title: Update of the German Diabetes Risk Score and external validation in the German MONICA/KORA study.
abstract: OBJECTIVE
  Several published diabetes prediction models include information about family history of diabetes. The aim of this study was to extend the previously developed German Diabetes Risk Score (GDRS) with family history of diabetes and to validate the updated GDRS in the Multinational MONItoring of trends and determinants in CArdiovascular Diseases (MONICA)/German Cooperative Health Research in the Region of Augsburg (KORA) study.
  
  
  METHODS
  We used data from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study for extending the GDRS, including 21,846 participants. Within 5 years of follow-up 492 participants developed diabetes. The definition of family history included information about the father, the mother and/or sibling/s. Model extension was evaluated by discrimination and reclassification. We updated the calculation of the score and absolute risks. External validation was performed in the MONICA/KORA study comprising 11,940 participants with 315 incident cases after 5 years of follow-up.
  
  
  RESULTS
  The basic ROC-AUC of 0.856 (95%-CI: 0.842-0.870) was improved by 0.007 (0.003-0.011) when parent and sibling history was included in the GDRS. The net reclassification improvement was 0.110 (0.072-0.149), respectively. For the updated score we demonstrated good calibration across all tenths of risk. In MONICA/KORA, the ROC-AUC was 0.837 (0.819-0.855); regarding calibration we saw slight overestimation of absolute risks.
  
  
  CONCLUSIONS
  Inclusion of the number of diabetes-affected parents and sibling history improved the prediction of type 2 diabetes. Therefore, we updated the GDRS algorithm accordingly. Validation in another German cohort study showed good discrimination and acceptable calibration for the vast majority of individuals.
authors.affiliation: Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany; German Center for Diabetes Research, Germany.
authors.forename: Kristin
authors.initials: K
authors.lastname: Mühlenbruch
authors.affiliation: Institute of Epidemiology II, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research, Germany.
authors.forename: Tonia
authors.initials: T
authors.lastname: Ludwig
authors.affiliation: Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany; German Center for Diabetes Research, Germany.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Jeppesen
authors.affiliation: Department of Pharmacology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany; German Center for Diabetes Research, Germany.
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Joost
authors.affiliation: Institute of Biometry and Epidemiology, German Diabetes Center, Düsseldorf, Germany; German Center for Diabetes Research, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Rathmann
authors.affiliation: Institute of Epidemiology II, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Meisinger
authors.affiliation: Institute of Epidemiology II, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Peters
authors.affiliation: Department of Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
authors.forename: Heiner
authors.initials: H
authors.lastname: Boeing
authors.affiliation: Institute of Epidemiology II, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Thorand
authors.affiliation: Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany; German Center for Diabetes Research, Germany. Electronic address: mschulze@dife.de.
authors.forename: Matthias B
authors.initials: MB
authors.lastname: Schulze
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D002318:Cardiovascular Diseases / Q000209:etiology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D005858:Germany / Q000453:epidemiology; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: Receiver operating characteristic; Reclassification; Risk assessment; Type 2 Diabetes mellitus; Validation study