Aims

To describe the impact of a 12-month intervention using intermittently scanned continuous glucose monitoring (isCGM) on glycaemic control and glucose test frequency in adolescents and young adults with type 1 diabetes (T1D) and high-risk glycaemic control (HbA1c ≥75 mmol/mol [≥9.0%]).

Methods

In total, 64 young people (aged 13–20 years, 16.6 ± 2.1 years; 48% female; 41% Māori or Pacific ethnicity; mean diabetes duration 7.5 ± 3.8 years) with T1D were enrolled in a 6-month, randomized, parallel-group study comparing glycaemic outcomes from the isCGM intervention (n = 33) to self monitoring blood glucose (SMBG) controls (n = 31). In this 6-month extension phase, both groups received isCGM; HbA1c, glucose time-in-range (TIR), and combined glucose test frequency were assessed at 9 and 12 months.

Results

At 12 months, the mean difference in HbA1c from baseline was −4 mmol/mol [−0.4%] (95% confidence interval, CI: −8, 1 mmol/mol [−0.8, 0.1%]; p = 0.14) in the isCGM intervention group, and −7 mmol/mol [−0.7%] (95% CI: −16, 1 mmol/mol [−1.5, 0.1%]; p = 0.08) in the SMBG control group. No participants achieved ≥70% glucose TIR (3.9–10.0 mmol/L). The isCGM intervention group mean rate of daily glucose testing was highest at 9 months, 2.4 times baseline rates (p < 0.001), then returned to baseline by 12 months (incidence rate ratio = 1.4; 95% CI: 0.9, 2.1; p = 0.091).

Conclusions

The use of isCGM in young people with high-risk T1D resulted in transient improvements in HbA1c and glucose monitoring over a 9-month time frame; however, benefits were not sustained to 12 months.