Sustained Benefit of Continuous Glucose Monitoring on A1C, Glucose Profiles, and Hypoglycemia in Adults With Type 1 Diabetes

  1. The Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group*
  1. Corresponding author: Roy W. Beck, jdrfapp{at}


OBJECTIVE To evaluate long-term effects of continuous glucose monitoring (CGM) in intensively treated adults with type 1 diabetes.

RESEARCH DESIGN AND METHODS We studied 83 of 86 individuals ≥25 years of age with type 1 diabetes who used CGM as part of a 6-month randomized clinical trial in a subsequent 6-month extension study.

RESULTS After 12 months, median CGM use was 6.8 days per week. Mean change in A1C level from baseline to 12 months was −0.4 ± 0.6% (P < 0.001) in subjects with baseline A1C ≥7.0%. A1C remained stable at 6.4% in those with baseline A1C <7.0%. The incidence rate of severe hypoglycemia was 21.8 and 7.1 events per 100 person-years in the first and last 6 months, respectively. Time per day with glucose levels in the range of 71–180 mg/dl increased significantly (P = 0.02) from baseline to 12 months.

CONCLUSIONS In intensively treated adults with type 1 diabetes, CGM use and benefit can be sustained for 12 months.


  • *The members of the Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group are included in the appendix. A complete list of the clinical centers and investigators is available in the online appendix at

  • Clinical trial reg. no. NCT00406133,

  • The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

    • Received May 7, 2009.
    • Accepted July 29, 2009.
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  1. Diabetes Care vol. 32 no. 11 2047-2049
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