- Continuous glucose monitoring (CGM) is a way to monitor blood glucose levels throughout the day via a small device worn just under the skin that measures the amount of glucose in the blood.
- Self-monitoring of blood glucose levels isn't common in people with type 2 diabetes but we know that monitoring blood sugar levels is a useful way to manage the condition.
- Researchers are exploring how CGM can be used to support the habits behind the weight loss and associated dietary changes that are effective type 2 diabetes management techniques.
With 1 in 10 in the UK living with type 2 diabetes, making up 90% of all diabetes diagnoses, there’s no hiding from the fact that it's an urgent health priority. Research now shows that substantial weight loss and dietary adjustments can help patients reach remission.[2,3] With diabetes costing the NHS £10 billion a year, managing the condition via behaviour change is a growing area of interest for both clinicians, patients, and of course, us here at Habitual.
People with diabetes are unable to maintain steady blood sugar levels. Behavioural risk factors such as being overweight, eating a poor diet, drinking lots of alcohol, or having high stress levels, are behind this lack of control. Diagnosis and management of diabetes tends to rely on HbA1c measurements, but what if we could find a way to understand the impact of different behavioural decisions on blood glucose levels?
What is continuous glucose monitoring?
A CGM is a device that continuously measures the body’s glucose levels, day and night. The small device worn just under the skin measures the amount of glucose in the fluid that surrounds the body’s cells, called the interstitial fluid. This information is then sent to a display device, such as a mobile phone. The data can be accessed immediately by the user and even shared with healthcare teams, a factor that has been crucial for virtual diabetes care during the COVID-19 pandemic. There are two types of CGM available - real-time, when you can check levels at any time and download them, and retrospective, when levels can’t be viewed in real time but past levels can be downloaded and analysed. Everyone with type 1 diabetes needs to self-monitor their blood sugar levels to take insulin, making CGM more common in type 1 diabetes management than type 2.
CGM and type 2 diabetes
Self-monitoring of blood glucose levels isn’t common in people with type 2 diabetes, but we know how insightful it can be even when you’re not on insulin or other blood sugar lowering medications. Evidence for the use of CGM in people with type 2 diabetes lags well behind its use in type 1 diabetes, but there is growing interest in its potential to benefit all type 2 individuals, not just people taking insulin. One study showed that CGM helped patients spend more time with their blood glucose in target range. This improved control was seen in both type 1 and type 2 diabetes and similar findings are building the case for using CGM in type 2 diabetes care.
Many of the trials investigating CGM are focusing on type 1 and type 2 using insulin therapy to manage their diabetes. But what about people with type 2 diabetes who don’t use insulin?
Behaviour change and CGM
Cultivating new, healthy habits is a promising behaviour change approach to not only losing weight, but also maintaining it. This weight loss and associated dietary changes are effective type 2 diabetes management techniques, and they even have the potential to put it into remission. Researchers are now wondering whether CGM could create behaviour change opportunities. Everyone responds differently to food and exercise, and CGM can capture these unique responses to answer why blood glucose is out of control in an individual.
Studies on CGM in type 2 (using and not using insulin) individuals are few and far between, but we are starting to see some promising results. A review of existing studies found that using CGM reduced HbA1c levels, helped with weight loss, encouraged users to stick to a healthy eating plan, and increased physical activity. Patients using CGM have been found to make healthier choices and in another study, 90% of CGM users felt that its use contributed to a healthier lifestyle.
How does CGM lead to behavioural change?
We can speculate that accessing CGM data keeps motivation high and empowers users to feel like they are in control of their diabetes management. This is a powerful feeling and no doubt contributes to making healthier choices.
For people with type 2 diabetes, gaining insight into their body’s response to a certain food or physical activity can be one of the most effective ways to understand and manage the condition. CGM would allow people to learn about their body and how different foods or sports affect blood sugar levels. This information could then be used to create a diet that suits their body and avoids the often serious swings in blood sugar after an activity.
