What is a flash glucose monitor?

In 2017, the FreeStyle Libre flash glucose monitor became available on prescription (subject to local health authority approval) in the UK, a landmark moment in the history of diabetes care. By the end of June 2020, 31% of people with type 1 diabetes in England had been prescribed flash glucose monitoring on the NHS.

"A flash glucose monitor records blood sugar levels continuously: you can view these by scanning its sensor with a reader or a smartphone app," says Dan Howarth, head of care at Diabetes UK.

"It shows you what your blood sugar level is, what direction it is travelling in and what it has been for at least the last eight hours. A newer version of this technology also alerts people to high and low blood sugar levels via an alarm."

All of the information the flash glucose monitor collects can be shared with a patient's healthcare professionals and reviewed during virtual appointments. This has been particularly helpful during the pandemic, with many people with diabetes saying it has improved their remote consultations.

"Flash glucose monitoring is suitable for both those with type 1 och typ 2 diabetes," says Dr Emma Wilmot, a consultant diabetologist with a specialist interest in type 1 diabetes and diabetes technology.

"NICE has just put its latest guidance out for consultation and it recommends flash glucose monitoring for all with type 1 diabetes and selected groups with insulin treated type 2 diabetes."

However, flash glucose monitoring access on the NHS tends to be restricted to people with type 1 diabetes in the UK, Howarth adds. To be eligible, people must meet specific criteria.

"We hope to see these criteria widened to ensure all people with type 1 diabetes and people with other types of diabetes who use insulin intensively (four or more injections a day) are able to access flash glucose monitoring should they want to," he says.

The device provides insight into a user's glucose levels 24/7, allowing people with diabetes to learn lots about the impact of their therapy and behaviour on their glucose. This leads to better outcomes and reduces the risk of diabetes complications, such as eye and foot problems, heart attacks och strokes.

In addition, the ability to share data with the user's healthcare provider allows the user to illustrate trends and patterns in blood glucose. This helps the patient and healthcare professional between them to create a fuller picture of the factors that may need to be addressed and how treatment should be adjusted.

There is a constant balance to be struck between avoiding high blood glucose, which can lead to serious long-term complications, and increasing the risk of debilitating and potentially dangerous hypoglycaemia (low glucose levels). Where trends and measurements are concerned, knowledge is power.

Research has shown flash glucose monitoring has demonstrated reductions in hypoglycaemia. It has also reduced hospital admissions in both those with type 1 and those with insulin-treated typ 2 diabetes.

"For example, if I asked you to drive from your home to a specific point in an unfamiliar city 100 miles away you would probably want to see your sat nav for the duration of the journey. This is what flash allows - constant monitoring and feedback on progress," says Wilmot.

"The alternative is finger-prick blood glucose monitoring a few times a day, which is the equivalent of only being allowed to look at your sat nav two to four times during the journey. In this scenario, the chances of taking a wrong turn are high," she adds.

Limitations of finger-prick testing

Finger-prick testing only tells you what your blood sugar level is at the moment you test, whereas flash provides a much richer picture. "These data can help people understand what foods affect them differently or how tränings impacts their blood sugar levels," says Howarth.

"It allows people to be proactive, rather than reactive. For example, if your blood sugars appear high but the trend arrow is pointing down, you may decide not to administer a corrective insulin dose because you know your blood sugar is coming down."

"The negatives include the need to wear the sensor on the arm 24/7 for a 14-day period, although most get used to this quickly. A small number with sensitive skin may struggle with this," says Wilmot.

"The other downside is data overload and people can on occasion feel a bit overwhelmed. However, the vast majority of the people I met in my clinic describe it as 'life changing' technology which they would not be without."

Howarth adds that burnout is a risk for anyone living with diabetes, so people should be given appropriate support. "People with diabetes should be supported to make best use of the technology they can most benefit from," he says.

"For some, this may mean additional support from healthcare professionals, as well as access to the relevant psychological support if they need it."