title: The intravenous insulin tolerance test is an accurate method for screening a general population for insulin resistance and related abnormalities.
abstract: To verify whether the short intravenous insulin tolerance test (ITT) (a safe, reproducible, inexpensive, rapid and easy to perform measurement of insulin sensitivity) is a suitable test for insulin resistance screening in a general population, we measured in 60 non diabetic subjects, either non-obese (no.=40) or obese (BMI>28, no.=20) the K of glucose disappearance from plasma after ITT (K(ITT)), plasma glucose (PG) and insulin (IRI) both fasting (FPG, FIRI) and at 120 min of OGTT (PG- 120, IRI- 120), and also triglycerides (Tg), cholesterol (Chol) and blood pressure (BP). Subjects were subdivided into quartiles according to K(ITT) values. Average FPG, PG-120, FIRI, IRI-120, Tg and Chol values were progressively increased, and average HDL/Chol was progressively decreased from quartile 1 (the most insulin sensitive) to 4 (the most insulin resistant) (p<0.05, by 1-way ANOVA test). Also BP was increased in the insulin resistant patients, but statistical significance was not reached. Three or more of the studied parameters (FPG and/or PG-120, FIRI and/or IRI-120, Tg, HDL/Chol, mean BP) were altered (below the worst 25 degree percentile) in 64% of subjects from quartile 4; none of the subjects in quartile 1 was affected by such a cluster of alterations. K(ITT) values < or =4.8 identified the cluster of insulin resistance related alterations with an accuracy of 82% (sensitivity=83.3%, specificity=80.5%). In healthy subjects with a wide range of BMI the ITT is a reliable procedure for screening for the cluster of metabolic alterations related to insulin resistance.
authors.affiliation: Institute of Internal Medicine, Endocrine and Metabolic Disease, University of Catania, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Graci
authors.forename: R
authors.initials: R
authors.lastname: Baratta
authors.forename: C
authors.initials: C
authors.lastname: Degano
authors.forename: A
authors.initials: A
authors.lastname: Luppa
authors.forename: R
authors.initials: R
authors.lastname: Vigneri
authors.forename: L
authors.initials: L
authors.lastname: Frittitta
authors.forename: V
authors.initials: V
authors.lastname: Trischitta
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood; D007004:Hypoglycemic Agents; D007328:Insulin; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin