Continuous glucose monitoring may improve glycaemic control

CGM monitor

This systematic review of randomised trials found nine studies that investigated whether continuous glucose monitoring (CGM) compared with self-monitoring of blood glucose (SMBG) led to improved glycaemic control or a reduction in hypoglycaemic episodes.

The reviewers combined the results of the study in a meta-analysis to measure the benefit of CGM compared with conventional treatment with SMBG.

Bottom line

Continuous glucose monitoring may improve glycaemic control amongst adult diabetics with poor control.  The meta-analysis for type 1 diabetes saw an average reduction in Hba1c of 0.5% (95% confidence interval 0.69% to 0.30%) whilst type 2 diabetes saw an average reduction of 0.70% (95% confidence interval 1.14% to 0.27%).

About the review

  • Patients:  Diabetes (type 1 and type 2), most with HbA1c >8%.
  • Intervention: Continuous glucose monitoring (CGM) compared with Self-Monitoring of Blood Glucose, with at least 8 weeks follow-up
  • Outcomes:  Glycaemic control (HbA1c) and hypoglycemia

Appraisal tips

Readers of this review are advised to consider the following:

  • The individual studies were reported as low to moderate quality.  These were small studies and therefore more likely to be subject to bias.
  • It seems likely that important differences between individual studies (such patient characteristics, how the interventions were delivered and the duration of follow-up) might undermine the validity of combining them into a single overall measure of beneit.


The studies varied in the duration and frequency of CGM and SMBG.


Efficacy of continuous glucose monitoring in improving glycemic control and reducing hypoglycemia: a systematic review and meta-analysis of randomized trials.


J Diabetes Sci Technol. 2011;5(4):952-65


Authors: Gandhi GY, Kovalaske M, Kudva Y, Walsh K, Elamin MB, Beers M, Coyle C, Goalen M, Murad MS, Erwin PJ, Corpus J, Montori VM, Murad MH

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I am an information scientist with an interest in making knowledge from systematic research more accessible to people who need it. This means you. I've been attempting this in the area of Evidence-Based Health Care since 1995. So far the results have been mixed. For some reason we expected busy clinicians to search databases and appraise papers instead of seeing patients. We also expected publishers to make the research freely available to the people who paid for it.. Ha! Hence The National Elf service.

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