Effect of 6 Months of Flash Glucose Monitoring in Youth With Type 1 Diabetes and High-Risk Glycemic Control: A Randomized Controlled Trial

To investigate whether intermittently scanned continuous glucose monitoring (isCGM) significantly improves glycemic control compared with capillary self-monitored blood glucose (SMBG) in youth with type 1 diabetes and high-risk glycemic control. This multicenter 6-month randomized, controlled, parallel-arm trial included 64 participants aged 13-20 years with established type 1 diabetes and glycated hemoglobin (HbA ) ≥9% (≥75 mmol/mol). Participants were allocated to 6-month intervention (isCGM; FreeStyle Libre; Abbott Diabetes Care, Witney, U.K.) ( = 33) or control (SMBG; = 31) using minimization. The primary outcome was the difference in change in HbA from baseline to 6 months. There was no evidence of a difference between groups for changes in HbA at 6 months (adjusted mean 0.2% greater improvement for isCGM [95% CI -0.9 to 0.5] [-2.1 mmol/mol (95% CI -9.6 to 5.4)]; = 0.576). However, glucose-monitoring frequency was 2.83 (95% CI 1.72-4.65; < 0.001) times higher in the isCGM group compared with that in the SMBG group at 6 months. The change in the Diabetes Treatment Satisfaction Questionnaire mean item score also favored isCGM at 6 months ( = 0.048), with no significant differences between groups for fear of hypoglycemia and quality of life (both general and diabetes specific) (all > 0.1). For youth with high-risk glycemic control, isCGM led to improvements in glucose testing frequency and diabetes treatment satisfaction. However, these did not translate to greater improvement in glycemic control over usual care with SMBG at 6 months.