The Effect of Continuous Glucose Monitoring in Well-controlled Type 1 Diabetes

  1. Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group


    Objective: The potential benefits of continuous glucose monitoring (CGM) in the management of adults and children with well controlled type 1 diabetes have not been examined.

    Research Design and Methods: 129 adults and children with intensively-treated type 1 diabetes (age range 8 to 69 years) and HbA1c <7.0% were randomly assigned to either continuous or standard glucose monitoring for 26 weeks. The main study outcomes were time with glucose level ≤70 mg/dL, HbA1c level, and severe hypoglycemic events.

    Results: At 26 weeks, biochemical hypoglycemia (≤70 mg/dL) was less frequent in the CGM group than the control group (median 54 versus 91 minutes/day) but the difference was not statistically significant (P=0.16). Median time with a glucose level ≤60 mg/dL was 18 versus 35 minutes/day, respectively (P=0.05). Time out of range (≤70 or >180 mg/dL) was significantly lower in the CGM group than the control group (377 versus 491 minutes per day, P=0.003). There was a significant treatment group difference favoring the CGM group in mean HbA1c at 26 weeks adjusted for baseline (P<0.001). One or more severe hypoglycemic events occurred in 10% and 11% of the two groups, respectively (P=1.0). Four outcome measures combining HbA1c and hypoglycemia data favored the CGM group in comparison with the control group (P<0.001, 0.007, 0.005, and 0.003).

    Conclusions: Most outcomes, including those combining HbA1c and hypoglycemia, favored the CGM group. The weight of evidence suggests that CGM is beneficial for individuals with type 1 diabetes who have already achieved excellent control with HbA1c <7.0%.


      • Received January 20, 2009.
      • Accepted April 27, 2009.

    This Article

    1. Diabetes Care
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