Clinical Edge

Summaries of Must-Read Clinical Literature, Guidelines, and FDA Actions

Continuous Glucose Monitoring in Patients with T2D

Ann Intern Med; ePub 2017 Aug 22; Beck, et al

A high percentage of patients receiving multiple daily insulin injections for type 2 diabetes (T2D) using continuous glucose monitoring (CGM) on a daily basis or near daily basis for 24 weeks had improved glycemic control, a recent study found. The randomized clinical trial included patients from 25 endocrinology practices in North America. 153 adults with T2D (aged 35-79 years) for a median of 17 years and who were receiving multiple daily injections of insulin, and had HbA1c levels of 7.5% to 9.9%, were included. Patients were randomly assigned to CGM (n=79) or usual care (n=79). Primary outcome was HbA1c reduction at 24 weeks. Researchers found:

  • Mean HbA1c levels decreased to 7.7% in the CGM group vs 8.0% in the control group at 24 weeks.
  • The groups did not differ significantly in CGM-measured hypoglycemia or quality-of-life outcomes.
  • The CGM group averaged 6.7 days of CGM use per week.


Beck RW, Riddlesworth TD, Ruedy K, et al. Continuous glucose monitoring versus usual care in patients with type 2 diabetes receiving multiple daily insulin injections: A randomized trial. [Published online ahead of print August 22, 2017]. Ann Intern Med. doi:10.7326/M16-2855.


Clearly, CGM gives motivated patients a better perspective on the details of their blood sugar control and on what actions influence their blood sugar results. CGM has been shown to be very beneficial for patients with type 1 diabetes, with one study showing an A1c improvement of 0.6% compared to self-monitoring of blood glucose with test strips.1 It makes sense that CGM would be helpful for patients with advanced type 2 diabetes who are glucose deficient and on multiple insulin injections daily. The benefit in this well-done study was an A1c difference of 0.3% favoring CMG. The challenge to CGM is that it requires motivated patients; even in the carefully selected group enrolled in this study (consisting, we can assume, of patients whom the investigators thought could manage CGM), almost a quarter of patients did not ultimately qualify to continue, many due to an inability to wear the CGM as often as required and to calibrate the CGM the necessary twice a day. In addition, one wonders whether the benefit would be sustained past 24 weeks as motivation to do CGM wanes. That all said, this study supports the contention that for some motivated patients with type 2 diabetes on basal-bolus insulin regimens, CGM provides a modest benefit in A1c improvement compared to standard test strip monitoring. —Neil Skolnik, MD

  1. Beck RW, Riddlesworth T, Ruedy K, et al; DIAMOND Study Group. Effect of continuous glucose monitoring on glycemic control in adults with type 1 diabetes using insulin injections: the DIAMOND randomized clinical trial. JAMA. 2017;317:371-378. doi:10.1001/jama.2016 .19975.