Pre-type 1 diabetes dysmetabolism: maximal sensitivity achieved with both oral and intravenous glucose tolerance testing.
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.
Barker
Jennifer M
JM
Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, CO 80262, USA. jennifer.barker@uchsc.edu
McFann
Kim
K
Harrison
Leonard C
LC
Fourlanos
Spiros
S
Krischer
Jeffrey
J
Cuthbertson
David
D
Chase
H Peter
HP
Eisenbarth
George S
GS
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
D001786:Blood Glucose; D013549:Sweetening Agents; D005947:Glucose