Use of Factory-Calibrated Real-time Continuous Glucose Monitoring Improves Time in Target and HbA1c in a Multiethnic Cohort of Adolescents and Young Adults with Type 1 Diabetes: the MILLENNIALS Study

Objective: Internationaltype 1 diabetes registries have shown that HbA1c levels are highest in youngpeople with type 1 diabetes, however improving their glycaemic control remainsa challenge. We propose that use of factory-calibratedDexcom G6 CGM system would improve glycaemic control in this cohort. Research Design andMethods: Weconducted a randomized crossover trial in young people with type 1 diabetes (16– 24 years old), comparing the Dexcom G6 CGM system and self-monitoring ofblood glucose (SMBG). Participants were assigned to the interventions in randomorder during two 8-week study periods. During SMBG, blinded CGM was worn byeach participant for 10 days at the start, week-4and week-7 of the control period. HbA1c measurements were drawn afterenrolment, before and after each treatment period. The primary outcome was timein range 70–180mg/dl.Results: Time inrange was significantly higher during CGM compared to control [35.7±13.5% vs. 24.6±9.3%,mean difference 11.1% (95% CI 7.0 to 15.2, p<0.001)]. CGM use reduced meansensor glucose [219.7±37.6mg/dl vs. 251.9±36.3mg/dl, mean difference -32.2mg/dl(95% CI -44.5 to -20.0, p<0.001)] and time above range [61.7±15.1% vs.73.6±10.4%, mean difference 11.9% (95% CI -16.4 to -7.4, p<0.001)]. HbA1clevel was reduced by 0.76% (95% CI -1.1 to -0.4) [-8.5mmol/mol (95% CI -12.4 to-4.6, p<0.001)]. Times spent belowrange (<70mg/dl and <54mg/dl) were low and comparable during both study periods.Sensor wear was 84% during the CGM period.Conclusion: CGM use inyoung people with type 1 diabetes improves time in target and HbA1c levelscompared to SMBG.