Insulin resistance and iatrogenic hyperinsulinemia in type 1 diabetes - norm or complication? Role of metformin in type 1 diabetes mellitus

There is a rising trend of overweight and obesity among individuals with type 1 diabetes. This is often associated with decreased insulin sensitivity, increased insulin dose requirements and poor glycemic control. Insulin resistance is a state of diminished effect of insulin on target tissues, despite normal or elevated serum insulin levels. Metformin as an adjunct to insulin in treating overweight or also not specific image of insulin resistance (without overweight or hormonal disorders) adults with type 1 diabetes is increasingly used. The main goal of this off-label type 1 diabetes treatment method is to improve insulin signaling leading to a subsequent increase in glucose uptake by skeletal myocytes, inhibition of hepatic gluconeogenesis and, as a result, a reduction in the need for a daily dose of insulin. The use of metformin as an addition to insulin may increase the chance of achieving target glucose control and reduce the anabolic effect of this hormone. Metformin can improve insulin sensitivity, glycemia and modulate cardiovascular disease risk factors or nonalcoholic fatty liver disease. In the vast majority of clinical trials conducted with metformin in type 1 diabetes, the effect of the drug on daily insulin doses, improvement in lipid parameters, and decline in body fat was assessed without correlating pre-specified outcomes with drug plasma concentrations.