This site is intended for healthcare professionals only
DiabetesontheNet Logo

Diabetes Digest


Early View

Share this article

Hypoglycaemia is less common with CGM than SMBG despite achieving the same HbA1c

Devices and Technology – September 2020 digest

CGM is associated with considerably less time in hypoglycaemia than SMBG at a broad range of HbA1c levels in people on multiple daily injections.

International Time in Range consensus guidelines recommend that continuous glucose monitoring (CGM) users aim to spend less than 4% of time with blood glucose levels under 3.9 mmol/L and less than 1% with levels under 3.0 mmol/L. However, these recommendations are largely based on studies of sensor-augmented insulin pump therapy, whereas most people with type 1 diabetes, including CGM users, use multiple daily insulin injections (MDI).

This study sought to compare time in hypoglycaemia and HbA1c levels between users of CGM and self-monitoring of blood glucose (SMBG) who were on MDI therapy. A total of 161 people were randomised to either CGM or SMBG for 6 months, followed by the other therapy for a further 6 months, with a 17-week washout period in between. Masked CGM was used in two of the last four weeks of the SMBG treatment phase to compare glucose metrics. Follow-up data were available for 137 participants.

Overall, the lower the HbA1c achieved, the more time was spent in hypoglycaemia in both CGM and SMBG users. Generally, these participants on MDI therapy found it harder to achieve both HbA1c and hypoglycaemia targets than insulin pump users in previous studies.

At all HbA1c levels, CGM users spent less time in hypoglycaemia than SMBG users. For instance, to achieve an HbA1c of <53 mmol/mol (7.0%), CGM users spent 5.4% of time with glucose levels under 3.9 mmol/L, compared with 9.2% of the time for SMBG users, and the two groups spent 1.5% versus 3.5% of time in grade 2 hypoglycaemia (<3.0 mmol/L). Similar patterns were observed when using Time In Range and mean blood glucose levels as the measure of glycaemic control.

The authors conclude that achieving both HbA1c and Time Below Range targets is challenging for people with type 1 diabetes treated with MDI, both with CGM and SMBG. However, CGM is associated with considerably less time in hypoglycaemia than SMBG at a broad range of HbA1c levels. They argue that CGM is crucial for individuals on MDI treatment if they are to achieve HbA1c targets and simultaneously avoid hypoglycaemia.

Seyed Ahmadi S, Westman K, Pivodic A et al (2020) The association between HbA1c and time in hypoglycemia during CGM and self-monitoring of blood glucose in people with type 1 diabetes and multiple daily insulin injections: a randomized clinical trial (GOLD-4). Diabetes Care 8 Jul [epub ahead of print].

Other Digests:

Related content
Free for all UK & Ireland healthcare professionals

Sign up to all DiabetesontheNet journals


By clicking ‘Subscribe’, you are agreeing that are able to email you periodic newsletters. You may unsubscribe from these at any time. Your info is safe with us and we will never sell or trade your details. For information please review our Privacy Policy.

DiabetesontheNet Logo

Are you a healthcare professional? This website is for healthcare professionals only. To continue, please confirm that you are a healthcare professional below.

We use cookies responsibly to ensure that we give you the best experience on our website. If you continue without changing your browser settings, we’ll assume that you are happy to receive all cookies on this website. Read about how we use cookies.