The short insulin tolerance test lacks validity in adolescents with Type 1 diabetes.
OBJECTIVE
The short insulin tolerance test (SITT) has been found to be a simple and valid method for determining insulin sensitivity in healthy adults and patients with Type 2 diabetes. In this study we evaluated the reproducibility and validity of SITT in 16 adolescents with Type 1 diabetes.


METHODS
Thirteen patients underwent two SITT and eight patients were examined with both SITT and a euglycaemic hyperinsulinaemic clamp. At the SITT insulin sensitivity was measured from the slope of arterialized blood glucose concentrations determined for 16 min after an intravenous bolus injection of short-acting insulin, 0.1 U/kg body weight, and expressed as glucose disappearance rate (KITT).


RESULTS
There was a significant correlation between the insulin sensitivity estimations made at the two SITT (r = 0.73, P = 0.003). The reproducibility was low, however, with a coefficient of variation of 38.7%. KITT showed a strong inverse correlation to the fasting blood glucose concentration (r = -0.74, P < 0.0001). We found no correlation between insulin sensitivity measured by SITT and that measured by the euglycaemic clamp.


CONCLUSIONS
We conclude that the short insulin tolerance test cannot be used in adolescent patients with Type 1 diabetes for a simple estimation of insulin sensitivity.
Särnblad
S
S
Department of Paediatrics, Orebro Medical Centre Hospital, Orebro, Sweden. stefan.sarnblad@orebroll.se
Kroon
M
M
Aman
J
J
D000293:Adolescent; D000328:Adult; D001774:Blood Chemical Analysis / Q000379:methods; D001786:Blood Glucose / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D005215:Fasting; D015309:Glucose Clamp Technique; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology*; D008297:Male; D015203:Reproducibility of Results
D001786:Blood Glucose; D007328:Insulin