The Relationship between A1C and Hypoglycemia in the Diamond Study Free

We revisited the well-known inverse relationship between A1C and hypoglycemia using data from phase 1 of the Diamond clinical trial that compared usual care to real-time continuous glucose monitoring (CGM) in subjects with type 1 diabetes using MDI and with A1C levels from 7.5% to 9.9%. Data from 157 subjects (104 and 53 in the CGM and control groups, respectively) were analyzed. The percentages of sensor glucose (SG) values ≤70 mg/dL (≤3.9 mmol/L) (“%≤70”) and of those indicating clinically significant hypoglycemia (≤54 mg/dL [≤3.0 mmol/L]) (“%≤54”) during the initial and final weeks of the 24-week study were calculated for each subject and compared to corresponding baseline and 24-week A1C values. At baseline, the percent ≤70 was similar for the two groups (p=0.24), as was the percent ≤54 (p=0.10). There was a trend toward more hypoglycemia for subjects near the minimum allowed A1C value of 7.5% (Figure A). At 24 weeks (Figure B), there were significant between-group differences in favor of CGM at both thresholds, and the association between decreasing A1C and increasing exposure to SG values ≤54 mg/dL was attenuated. Subjects in the CGM group averaged ∼16 minutes/day with SG ≤54 mg/dL. These data suggest patients with access to CGM alerts and alarms take appropriate and timely measures to nearly eliminate exposure to clinically meaningful hypoglycemia. CGM allows safe intensification of MDI therapy and achievement of near-normal A1C levels.