Influence of insulin treatment on insulin sensitivity in insulin requiring type 2 diabetes patients

Insulin resistance in type 2 diabetes subjects was investigated before and 6 months after insulin administration in 43 type 2 diabetes patients (28 females and 15 males). Their age was 56.1 ± 8.6 years, diabetes duration 11.7 ± 6.8 years, BMI 29.5 ± 5.3 kg/m2. All patients were on maximal dosage of oral hypoglycaemic agents and had poor metabolic control (HbA1c 11.2 ± 1.6%). Insulin sensitivity was measured by euglycaemic clamp (insulin infusion rate 1 mU kg−1 min−1). The glucose disposal rate (M-value) was considerably lower in patients (2.4 ± 1.6 mg kg−1 min−1, 0.2-8.1) compared with healthy subjects (7.1 ± 0.2 mg kg−1 min−1, p < 0.01). M-value was strongly associated with WHR (r = −0.41, p < 0.05). The patients with poorest insulin sensitivity had the highest level of total cholesterol (r = −0.41, p = 0.02) and LDL-cholesterol (r = −0.38, p = 0.03). After 6 months of insulin treatment BMI was 30.3 ± 4.2 kg/m2 (p < 0.05), mean weight increase was 2.7 ± 0.8 kg. M-value was substantially increased to 4.5 ± 2.3 mg kg−1 min−1 (p < 0.001), the degree of improvement depended on basal insulin sensitivity (r = −0.55, p < 0.01). HbA1c was reduced to 7.7 ± 1.4% (p < 0.01), the correlation M-value with change of HbA1c (r = −0.59, p < 0.01) was shown. Total cholesterol decreased from 6.3 ± 1.1 to 5.4 ± 1.1 mmol/l, LDL-cholesterol from 4.1 ± 1.1 to 3.4 ± 1.0 mmol/l, triglycerides from 2.6 ± 1.6 to 1.6 ± 0.7 mmol/l (p < 0.001). In conclusion, insulin treatment of type 2 diabetes patients leads to decrease in insulin resistance due to reduction in glucose toxicity and plasma atherogenicity despite weight gain.