[Insulin sensitivity measured with euglycaemic clamp technique in newly diagnosed diabetes mellitus]

The purpose of the study was to identify insulin resistance (IR) at the onset of diabetes mellitus type 2 and type 1 using euglycaemic clamp technique. The study was conducted in 51 subjects: 30 patients with newly diagnosed diabetes, 9 with type 1, mean age 29.3 +/- 6.6 yrs (SD), 21 with type 2, mean age 47.8 +/- 10.7 yrs and 21 control healthy subjects (mean age 43.5 +/- 13.9 yrs). In last group there was an increase in IR proportional to patients age (r = 0.78, p < 0.01). IR was more pronounced in obese subjects in comparison to non-obese subjects, index of tissue glucose disposal M was respectively 3.4 +/- 2.2 and 6.6 +/- 1.7 mg/kg x min, p < 0.005. M value was decreased also in patients with abdominal obesity measured with WHR, r = 0.73, p < 0.0005. The normal range for this method was 3.3 to 10 mg/kg x min. Insulin sensitivity is decreased in both types of newly diagnosed diabetes, in type 1 to 2.3 +/- 0.5 and in type 2 to 1.7 +/- 0.8 mg/kg x min as compared with control group. In diabetes type 1 IR was correlated with degree of hyperglycaemia measured with HbA1c ("glucotoxicity"). The lowest M values was found in diabetes type 2 with obesity. There were no significant abnormalities in insulin secretion in diabetic groups. These results suggest that the primary disturbance at the onset of diabetes mellitus is IR.