Real-Time Continuous Glucose Monitoring for People Living With Diabetes


For people living with diabetes, blood glucose monitoring is used in combination with insulin therapy to adjust insulin doses and maintain glucose control. The traditional method is self-monitoring of blood glucose (SMBG) using a glucometer. However, SMBG requires a fingerstick to take a blood sample, which can be painful and time-consuming. Some people find it difficult to practice SMBG at the recommended rates. Additionally, nocturnal or asymptomatic hypoglycemia (low blood glucose) may not be recognized through SMBG, and severe hypoglycemia can lead to coma or death. 

Another option is continuous glucose monitoring (CGM), which is a method of glucose testing in which a sensor is inserted into the skin and continuously monitors interstitial glucose concentrations. Real-time continuous glucose monitoring (rtCGM) systems have the capability for alerts and alarms for current and/or impending glycemic events such as hyperglycemia (high blood glucose) or hypoglycemia. In comparison,  i intermittently scanned continuous glucose monitoring (isCGM) systems, as known as flash glucose monitoring (FGM) systems, measure glucose levels every minute and store 1 value every 15 minutes. However, they require the person using the information to scan the sensor to display information (i.e., it is not done automatically), and only the most recent 8 hours of data are retained. 

CADTH undertook 4 rtCGM-related reports in 2022:

  • the first compared rtCGM to isCGM (FGM) for people living with type 1 diabetes, type 2 diabetes, or gestational diabetes 
  • the second compared rtCGM to SMGB for people living with type 1 diabetes
  • the third compared rtCGM to SMBG for people living with type 2 diabetes
  • the fourth searched for evidence-based guidelines regarding the use of rtCGM for people living with type 1 diabetes or type 2 diabetes.

The details and findings of these 4 reports are summarized here, followed by summaries of additional CADTH work on CGM more broadly (including both rtCGM and isCGM [FGM] systems).