Continuous Subcutaneous Insulin Infusions: Closing the Loop

Abstract

Context: Continuous subcutaneous insulin infusions (CSIIs) and continuous glucose monitors (CGMs) have revolutionized the management of diabetes mellitus (DM). Over the last 2 decades the development of advanced, small, and user-friendly technology has progressed substantially, essentially closing the loop in the fasting and postabsorptive state, nearing the promise of an artificial pancreas (AP). The momentum was mostly driven by the diabetes community itself, to improve its health and quality of life.

Evidence acquisition: Literature regarding CSII and CGM was reviewed.

Evidence synthesis: Management of DM aims to regulate blood glucose to prevent long-term microvascular and macrovascular complications. CSIIs combined with CGMs provide an integrated system to maintain tight glycemic control in a safe and uninterrupted fashion, while minimizing hypoglycemic events. Recent advances have allowed to "closing of the loop" by better mimicking endogenous insulin secretion and glucose level regulation. Evidence supports sustained improvement in glycemic control with reduced episodes of hypoglycemia using these systems, while improving quality of life. Ongoing work in delivery algorithms with or without counterregulatory hormones will allow for further layers of regulation of the AP.

Conclusion: Ongoing efforts to develop an AP have created effective tools to improve the management of DM. CSIIs and CGMs are useful in diverse populations ranging from children to older individuals, as well as in various clinical contexts. Individually and more so together, these have had a tremendous effect on the management of DM, while avoiding treatment fatigue. However, cost and accessibility are still a hindrance to its wider application.

Keywords: DIY; artificial pancreas; continuous glucose monitor; continuous subcutaneous insulin infusion; diabetes mellitus; hypoglycemia; insulin pumps.