title: C-Peptide-Based Index Is More Related to Incident Type 2 Diabetes in Non-Diabetic Subjects than Insulin-Based Index.
abstract: BACKGROUND
  Diabetes can be efficiently prevented by life style modification and medical therapy. So, identification for high risk subjects for incident type 2 diabetes is important. The aim of this study is to identify the best β-cell function index to identify high risk subjects in non-diabetic Koreans.
  
  
  METHODS
  This is a retrospective longitudinal study. Total 140 non-diabetic subjects who underwent standard 2-hour 75 g oral glucose tolerance test from January 2007 to February 2007 at Kangbuk Samsung Hospital and followed up for more than 1 year were analyzed (mean follow-up, 54.9±16.4 months). The subjects were consist of subjects with normal glucose tolerance (n=44) and subjects with prediabetes (n=97) who were 20 years of age or older. Samples for insulin and C-peptide levels were obtained at 0 and 30 minutes at baseline.
  
  
  RESULTS
  Thirty subjects out of 140 subjects (21.4%) developed type 2 diabetes. When insulin-based index and C-peptide-based index are compared between progressor and non-progressor to diabetes, all C-peptide-based indices were statistically different between two groups, but only insulinogenic index and disposition index among insulin-based index were statistically different. C-peptide-based index had higher value of area under receiver operating characteristic curve (AROC) value than that of insulin-based index. "C-peptidogenic" index had highest AROC value among indices (AROC, 0.850; 95% confidence interval, 0.761 to 0.915). C-peptidogenic index had significantly higher AROC than insulinogenic index (0.850 vs. 0.731 respectively; P=0.014).
  
  
  CONCLUSIONS
  C-peptide-based index was more closely related to incident type 2 diabetes in non-diabetic subjects than insulin-based index.
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, Konyang University Hospital, Konyang University College of Medicine, Daejeon, Korea.
authors.forename: Jong Dai
authors.identifier: http://orcid.org/0000-0002-2606-3646
authors.initials: JD
authors.lastname: Kim
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, Konyang University Hospital, Konyang University College of Medicine, Daejeon, Korea.
authors.forename: Sung Ju
authors.initials: SJ
authors.lastname: Kang
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, Myongji Hospital, Seonam University College of Medicine, Goyang, Korea.
authors.forename: Min Kyung
authors.initials: MK
authors.lastname: Lee
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Se Eun
authors.initials: SE
authors.lastname: Park
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Rhee
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Cheol Young
authors.initials: CY
authors.lastname: Park
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Ki Won
authors.initials: KW
authors.lastname: Oh
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Park
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea. wonyoung2.lee@samsung.com.
authors.forename: Won Young
authors.identifier: http://orcid.org/0000-0002-1082-7592
authors.initials: WY
authors.lastname: Lee
keywords: C-peptide; Glucose tolerance test; Insulin secretion and incident diabetes