Continuous glucose monitoring (CGM) was associated with better glycemic control than blood glucose meter (BGM) monitoring, according to results of a randomized clinical trial that were published in JAMA.

Adults (N=175) with type 2 diabetes who had poor glycemic control were recruited at 15 centers in the United States from July 30, 2018, to October 30, 2019. Prior to randomization, participants used a CGM device that recorded glucose trends for up to 10 days.

Participants were randomly assigned in a 2:1 ratio to continue using the CGM or to switch to a BGM. The CGM group used a Dexcom G6 CGM System that assessed blood glucose every 5 minutes, and the BGM group was instructed to test fasting and postprandial glucose 1 to 3 times daily.

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Patients in the CGM and BGM cohorts had a mean age of 56 (SD, 9) and 59 (SD, 9) years, 53% and 46% were women, 43% and 56% were White, they had been diagnosed with diabetes 14 (SD, 9) and 15 (SD, 10) years previously, and hemoglobin A1c (HbA1c) at baseline was 9.2% (SD, 1.0%) and 9.0% (SD, 0.9%), respectively.

At 8 months, HbA1c had decreased to 8.0% (SD, 1.4%) in the CGM and 8.4% (SD, 1.3%) in the BGM cohorts (P =.02).

The CGM cohort was associated with increased time in the 70 to 180 mg/dL glucose range (risk-adjusted difference [RAD], 15%; 8% to 23%; P <.001), decreased time in the >250 mg/dL glucose range (RAD, -16%; 95% CI, -21% to -11%; P <.001), decreased mean glucose (RAD, -26 mg/dL; 95% CI, -41 to -12 mg/dL; P <.001), and decreased time in the <54 mg/dL glucose range (RAD, -0.10%; 95% CI, -0.15% to -0.04%; P =.001).

Using CGM did not lead to a decreased use of diabetes medications or a lower total daily insulin dose.

At least 1 adverse event was reported by 26% and 20% of the participants in the CGM and BGM cohorts, respectively. Serious adverse events were reported by 9% of each group, severe hypoglycemic events by 1 participant in each group, and 1 diabetic ketoacidosis event by a participant in the CGM cohort.

This study may have been limited by the fact that some of the 8-month follow-up visits were performed virtually due to the COVID-19 pandemic.

These data indicated that patients with type 2 diabetes who had poor glycemic control may have achieved more stable blood glucose concentrations by using a CGM system.

Disclosure: This research was supported by Dexcom Inc. Please see the original reference for a full list of disclosures.


Martens T, Beck RW, Bailey R, et al; MOBILE Study Group. Effect of continuous glucose monitoring on glycemic control in patients with type 2 diabetes treated with basal insulin: a randomized clinical trial. JAMA. 2021;325(22):2262-2272. doi:10.1001/jama.2021.7444

This article originally appeared on Endocrinology Advisor