The effect of real-time continuous glucose monitoring on glycemic control in patients with type 2 diabetes mellitus

J Diabetes Sci Technol. 2011 May 1;5(3):668-75. doi: 10.1177/193229681100500320.


Background: Real-time continuous glucose monitoring (RT-CGM) improves hemoglobin A1c (A1C) and hypoglycemia in people with type 1 diabetes mellitus and those with type 2 diabetes mellitus (T2DM) on prandial insulin; however, it has not been tested in people with T2DM not taking prandial insulin. We evaluated the utility of RT-CGM in people with T2DM on a variety of treatment modalities except prandial insulin.

Methods: We conducted a prospective, 52-week, two-arm, randomized trial comparing RT-CGM (n = 50) versus self-monitoring of blood glucose (SMBG) (n = 50) in people with T2DM not taking prandial insulin. Real-time continuous glucose monitoring was used for four 2-week cycles (2 weeks on/1 week off). All patients were managed by their usual provider. This article reports on changes in A1C 0-12 weeks.

Results: Mean (± standard deviation) decline in A1C at 12 weeks was 1.0% (± 1.1%) in the RT-CGM group and 0.5% (± 0.8%) in the SMBG group (p = .006). There were no group differences in the net change in number or dosage of hypoglycemic medications. Those who used the RT-CGM for ≥ 48 days (per protocol) reduced their A1C by 1.2% (± 1.1%) versus 0.6% (± 1.1%) in those who used it <48 days (p = .003). Multiple regression analyses statistically adjusting for baseline A1C, an indicator for usage, and known confounders confirmed the observed differences between treatment groups were robust (p = .009). There was no improvement in weight or blood pressure.

Conclusions: Real-time continuous glucose monitoring significantly improves A1C compared with SMBG in patients with T2DM not taking prandial insulin. This technology might benefit a wider population of people with diabetes than previously thought.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Blood Glucose / chemistry
  • Blood Glucose Self-Monitoring / methods*
  • Diabetes Mellitus, Type 1 / blood*
  • Diabetes Mellitus, Type 1 / therapy*
  • Diabetes Mellitus, Type 2 / blood*
  • Diabetes Mellitus, Type 2 / therapy*
  • Female
  • Glycated Hemoglobin A / analysis
  • Humans
  • Hypoglycemia / drug therapy
  • Insulin / metabolism
  • Male
  • Middle Aged
  • Prospective Studies
  • Regression Analysis
  • Treatment Outcome


  • Blood Glucose
  • Glycated Hemoglobin A
  • Insulin
  • hemoglobin A1c protein, human