Click to Join #WeDeserveBetter, the type 1 diabetes community (people with T1D, carers, HCPs, CGM industry) wanting a change in CGM regulation. (If you came for the Glucose Never Lies education content, click here)

A change to ensure we understand the risk of using ALL the available CGM devices, so we are not left in the dark using CGM devices with unknown risks!

No CGM device is risk-free, but some have much less risk than others.

We do not understand the risk of some CGM devices due to regulations allowing approvals based on small samples of confidential data or data from a device that is deemed to be similar.

#WeDeserveBetter as a type 1 community.

We deserve to understand the risk and decide what we use accordingly.

Click to Join #WeDeserveBetter, and support the meeting with MHRA (UK national patient safety regulator) in March 2023.

Read below (4 minutes) to learn more or watch this video for a detailed explanation (25 mins)

Understanding CGM risk


I am a Paediatric Diabetes Dietitian living with type 1 diabetes, leading the CGM service at the Birmingham Children’s Hospital, supporting over 300 children with type 1 diabetes. I am concerned that some CGM devices available for people living with type 1 diabetes in the UK and Europe do not have sufficient accuracy and safety data publicly available.

This is despite them having CE marking, which confirms that they meet the “Essential requirements” of the European Commission. CGM devices can be sold in the UK and many European places if they have CE marking. Therefore, CE marking is unwittingly considered a reliable marker of CGM device accuracy and safety for health care professionals, funders, and people living with type 1 diabetes.

My concern has escalated since the National Institute for Clinical Excellence (NICE) updated its guidance for CGM in March 2022, recommending that everyone living with type 1 diabetes access either CGM or Flash on the NHS. This makes the UK market attractive to manufacturers offering CGM devices with varying accuracy and functionality.

The NICE guidance states that the accuracy of the CGM device should be the first consideration. However, it does not guide assessing CGM accuracy, and CE marking is thought reliable. Once deemed accurate and comparable, the NICE guidance recommends selecting the cheapest CGM device. Therefore, understanding if CE marking is reliable for accuracy and safety for adults and children with type 1 diabetes is essential.


I contacted leading researchers in the UK and Europe for their help. We decided to review the CE marking system and compare it to the approvals process used by regulatory bodies in the USA (the Food and Drug Administration (FDA) and Australia (the Therapeutic Goods Administration (TGA).

The manufacturers of CGM devices trading in the UK provided the clinical data supporting their CE marking for type 1 diabetes. We reviewed this data against the FDA’s tighter iCGM approvals process for CGMs, which are the most robust measures currently available. 


The USA FDA and Australian TGA approval are reliable markers that CGM devices have clinical data on adults and children with Type 1 Diabetes. They use more robust assessment criteria that require clinical data on each device, adults, and children. Therefore we have a reasonable idea of the risk of using CGM devices with FDA and TGA approval.

In contrast, CE marking is not a reliable marker for the accuracy and performance of CGM devices. There are no standardised criteria, and when deciding on which type of diabetes and the age range of people the device should be approved for, the CE marking agencies accept a small sample of clinical data and data from a similar device with no criteria on how to assess similarity or representativeness. 

This has led to the GlucoMen Day®, GlucoRx Aidex™, and Medtrum TouchCare® Nano being approved for children with type 1 diabetes despite having no publicly available clinical data on that age group. Also, the GlucoRx Aidex™ is available for adults with type 1 diabetes based on a study where more than 80% of participants had type 2 diabetes.

Consequently, we do not understand the risk of using these devices for the populations where data is missing. These devices may be the lowest risk ones or the highest risk ones, the point is we do not know at present. More importantly, without the help of national patient safety regulators (e.g. MHRA), we cannot determine the risk. The type 1 diabetes community deserves better than that, in my opinion.

Assessment of CGM device clinical data against the FDA’s iCGM Criteria showed that only the following devices meet selected point accuracy standards for adults and children with type 1 diabetes.

Dexcom ONE™, Dexcom G6™ and Dexcom G7™

FreeStyle Libre® 2 and FreeStyle Libre® 3


Let me be clear. I have no vendetta against any CGM device or company. Manufacturers play within the CE marking rules, and business is about survival. They are doing nothing illegal. If there is an efficient way to market, you have to take it. I firmly believe all Manufacturers are sure they have an excellent product where the risk is low for all people with type 1 diabetes, and they may be right. The critical point is:



For this, we need to see the data and have transparency in the approval process. Therefore;

Step 1: I am presenting this issue at the ATTD in Berlin on Saturday, the 25th of Feb, at 09.30. I want to raise awareness of this issue and network with influential people and organisations to foster transparency and change. 

Step 2: Present this information to the UK national regulator in March/April, the Medicines and Healthcare products Regulatory Agency (MHRA). The MHRA can ask manufacturers for the Declaration of Conformity and associated clinical data used to obtain CE marking recommendations. They can take action as needed and help us determine the risk.

Removal of unsupported approval for specific populations would prevent healthcare professionals and funders from selecting one of the above devices based on cost. More importantly, the unknown risk can be removed if manufacturers cannot provide the missing data. Furthermore, the UK taking such steps may provide the impetus for European member states to ask the same questions of their national regulators.

Step 3: Support the implementation of CGM study design and performance criteria for CE marking and UKCA marking (From July 2024). The IFCC working group on CGM is working on this criteria to make it an ISO standard. The IFCC team will need the push of the type 1 diabetes community to convert the criteria into regulation. This is where the type 1 diabetes community comes in! 


Click to join #WeDeserveBetter, and support the meeting with MHRA (UK national patient safety regulator) in March 2023. I will inform you how the type 1 diabetes community can help when the time is right.

I have no idea what that looks like right now. However, it will become apparent after the ATTD and MHRA meetings.

If you are compelled, please share #WeDeserveBetter with other people you think may be interested.

Copy me in if you are using Twitter @mm640g using #WeDeserveBetter


Read the CGM narrative review analysis published 30th December 2022.

Follow Tim Street @Tims_Pants and read and subscribe to his website – https://www.diabettech.com/

John Pemberton

T1D since 2008