The introduction of fully subsidised continuous glucose monitoring (CGM) products in 2017 led to significant and sustained improvements in glycaemia among adolescents with type 1 diabetes, according to ‘real world’ data from Western Australia.

An observational study of 348 children with T1D attending Perth Children’s Hospital between January 2015 and July 2019 showed there was an immediate reduction in the upward trend in HbA1c levels among children following the commencement of CGM after 2017.

The analysis of pre- and post-CGM glycaemia was based on 3-monthly HbA1c measurements in children with a mean age of the children at CGM onset of 13.4 years and a mean duration of diabetes of 7.2 years.

Data was available for a mean 2.4 years pre-CGM and 1.2 years post–CGM duration and the mean HbA1c at CGM start was 8.5% (69 mmol/mol).

Prior to CGM there was on average a 0.29% increase per year in HbA1c levels. Following the start of CGM, there was a 0.39% decline in HbA1c levels and significant difference in the steepness of the slope of increase over time in HbA1c levels between pre-and post-CGM (difference -0.14%).

The introduction of CGM also led to a significant change in the trends for likelihood of achievement of target HbA1c <7% (53 mmol/mol). Prior to CGM the proportion of children achieving target over time was decreasing; whereas post-CGM the proportion of children with HbA1c in target range was significantly higher and maintained over time.

The improvements in glycaemia were seen across all children, with no significant differences based on socioeconomic status, insulin regimen, or duration of diabetes.

The study authors,led by Dr Elaine Sanderson of the Department of Diabetes and Endocrinology, Perth Children’s Hospital, said the findings aligned with results from randomised clinical trials and highlighted the value of providing subsidised access to CGM to all children with T1D.

“This real-world observational study shows an immediate and sustained reduction in HbA1c after commencement of CGM in a population-based cohort of children with T1D,” they wrote in Diabetes Care.

“This analysis shows that with subsidised CGM, improvement in HbA1c can be achieved irrespective of socioeconomic status. This is a point of difference from other real-world studies, as many countries do not provide universal subsidy for CGM and limit access to those who can afford the device.”

They acknowledged that the change in HbA1c seen was small, but emphasised that the sustained reduction in HbA1c trend overtime was a ‘critical’ finding.

“This is particularly important, considering the mean age of participants in this study was early adolescence, a time well-known for a decline in metabolic control.