Sustained Benefit of Continuous Glucose Monitoring on A1C, Glucose Profiles, and Hypoglycemia in Adults With Type 1 Diabetes

OBJECTIVE: To evaluate long-term effects of continuous glucose monitoring (CGM) in intensively treated adults with type 1 diabetes. RESEARCH DESIGN AND METHODS: We studied 83 of 86 individuals ≥25 years of age with type 1 diabetes who used CGM as part of a 6-month randomized clinical trial in a subsequent 6-month extension study. RESULTS: After 12 months, median CGM use was 6.8 days per week. Mean change in A1C level from baseline to 12 months was −0.4 ± 0.6% (P < 0.001) in subjects with baseline A1C ≥7.0%. A1C remained stable at 6.4% in those with baseline A1C <7.0%. The incidence rate of severe hypoglycemia was 21.8 and 7.1 events per 100 person-years in the first and last 6 months, respectively. Time per day with glucose levels in the range of 71–180 mg/dl increased significantly (P = 0.02) from baseline to 12 months. CONCLUSIONS: In intensively treated adults with type 1 diabetes, CGM use and benefit can be sustained for 12 months.