No flash results from CGM study in T2D

Use of professional-mode flash glucose monitoring in adults with type 2 diabetes does not result in improved HbA1c or diabetes-related distress, Australian research has found.

However the study conducted across 25 general practices in Victoria found the intervention did improve the time spent in the target glucose range over 12 months.

The pragmatic, open label study included almost 300 patients randomised to either the flash glucose monitoring checked at three-monthly intervals for 12 months or usual care. 

Eligible patients had baseline HbA1c above target despite at least two non-insulin glucose lowering drugs, or insulin, or both.  

Those in the intervention group were requested to wear the sensor for 5-14 days ahead of their scheduled three-monthly GP visits at which GPs would upload and discuss the data. 

The study found while HbA1c did improve with the intervention at six months, by the end of the study the mean HbA1c improvement with flash glucose monitoring (8.9% to 8.2%) was no better than in the control group (8.9% to 8.5%). 

However the percentage time in target glucose range of 4-10 mmol/L was 54.8% with monitoring compared to 46.9% with usual care. They found the difference was most marked during the day than overnight

The study noted the proportion of participants wearing the sensor fell to 78% at nine months.

And there was evidence of therapeutic inertia.

“We identified little evidence of change in prescribing to intensify treatment with the flash glucose monitoring intervention,” the study said.

“We might have identified a larger effect of the intervention with greater practitioner adherence to the study protocol (including completion of the educational training by all GPs); however, our trial provides evidence of the likely effect in the context of current practice when access to this technology is made available together with a realistic and sustainable training resource.”

They noted their findings were unlikely to be specific to the Freestyle Libre monitoring system and more likely to be “generalisable to the range of professional-mode CGM devices available”.

An accompanying Comment article in The Lancet Diabetes & Endocrinology said reducing HbA1c in type 2 diabetes with flash glucose monitoring was not straightforward.

“Improving glycaemic control with intermittent use of flash glucose monitoring in people with type 2 diabetes seems to be more complex than just wearing a sensor.” 

The authors said further measures such as self-management education for users of flash glucose monitoring on the effects of behavioural factors and pharmacological interventions on glucose excursions might help increase efficacy.

As well, a more shared decision-making approach could be beneficial.

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