The short insulin tolerance test lacks validity in adolescents with Type 1 diabetes.

AIMS: 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.