title: Pre-type 1 diabetes dysmetabolism: maximal sensitivity achieved with both oral and intravenous glucose tolerance testing.
abstract: OBJECTIVE
  To determine the relationship of intravenous (IVGTT) and oral (OGTT) glucose tolerance tests abnormalities to diabetes development in a high-risk pre-diabetic cohort and to identify an optimal testing strategy for detecting preclinical diabetes.
  
  
  METHODS
  Diabetes Prevention Trial-Type 1 Diabetes (DPT-1) randomized subjects to oral (n = 372) and parenteral (n = 339) insulin prevention trials. Subjects were followed with IVGTTs and OGTTs. Factors associated with progression to diabetes were evaluated.
  
  
  RESULTS
  Survival analysis revealed that higher quartiles of 2-hour glucose and lower quartiles of first phase insulin response (FPIR) at baseline were associated with decreased diabetes-free survival. Cox proportional hazards modeling showed that baseline body mass index (BMI), FPIR, and 2-hour glucose levels were significantly associated with an increased hazard for diabetes. On testing performed within 6 months of diabetes diagnosis, 3% (1/32) had normal FPIR and normal 2-hour glucose on OGTT. The sensitivities for impaired glucose tolerance (IGT) and low FPIR performed within 6 months of diabetes diagnosis were equivalent (76% vs 73%).
  
  
  CONCLUSIONS
  Most (97%) subjects had abnormal IVGTTs and/or OGTTs before the development of diabetes. The highest sensitivity is achieved using both tests.
authors.affiliation: Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, CO 80262, USA. jennifer.barker@uchsc.edu
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Barker
authors.forename: Kim
authors.initials: K
authors.lastname: McFann
authors.forename: Leonard C
authors.initials: LC
authors.lastname: Harrison
authors.forename: Spiros
authors.initials: S
authors.lastname: Fourlanos
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Krischer
authors.forename: David
authors.initials: D
authors.lastname: Cuthbertson
authors.forename: H Peter
authors.initials: HP
authors.lastname: Chase
authors.forename: George S
authors.initials: GS
authors.lastname: Eisenbarth
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism*; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D005947:Glucose / Q000008:administration & dosage; D005951:Glucose Tolerance Test / Q000379:methods; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000150:complications; D016016:Proportional Hazards Models; D015203:Reproducibility of Results; D013549:Sweetening Agents / Q000008:administration & dosage
chemical_list: D001786:Blood Glucose; D013549:Sweetening Agents; D005947:Glucose