Continuous Glucose Monitoring: A Perspective on Its Past, Present, and Future Applications for Diabetes Management

The transition from urinary glucose measurement to more sophisticated self-monitoring of blood glucose (SMBG) systems in the 1970s and 1980s dramatically changed the approach to and understanding of diabetes management (1). Innovations in the design and technology of portable blood glucose meters have become integral to the success of intensive treatment of both type 1 and type 2 diabetes, and the outcome of this treatment has led to a tremendous decrease in the development of long-term micro- and macrovascular complications (2–4). However, intensive insulin therapy has its limitations, including increased frequency of hypoglycemia and the need for frequent SMBG testing. In the past decade, continuous glucose monitoring (CGM) technology has evolved into a novel tool to support diabetes management. Unlike conventional glucose meters, which provide a snapshot of the blood glucose value at the time of testing, CGM provides semi-continuous information about glucose levels. It does this indirectly, by extrapolating blood glucose levels from interstitial fluid glucose via an algorithm. Importantly, CGM allows users to make decisions regarding their day-to-day diabetes management using real-time glucose trends. Along with this information, CGM systems provide customizable hypo- and hyperglycemia alarms and display trends of the rate of change of glucose levels. Most recently, CGM systems have been integrated with insulin pumps and are being used in artificial pancreas clinical trials. In this article, we discuss the clinical benefits of CGM; its challenges, including accuracy and user experience; and its present and future role in the management of diabetes. Numerous studies have explored whether sustained use of CGM offers clinical benefits in individuals with diabetes. Randomized, multicenter clinical trials have shown improved glycemic control in adults with type 1 diabetes using CGM compared to those using SMBG and a reduction in the time spent in hypoglycemia with concomitant improvement in A1C …