Effectiveness of continuous glucose monitoring in adults with Type 2 diabetes treated with basal insulin

Key Takeaway
In patients with T2D and poor glycemic control receiving BI without prandial insulin, CGM vs BGM monitoring showed:
- Significantly greater improvement in -8month HbA 1c level
- Increased time in target glucose range of 70–180mg/dL
- Reduction in both time spent at >250 mg/dL and mean glucose level
Why This Matters
- Glucose monitoring is critical for safe and effective management of individuals with T2D using insulin
- As the role of CGM in T2D using less-intensive insulin regimens is not well defined; present study compared CGM vs BGM monitoring in this study population.
Study Design
This Multicenter, Randomized (N = 175 [CGM Or BGM Group: 2:1]), Open - Label, Parallel - Group Trial Was Conducted At 15 Centers In The United States*
Key inclusion criteria
- Age ≥30 years
- T2D treated with 1 or 2 daily injections of long- or intermediate-acting basal insulin for ≤6 months
- HbA 1c: 7.8%–11.5%
- Self-reported BGM testing: ≥3 times per week
- Smart phone compatible with CGM device†
Study outcomes
- Primary outcome: HbA1c level at 8 months (adjusted for BL value)
- Key secondary outcomes:
- Time in target glucose range of 70-180 mg/dL
- Time at glucose level >250 mg/dL
- Mean glucose level at 8 months (adjusted for BL value)
Key Result
A total of 175 participants were randomized (2:1) into CGM vs BGM group
(n = 116 vs 59; mean age = 57 years; mean BL HbA1c = 9.1%)
Primary outcome (cgm vs bgm group):
- HbA1c level at 8 months‡ 8.0% vs 8.4% (adjusted difference in mean change in HbA1c level from baseline:
- -0.4% [%95 CI: %0.8− to %0.1−; P = 0.02])
Key secondary outcomes (cgm vs bgm group):
- Time in target glucose range of 70-180 mg/dL (mean%): 59% vs 43% (adjusted mean difference: 15% [%95 CI: %8 to %23; P <0.001§])
- Time at glucose level >250 mg/dL (mean%):11% vs 27% (adjusted mean difference: −16% [%95 CI: %21− to %11−; P <0.001¶])
- Mean glucose levels at 8 months: 179 vs 206 mg/dL (adjusted difference: 26− mg/dL [%95 CI: 41− to 12−; P <0.001])
- ADVERSE EVENTS: Severe hypoglycemic event (one in both, CGM and BGM group) and diabetic ketoacidosis (one in CGM group)
- CGM satisfaction scale: Mean score (CGM group) = 4.1/5
Limitations
- Follow-up duration was only 8 months
- Due to virtual visits -8month HbA 1c or CGM data was not available for some participants
- Limited generalizability of study findings to most routine clinical practice settings
- In one-third of the CGM group HbA1c level still remained >%8 after 8 months highlighting the need for more aggressive pharmacological management
* Included participants not visiting an endocrinologist for diabetes and recruited participants from primary care practices.
† For data uploading.
‡Adjusted for BL values (mean BL HbA1c level [CGM vs BGM group] = %9.1 vs %9.0).
§ Equivalent to 3.6 hours more per day.
¶Equivalent to 3.8 hours less per day.
#The study participants had greater contact with the clinic staff vs typical usual care scenario
BL, baseline; BI, basal insulin; BGM, blood glucose meter; CGM, continuous glucose monitoring; CI, confidence interval; HbA1c, hemoglobin A1c; T2D, type 2 diabetes.
- Martens T, Beck RW, Bailey R, Ruedy KJ, Calhoun P, Peters AL, et al. Effect of continuous glucose monitoring on glycemic control in patients with type 2 diabetes treated with basal insulin: A randomized clinical trial. JAMA. 2272–2262:(22)325;2021. doi: 10.1001/jama.2021.7444. PMID: 34077499.