title: Measuring β-cell function relative to insulin sensitivity in youth: does the hyperglycemic clamp suffice?
abstract: OBJECTIVE
  To compare β-cell function relative to insulin sensitivity, disposition index (DI), calculated from two clamps (2cDI, insulin sensitivity from the hyperinsulinemic-euglycemic clamp and first-phase insulin from the hyperglycemic clamp) with the DI calculated from the hyperglycemic clamp alone (hcDI).
  
  
  METHODS
  Complete data from hyperglycemic and hyperinsulinemic-euglycemic clamps were available for 330 youth: 73 normal weight, 168 obese with normal glucose tolerance, 57 obese with impaired glucose tolerance, and 32 obese with type 2 diabetes. The correlation between hcDI and 2cDI and Bland-Altman analysis of agreement between the two were examined.
  
  
  RESULTS
  Insulin sensitivity and first-phase insulin from hcDI showed a hyperbolic relationship. The hcDI correlated significantly with 2cDI in the groups combined (r = 0.85, P < 0.001) and within each group separately (r ≥ 62, P < 0.001). Similar to 2cDI, hcDI showed a declining pattern of β-cell function across the glucose-tolerance groups. Overall, hcDI values were 27% greater than 2cDI, due to the hyperglycemic versus euglycemic conditions, reflected in a positive bias with Bland-Altman analysis.
  
  
  CONCLUSIONS
  β-Cell function relative to insulin sensitivity could be accurately evaluated from a single hyperglycemic clamp, obviating the need for two separate clamp experiments, when lessening participant burden and reducing research costs are important considerations.
authors.affiliation: Division of Weight Management and Wellness, Children’s Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Lindsey
authors.initials: L
authors.lastname: Sjaarda
authors.forename: SoJung
authors.initials: S
authors.lastname: Lee
authors.forename: Hala
authors.initials: H
authors.lastname: Tfayli
authors.forename: Fida
authors.initials: F
authors.lastname: Bacha
authors.forename: Marnie
authors.initials: M
authors.lastname: Bertolet
authors.forename: Silva
authors.initials: S
authors.lastname: Arslanian
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D015309:Glucose Clamp Technique / Q000379:methods*; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D050417:Insulin-Secreting Cells / Q000502:physiology*; D008297:Male
chemical_list: D007328:Insulin