Hypoglycemic Event Frequency and the Effect of Continuous Glucose Monitoring in Adults with Type 1 Diabetes Using Multiple Daily Insulin Injections

INTRODUCTION: The benefits of continuous glucose monitoring (CGM) in type 1 diabetes have been established among adults using insulin pumps. The DIAMOND randomized clinical trial examined the effectiveness of using CGM in improving glycemic control in participants using insulin injections. The frequency of hypoglycemic events in this trial has not been previously examined. METHODS: Adults with type 1 diabetes using multiple daily insulin injections (MDI) with A1C values of 7.5% to 9.9% and not using CGM were randomized to adopt CGM (CGM group, n = 105) or continue with usual care (control group, n = 53). CGM data were collected from both groups at the beginning of the study and after 3 and 6 months. A hypoglycemic event was defined as a series of at least CGM values less than 3.0 mmol/L, separated by 20 min or more, with no intervening values of 3.0 mmol/L or more. Hypoglycemic event rates per 24 h were compared using a linear model adjusted for the baseline event rate per 24 h, baseline A1C, and site as a random effect. RESULTS: In the CGM group, the median hypoglycemic event rate fell by 30% (0.23 per 24 h at baseline and 0.16 per 24 h at follow-up) while in the control group the rate was nearly unchanged (0.31 per 24 h at baseline and 0.30 per 24 h at follow-up; p value = 0.03). CONCLUSION: In the DIAMOND randomized controlled trial, participants in the CGM group experienced a greater reduction in hypoglycemic event rate than participants receiving usual care in the control group. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT02282397.