Originally published by 2 Minute Medicine^® (view original article). Reused on AccessMedicine with permission.

1. Among adults with poorly controlled type 2 diabetes treated with basal insulin without prandial insulin, continuous glucose monitoring resulted in significantly lower hemoglobin A_1c levels at 8 months when compared with conventional blood glucose meter monitoring.

2. Patients using continuous glucose monitoring also had significantly improved secondary outcomes including a higher mean percentage of time in the target glucose range, a lower mean percentage of time in the high-risk range, and a lower average of mean glucose values.

Evidence Rating Level: 1 (Excellent)

Study Rundown:

Glucose monitoring is crucial for the safe and effective management of individuals with type 2 diabetes using insulin. Conventionally, glucose management based on blood glucose meter (BGM) monitoring has been the standard of care in individuals with type 2 diabetes using insulin and has been shown to be effective in treat-to-target trials and observational studies. More recently, real-time continuous glucose monitoring (CGM) in individuals with type 1 diabetes has demonstrated the potential to better inform diabetes management decisions compared to episodic self-monitoring via BGM by providing vital information such as glucose measurements every 5 minutes, hypo- and hyperglycemic alerts, and glucose trend information. However, the use of CGM in type 2 diabetes treated with basal insulin without prandial insulin has not been well studied. In order to evaluate the effectiveness of CGM in these patients, an 8-month randomized, multicenter, clinical trial was conducted comparing CGM with BGM monitoring in patients with type 2 diabetes treated with basal insulin without prandial insulin whose diabetes was being managed by primary care clinicians. The primary outcome measured was hemoglobin A_1c (HbA_1c) level at 8 months. Secondary outcomes included time in target glucose range (70 to 180 mg/dL), time with glucose level > 250 mg/dL, and mean glucose level at 8 months. Among 175 participants randomly assigned in a 2:1 ratio of 116 patients using CGM and 59 patients using traditional BGM monitoring, there was a significantly greater decrease in HbA_1c level over 8 months with CGM (9.1% at baseline to 8.0% at 8 months; −1.1%) compared to BGM monitoring (9.0% to 8.4%; −0.6%). A limitation of this study was that the duration of follow-up was only 8 months and thus, it was unknown whether the high degree of CGM use and glycemic benefits could be sustained for a longer duration. A 6-month extension phase of the study may potentially provide more insights in this regard.

Click to read the study in JAMA

Click to read an accompany editorial in JAMA

Relevant Reading: Continuous glucose monitoring vs conventional therapy for glycemic control in adults with type 1 diabetes treated with multiple daily insulin injections: the GOLD randomized clinical trial

In-Depth [randomized controlled trial]:

This multicenter, randomized, open-label, parallel-group clinical trial was conducted at 15 centers in the United States with enrollment spanning from July 2018 to October 2019 and an 8-month follow-up period completed in July 2020. The study included adults with poorly controlled type 2 diabetes receiving their diabetes care from a primary care clinician and treated with 1 or 2 daily injections of long- or intermediate-acting basal insulin without prandial insulin, with or without noninsulin glucose-lowering medications. In total, 175 patients were randomized for glucose monitoring via CGM (116 patients) or BGM (59 patients). The mean [SD] age was 57 [9] years, where 88 were women [50%], 92 self-identified as individuals of racial/ethnic minorities [53%], and 165 (94%) completed the trial. At baseline, the mean [SD] HbA_1c level was 9.1% [0.9%]. In the CGM cohort, the mean HbA_1c level decreased from 9.1% at baseline to 8.0% at 8 months in contrast to 9.0% to 8.4% in the BGM cohort (adjusted difference, −0.4% [95%CI, −0.8% to −0.1%]; P = .02). For key secondary outcomes, the CGM cohort, as compared with BGM, yielded a higher mean percentage of CGM-measured time in the target glucose range of 70 to 180 mg/dL (59% vs 43%; adjusted difference, 15% [95%CI, 8% to 23%]; P < .001), a lower mean percentage of time at high-risk glucose range of greater than 250 mg/dL (11% vs 27%; adjusted difference, −16% [95%CI, −21% to −11%]; P < .001), and a lower average of mean glucose values (179 mg/dL vs 206 mg/dL; adjusted difference, −26 mg/dL [95%CI, −41 to −12]; P < .001). Lastly, severe hypoglycemic events occurred in 1 participant (1%) in the CGM cohort and 1 participant (2%) in the BGM cohort.

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