The effect of short-term continuous intravenous insulin infusion on long-term metabolic control in patients with type 2 diabetes

Abstract

Background and aims. In a large group of obese patients with type 2 diabetes achieving good metabolic control is extremely difficult, despite using all treatment options available in the outpatient setting (i.e. intensive education, intensive high-dose insulin treatment combined with oral antidiabetic agents administration). These patients may be treated with continuous intravenous insulin infusion (CIVII) in hospital as this mode of treatment improves blood glucose level rapidly and is believed to counteract glucose toxicity. However, the long-term effect of this procedure on metabolic control in diabetes is unknown. We conducted the study to assess the effect of short term CIVII on long term glucose control in obese subjects with type 2 diabetes. Material and methods. The experimental group comprised of 36 type 2 diabetes patients treated with insulin [23 women and 13 men, mean age (± SD) 59.9 ± ± 7.7 years, diabetes duration 6.3 ± 3.0 years, body weight 92.9 ± 19.1 kg, BMI 33.5 ± 5.8 kg/m 2 , HbA 1 c 9.7 ± 1.8%]. In all subjects body weight, BMI, waist-to-hip ratio (WHR), blood pressure, fasting plasma triglycerides, total cholesterol, LDL and HDL cholesterol, and HbA1c levels were measured before and 6 months after CIVII. CIVII was applied for at least 72 hours; it consisted of basal insulin infusion and three 90-min insulin boluses per day administered at the meal time. Capillary blood glucose level was measured every 90–120 min throughout the day and night. During the study period the subjects who used oral antidiabetic medication maintained it at stable doses. In the control group of 24 type 2 diabetes patients (mean age 61.3 ± 7.2 years, BMI 32.8 ± 5.1 kg/m 2 , HbA 1c 9.4 ± 1.6%), who were subjects of a standard outpatient care, the same parameters as in the experimental group were examined at baseline and after 6-months. Results. In obese type 2 patients 6 months after CIVII treatment HbA 1c decreased significantly to 8.8 ± 1.6% (p < 0.05); however, no improvement in body weight, WHR, blood pressure or plasma lipid parameters was noted. Shortly after CIVII, daily insulin dose was significantly reduced (from 64.5 ± 24.6 at baseline to 50.7 ± 10.8 IU/day on discharge from the hospital, p < 0.05); yet 6 months later it was similar to the baseline insulin requirement. In the control group no statistically significant changes in analysed parameters were found during the study period. Conclusion. In patients with type 2 diabetes with poor metabolic control CIVII results in significant improvement of long-term glucose control, with no effect on other metabolic parameters.