301-OR: The Impact of Continuous Glucose Monitoring in Youth with Type 1 Diabetes, Aged 16-21

Background: People with T1DM under 21 are eligible for subsidised continuous glucose monitoring (CGM) products under the Australian National Diabetes Services Scheme. There are few “real world” published studies to evaluate the benefits of CGM in young adults.

Aim: To determine whether CGM is associated with improvement in glycaemic markers amongst eligible T1DM patients.

Methods: Patients at the Westmead Hospital young adult diabetes clinic aged 16-21 who commenced CGM prior to July 2018 were followed-up for 6 months after CGM commencement. Differences in HbA1c and glucose metrics at baseline and follow-up are compared between those started on CGM and those who were not.

Results: There were 115 eligible patients, of which 38% (n=44) commenced CGM. There were no differences in age, gender or baseline HbA1c of those started on CGM vs. those who were not. CGM users were more likely to use CSII than MDI (n=27 vs. 17, P=0.02), and came from post code areas which had higher median household incomes, despite fully subsidised CGM costs. At 6 months follow-up, only 41% (n=18/44) were confirmed to still be using CGM, with common reasons for dropout being discomfort, inconvenience, and disruptive alarms. Of those who continued, there was no change from baseline to 6 months in HbA1c (8.2±1.3% vs. 8.3±1.5%, P=0.7), coefficient of variation of glucose (0.39 vs. 0.38, P=0.5), or % time in range (54% vs. 58%, P=0.3), with average CGM wear time 65% in the 4 weeks prior to follow-up visit. At 6 months there was a weak correlation between percentage use of CGM and HbA1c reduction (R=0.46, P=0.07). Mean hypoglycaemia fear scores (worry scale) was significantly decreased from baseline at 6 months (33 vs. 18, P<0.01).

Conclusion: There are high rates of discontinuation in CGM use amongst T1DM patients aged 16-21. At six months of use there was no significant improvement in glycaemic control, although higher CGM usage was weakly correlated with increased time in range. Worry of hypoglycaemia was significantly decreased amongst those who continued CGM.