Insulin-derived Amyloidosis and Poor Glycemic Control: A Case Series

Abstract Objectives Insulin- derived amyloidosisis a rare skin-related complication of insulintherapy. The purpose of this study was to show the effects of insulin- derived amyloidosison blood glucose levels, insulindose requirements, and insulinabsorption. Methods Seven patients were found to have insulin- derived amyloidosisat the Tokyo Medical University Ibaraki Medical Center. The clinical characteristics and insulintherapy of the 7 patients were investigated. Insulinabsorption was studied by comparing the serum insulinlevels after insulininjections into insulin- derived amyloidosissites versus injections into normal sites in 4 patients. Results When the insulin- derived amyloidosiswas discovered, the mean hemoglobin A1c level was 9.3%, and the mean daily insulindose was 57 units. After changing the injection sites to avoid the insulin- derived amyloidosis, the blood glucose concentrations improved, and the mean daily insulindose could be reduced to 27 units ( P = .035; 53% reduction). The insulinabsorption at insulin- derived amyloidosissites was 34% of that at normal sites ( P = .030). Conclusions Insulin- derived amyloidosiscaused poor glycemic control and increased insulindose requirements because of impairments in insulinabsorption.