Continuous glucose monitoring may offer improved glycaemic control in type 1 diabetes

By Jane Lewis
Two studies published in the Journal of the American Medical Association report that use of continuous glucose monitoring (CGM) resulted in improved glycaemic control in patients with type 1 diabetes who inject insulin multiple times daily, compared with the use of self-monitored blood glucose (SMBG). 

Speaking to Medicine Today, Professor Stephen Twigg, Head of the Department of Endocrinology at Royal Prince Alfred Hospital, Sydney, and Stan Clark Chair in Diabetes at The University of Sydney, said that CGM systems are not only enabling more frequent monitoring of glucose to become a reality, they are also progressively becoming more user-friendly, accurate and precise. 

‘The great strength of CGM systems in clinical care is that they show real-time, current trend patterns in glucose levels, enabling the person with diabetes to take prompt preventive or treatment action to help keep the glucose in the desirable target range,’ he said. 

In the first of the two studies, the DIAMOND trial, US researchers randomised 158 patients with type 1 diabetes with baseline glycated haemoglobin (HbA1c ) levels of 7.5% to 9.9% (58 mmol/mol to 85 mmol/mol) to receive CGM or perform SMBG. Results at 24 weeks showed a significantly greater decrease in HbA1c level with CGM vs SMBG (-1.0% vs -0.4%; p< 0.001). 

In the second study, the GOLD trial – a crossover study conducted in Sweden involving 161 patients with type 1 diabetes and HbA1c of at least 7.5% (58 mmol/mol) – participants used CGM and SMBG for 26 weeks each, with a 17-week washout period in between. Mean HbA1c was significantly lower during CGM use compared with SMBG (7.92% [63 mmol/mol] vs 8.35% [68 mmol/mol]; p< 0.001). 

Professor Twigg noted that recent research, including the GOLD and DIAMOND trials, has shown that the frequency of hypoglycaemia and hyperglycaemia, as well as average HbA1c and glucose variability, are all improved by the use of CGM in patients with type 1 diabetes. 

‘In future years, it is envisaged that CGM systems will be an integral part in the complete “closed loop” artificial pancreas treating type 1 diabetes,’ he commented. ‘In time, people with type 2 diabetes may also be found to benefit from using regular CGM.’ 

The author of an accompanying editorial said that while both the JAMA studies ‘clearly show a benefit of CGM compared with SMBG for patients with type 1 diabetes,’ there are ‘several caveats regarding the findings’ including the cost and invasiveness of CGM. Further clinical trials are needed to determine the long-term effects of CGM, as well as its potential utility in patients with type 2 diabetes, they wrote.
JAMA 2017; 317: 371-378.
JAMA 2017; 317: 379-387.