CLINICAL QUESTION

Does continuous glucose monitoring (CGM) offer a benefit over traditional glucose self-monitoring in patients with type 2 diabetes mellitus?

BOTTOM LINE

In relatively short-term studies, glucose monitoring devices have only a small effect on A1C levels and do not affect body composition, lipids, or blood pressure. Real-time (continuous) glucose monitors, such as Dexcom G6 and G5, Medtrum TouchCare Nano, and Medtronic Guardian models, may cause psychological stress in users. Intermittent glucose monitors, such as FreeStyle Libre, are better accepted by patients. Both types of devices increase the risk of adverse effects. (Level of Evidence = 1a)

SYNOPSIS

The researchers searched four databases, including Cochrane CENTRAL, and reference lists of retrieved articles to find randomized studies in any language of CGM and intermittently scanned CGM devices, identifying 26 studies of 2,783 patients. Following PRISMA guidelines, two authors selected articles for inclusion and one author abstracted the data, which were checked by another author. Most studies were relatively short (8 to 12 weeks). CGM had a small effect on reducing A1C levels (0.19% [percent, not percentage points] lower) but had no effect over the short term on body composition, blood pressure, or lipid levels. However, in the three studies that evaluated it, user satisfaction was lower with use of the device and adverse effects were higher (relative risk = 1.22; 95% CI, 1.01 to 1.47). On average, intermittently scanned CGM devices decreased A1C levels by 0.31% but also had no effect on body composition, blood pressure, or lipid levels. User satisfaction was improved with these devices, but adverse events were more likely (relative risk = 1.30; 95% CI, 1.05 to 1.62).