Intermittently Scanned CGM Reduced HbA1c in Type 1 Diabetes

Adults with uncontrolled type 1 diabetes saw a benefit when using intermittently scanned continuous glucose monitoring (CGM), the randomized FLASH-UK Trial showed.

Compared with traditional fingerstick testing, use of a intermittently scanned CGM, which offers optional alarms for high and low blood glucose levels set by the user, reduced HbA1c levels, with an adjusted mean between-group difference of -0.5 percentage points (95% CI -0.7 to -0.3, P<0.001) at 24 weeks, reported Lalantha Leelarathna, PhD, of the Manchester Royal Infirmary in England, and colleagues.

Specifically, the mean baseline HbA1c level was 8.7±0.9% in the intervention group and 8.5±0.8% in the usual-care group, which decreased to 7.9±0.8% and 8.3±0.9%, respectively, they noted in the New England Journal of Medicine.

“The improvements in glycated hemoglobin levels in the current trial are broadly similar to those in trials of real-time continuous glucose monitoring as compared with participants’ monitoring of their own blood glucose levels with the use of fingerstick testing,” Leelarathna and team wrote.

Users of the intermittently scanned CGM also spent 9% more time in target glycemic range (70-180 mg/dL), which was equal to 130 minutes more each day, versus the fingerstick group.

They also spent 3% less time in hypoglycemia (blood glucose under 70 mg/dL), equal to 43 fewer minutes each day, and 6% less time in hyperglycemia (blood glucose over 180 mg/dL), equal to 86 fewer minutes each day.

Overall, the average total daily insulin dose did not significantly differ between the groups, only dropping by 0.5 units per day for the CGM group.

Of note, users of the CGM saw a big improvement in treatment satisfaction as measured by the Diabetes Treatment Satisfaction Questionnaire. Compared with those using typical fingersticks, the CGM users saw a 7% increase in their satisfaction score.

Rates of adverse events were generally low for both groups, with two cases of severe hypoglycemia and two ketosis events not requiring hospitalization in the fingerstick group and one case of diabetic ketoacidosis in the CGM group. One CGM user also experienced a skin reaction to the sensor.

This multicenter open-label trial included 156 patients — 78 in each group — with type 1 diabetes and a baseline HbA1c between 7.5% and 11%. The minimum age for inclusion was 16, and the average participant age was 44. Nearly all participants were white.

The participants used Abbott’s FreeStyle Libre 2, which was first FDA cleared for use in patients 4 years and older in June 2020. By May of this year, the FDA also cleared the next-generation FreeStyle Libre 3 for these patients.

The glucose sensor, worn on the arm for 14 days, connects to a handheld device or free mobile app — first released in August 2021 — that displays both current and historical glucose data.

Most participants in each group used multiple daily insulin injections, while 26% of the CGM group and 31% of the fingerstick group used a continuous subcutaneous insulin infusion system.

Over a 24-hour period, the average number of sensor scans was 11 during the day and 1.3 at night. Data were not collected on alarm settings and use. As a result, Leelarathna and team said they couldn’t determine if these benefits were due to the sensor alone or also due to the optional alarms.