Real-time continuous glucose monitoring (CGM) can reduce the number of hypoglycaemic events in adults with type 1 diabetes and impaired hypoglycaemia awareness or severe hypoglycaemia, according to a German study.

The findings published in The Lancet support calls for adults with type 1 diabetes to have better access to CGM – currently only subsidised in Australia for under 21 year olds.

Diabetes Australia has previously called on the government to expand the funding for CGM to women planning a pregnancy or pregnant, and people with impaired hypoglycaemia awareness and/or severe hypoglycaemia.

The randomised controlled trial of 149 adults with a history of impaired hypoglycaemia awareness of severe hypoglycaemia found CGM reduced the incidence of hypoglycaemic events by 72% over six months follow-up.

The number of hypoglycaemic events per 28 days dropped from 10.8 to 3.5 with CGM compared to 14.4 to 13.7 with self-monitoring of blood glucose.

One third (33.3%) of the CGM participants had no hypoglycaemic events during follow-up compared to 7.6% of controls.

“This difference corresponds to an odds ratio of 6.1 for avoidance of hypoglycaemia in the rtCGM group compared with the control group,” the study authors said.

The number of nocturnal hypoglycaemic events also decreased in the GCM group as did the low blood glucose index.

Professor Stephen Twigg, head of endocrinology at Royal Prince Alfred Hospital, told the limbic the value of the study was that it targeted the people at highest risk.

“Many of the previous studies trying to look at the value of CGM have not studied those populations. They are the highest risk populations for severe hypoglycaemia because once a person has had one severe episode they are at higher risk of having another one within the next one or two years and reduced awareness of hypoglycaemia means they don’t get the early warning symptoms and they are at much higher risk too.”

“This study further supports the concept that in adults with type 1 diabetes who have these conditions of reduced hypo-awareness or those at much higher risk, CGM systems when used in a sensible manner can help a person to self manage, and markedly reduced the hypo rate.”

Adults with diabetes in need

Professor Twigg said about one in three people with diabetes have reduced awareness of hypoglycaemia – typically the people with longer duration of diabetes.

“So there are a lot of people in Australia who would benefit from some form of CGM that they could afford. At the moment it’s about $3,000 to $5,000 per person depending on the system they use.”

“This is one of the cornerstones of glucose management. We’ve got good insulin and insulin systems but neither the private insurers nor the government are at this stage picking up the tab in people above 21 years.”

The study found no difference in the incidence of severe hypoglycaemia requiring medical assistance.

“Despite all this technology, there may still be situation where some people are prone to get these very severe hypos. We have to recognize that some people might markedly overdose with insulin on occasion or have nothing to eat …so we can’t prevent all severe episodes.”

A commentary in The Lancet said real-time CGM can help individuals learn how their glucose levels change with meals, stress or exercise. The alarms in CGM systems were also helpful especially for people with impaired awareness of hypoglycaemia.

“CGM might be the best example of diabetes precision medicine widely available today since an individual’s daily glucose patterns are revealed at a glance and can effectively guide a clinician’s and a patient’s shared decision-making session.”