Objective: To report our experience with use of U-500 regular insulin (U-500) for continuous subcutaneous insulin infusion (CSII) in four patients with type 2 diabetes requiring high-dose insulin.
Methods: We performed a retrospective review of medical records of four patients with type 2 diabetes and insulin resistance who were using U-500 in a CSII regimen for at least 6 months. Before treatment conversion, two patients were receiving CSII with use of insulin lispro, and two were receiving multiple daily insulin injections. Clinical assessment was monitored with glycosylated hemoglobin (HbA1c) levels. Changes in the insulin volume administered and associated cost savings are analyzed.
Results: Three months after conversion to U-500 therapy, the average HbA1c decreased from 10.8% to 7.6%. By 6 months, it declined further to 7.3%. With use of U-500, the absolute volume of insulin infused per day decreased by at least fourfold. This volume reduction led to potential cost savings for insulin of up to $2,600 per year per patient and a savings for pump supplies of up to $3,400 per year per patient. All patients had subjective improvement in quality of life.
Conclusion: We propose that smaller volumes of insulin with use of U-500 allow for more efficient absorption of large doses of insulin and yield improved glycemic control. In our four patients, the use of U-500 for CSII resulted in improved quality of life, cost savings for treatment, and potential reduction in diabetes-related complications based on the decline in HbA1c. This treatment method may be a novel alternative for patients with type 2 diabetes and insulin resistance who have not met goal glycemic control with standard intensive regimens or who require insulin doses exceeding current insulin pump delivery capacity.