Dynamics of intravenous glucose tolerance test parameters in obese adolescents after metformin therapy

In our country, the real prevalence of early stages of carbohydrate metabolism disorders across all age groups was studied not enough. We conducted an open observational study that comprised 58 adolescents (28 females and 30 males) with obesity of 1-4 th degrees. The evaluation of early carbohydrate metabolism disorders in adolescents was based on the results of oral (OGTT) and intravenous glucose tolerance (IVGTT) tests; dynamic changes in parameters were estimated in the presence of metformin therapy. Early markers of carbohydrate metabolism disorders were high level of glycemia at the third minute of IVGTT, slow decline in blood glucose, and high postprandial level of glycemia. Six-month metformin therapy in obese adolescents with impaired glucose tolerance resulted in an increase in the index of insulin resistance HOMA due to a decrease in the level of glycemia and an increase in the fasting insulin concentration suggesting recovery of the secretory function of ß-cells. Data of IVGTT compared with OGTT enabled to differentiate carbohydrate metabolism disorders at early stages, to identify a primary mechanism (reduction of insulin secretion or impaired peripheral glucose utilization rate), and to assign patients with obesity to groups of high risk for type II diabetes mellitus. Further studies are required for more careful identification of optimal dose and duration of metformin therapy.