Clinical Experience With U-500 Regular Insulin in Obese, Markedly Insulin-Resistant Type 2 Diabetic Patients

Abstract

On a clinical basis, severe insulin resistance is defined as a situation in which a patient requires >200 units of insulin daily for >2 days (1). This definition was determined >50 years ago, when it was erroneously believed that the human pancreas secreted ∼200 units of insulin a day. Although it is now known that the normal pancreas secretes only 20–40 units of insulin a day, this clinical definition is helpful because it delineates a very small group of patients, many with a number of unusual underlying problems. In adults, the conditions associated with clinical insulin resistance are gross obesity, severe infection, Cushing’s syndrome, acromegaly, hemochromatosis, lipodystrophic diabetes, genetic insulin receptor abnormalities, insulin receptor antibodies, Werner’s syndrome (adult form of progeria), insulin degradation at the injection site, and high titers of IgG insulin binding antibodies (immune mediated). Gross obesity is by far the most common condition. Although a recent review (2) discussed the use of U-500 regular insulin in states of severe insulin resistance, no detailed description of how to start and adjust doses of this concentrated form of insulin was given. This article provides a treatment algorithm for the use of U-500 regular insulin and summarizes our experience with obese, markedly insulin-resistant type 2 diabetic patients. …