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The challenges of CGM
As interest in this idea grows, there are a few challenges to think about. CGMs are expensive devices to purchase personally and availability on the NHS is very limited, making them currently quite inaccessible. Data interpretation is also going to be key in the success of delivering behaviour change through CGM. The amount of data generated could be overwhelming and confusing, making it ineffective. Users will need to be educated on how to understand and act on the data. Having the data explained in the context of a user’s personal experience of health might also go a long way to maintaining motivation and healthy habits. It would also be beneficial for users to understand why their health teams are advising them to eat in a certain way, move more and take medication.[12,13] This all contributes to that feeling of empowerment - people with diabetes deserve to be in control of their condition.
The future is personal
Despite these challenges, wider use of CGM is an exciting prospect. For those in diabetes care, it will be interesting to see how people use the data for behaviour change and whether it works.
CGM also has the potential to be a key player in personalised medicine and this will be really exciting to follow. The data gathered by CGM could help healthcare teams provide tailored, individualised advice to people with diabetes. Imagine that? Dietary advice specific to your unique response to food, an exercise plan that works with your blood sugar level fluctuations during activity, and medicine prescribed for a reason rather than as course. Sounds pretty incredible doesn’t it?
 Number of people with diabetes reaches 4.7 million. Diabetes UK. Retrieved 1 September 2021. Accessible here.
 Taheri, S., Zaghloul, H., Chagoury, O., et al. (2020). Effect of intensive lifestyle intervention on bodyweight and glycaemia in early type 2 diabetes (DIADEM-I): an open-label, parallel-group, randomised control trial. Lancet Diabetes Endocrinol 8(6):P477-489. Accessible here.
 Lean, M.E.J., Leslie, W.S., Barnes, A.C., et al. (2018). Primary care-led weight management for remission of type 2 diabetes (DiRECT): an open-label, cluster-randomised trial. Lancet 391(10120):P541-551. Accessible here.
 The cost of diabetes report. Diabetes UK. Retrieved 1 September 2021. Accessible here.
 American Diabetes Association. (2018). Good to Know: Factors Affecting Blood Glucose. Clin Diabetes 36(2):202. Accessible here.
 Maiorino, M.I., Signoriello, S., Maio, A., et al. (2020). Effects of Continuous Glucose Monitoring on Metrics of Glycemic Control in Diabetes: A Systematic Review With Meta-analysis of Randomized Controlled Trials. Diabetes Care 43(5):1146-1156. Accessible here.
 Beck, R.W., Riddlesworth, T.D., Ruedy, K., et al. (2017). Continuous Glucose Monitoring Versus Usual Care in Patients With Type 2 Diabetes Receiving Multiple Daily Insulin Injections: A Randomized Trial. Ann Intern Med 167(6):365-374. Accessible here.
 Taylor, P.J., Thompson, C.H., Brinkworth, G.D. (2018). Effectiveness and acceptability of continuous glucose monitoring for type 2 diabetes management: A narrative review. J Diabetes Investig 9(4):713-725. Accessible here.
 Ehrhardt, N., Al Zaghal, E. (2020). Continuous Glucose Monitoring As a Behavior Modification Tool. Clin Diabetes 38(2):126-131. Accessible here.
 Daly, A., Hovorka, R. (2021). Technology in the management of type 2 diabetes: Present status and future prospects. Diabetes Obes Metab 23(8):1722-1732. Accessible here.
 Continuous Glucose Monitoring (CGM). Diabetes UK. Retrieved 1 September 2021. Accessible here.
 Graffigna, G., Barello, S., Libreri, C., Bosio, C.A. (2014). How to engage type-2 diabetic patients in their own health management: implications for clinical practice. BMC Public Health 14, 648. Accessible here.
 Caruso., R., Magon, A., Baroni, I., et al. (2018). Health literacy in type 2 diabetes patients: a systematic review of systematic reviews. Acta Diabetol 55(1):1-12. Accessible here.