In a study that looked at people who had long standing type 1 diabetes (average duration of 31 years) they found that the use of CGM was a major benefit.
Following glucose levels with a CGM helped individuals improve awareness of their own glucose levels as well as make lifestyle changes to avoid low BG.
The reason for hypoglycemia unawareness in many with long standing diabetes is related both to the absence of counter-regulatory response by the body as well as lack of awareness of symptoms that the person can acknowledge. Usually symptoms of low BG such as shakiness, sweating, rapid heartbeat, irritability, weakness and hunger tell the person that BG may be dropping or already low. With longstanding diabetes, these symptoms may change or not be present at all due to changes in the sympathetic nervous system response. This leaves people with diabetes at a loss for treating the drop in BG before it gets too low, especially when sleeping.
Addition of a CGM with alerts for low BG as well as High BG can help ease the burden of management and prevent severe hypoglycemia. The important factor being proper education in use of the system to ensure the person with diabetes is responding to alerts as well as making lifestyle changes to avoid the drops in BG. This is best done with a team approach to management.