolism, China-Japan Friendship Hospital, Beijing, China.
authors.forename: Wenying
authors.initials: W
authors.lastname: Yang
authors.affiliation: Department of Endocrinology and Metabolism, The Second Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated First People's Hospital, Shanghai, China.
authors.forename: Yongde
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Department of Endocrinology and Metabolism, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors.forename: Yanbing
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Endocrinology and Metabolism, Fudan University Affiliated Zhongshan Hospital, Shanghai, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Endocrinology and Metabolism, The First People's Hospital of Foshan, Foshan, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Luan
authors.affiliation: Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrinology and Metabolism, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Weiqing
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Diabetic Neurology, Metabolic Disease Hospital, Tianjin Medical University, Tianjin, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Clinical Center for Diabetes, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Key Clinical Center for Metabolic Disease, Shanghai, China.
authors.forename: Weiping
authors.initials: W
authors.lastname: Jia
mesh_terms: D001786:Blood Glucose / Q000032:analysis*; D002681:China; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000175:diagnosis; D005215:Fasting / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D012016:Reference Values
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin