Randomized Study of Real-Time Continuous Glucose Monitors (RT-CGM) in the Management of Type 1 Diabetes
![]() |
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT00406133 |
Recruitment Status :
Completed
First Posted : December 4, 2006
Results First Posted : September 2, 2009
Last Update Posted : April 14, 2017
|
- Study Details
- Tabular View
- Study Results
- Disclaimer
- How to Read a Study Record
Subjects with intensively-treated type 1 diabetes and glycated hemoglobin (HbA1c) 7.0%-10.0% in 3 age groups (>25, 15-24, 8-14) will be randomized to a continuous glucose monitoring (CGM) group or control group. The primary outcome is change in HbA1c after 26 weeks. A parallel randomized trial is being conducted for a second cohort with HbA1c <7.0% that will follow an identical protocol to that of the first cohort with HbA1c >=7.0%.
The >=7.0% trial was specifically designed and statistically powered to compare separately the impact of continuous versus standard intensive glucose monitoring in the three age groups. Both trials used standardized treatment algorithms and equivalent frequent contacts with subjects in both the CGM and control group.
After completion of the 26-week trial, the CGM group continues to use CGM for another 26 weeks to evaluate whether any beneficial effect seen in the first 6 months is sustained with longer-term use and less intensive contact and the control group initiates CGM use with less intensive contact after the first month than was provided at initiation of CGM use in the CGM group in the randomized trial.
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Type 1 Diabetes | Device: Continuous glucose monitor | Phase 3 |

Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 451 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | A Randomized Clinical Trial to Assess the Efficacy of Real-Time Continuous Glucose Monitoring (RT-CGM) in the Management of Type 1 Diabetes |
Study Start Date : | December 2006 |
Actual Primary Completion Date : | July 2008 |
Actual Study Completion Date : | February 2009 |

Arm | Intervention/treatment |
---|---|
No Intervention: Standard intensive glucose monitoring
Patients in the control group were given blood glucose meters and test strips and asked to perform home blood glucose monitoring at least four times daily.
|
|
Active Comparator: Continuous Glucose Monitoring (CGM)
Patients in the CGM group were instructed to use the CGM device on a daily basis and to verify the accuracy of the glucose measurement with a home blood glucose meter (provided by the study) before making management decisions (as per the regulatory labeling of the devices).
|
Device: Continuous glucose monitor
Daily use of a continuous glucose monitor
Other Names:
|
- Change in Glycated Hemoglobin (HbA1c) From Baseline to 26 Weeks in the Continuous Glucose Monitoring (CGM) and Control Groups (for the Cohort With Baseline HbA1c >=7.0% Cohort) [ Time Frame: Baseline and 26 weeks ]The primary outcome was the Change in glycated hemoglobin (HbA1c) from baseline to 26 weeks, as determined by a central laboratory (for the cohort with baseline HbA1c >=7.0% cohort).
- Time With Glucose Level <=70 mg/dL (for the Cohort With Baseline HbA1c <7.0%) [ Time Frame: Baseline and 26 weeks ]The primary outcome was the change in the time per day with glucose values <=70mg/dL comparing baseline sensor values with those obtained following the 26-week visit.
- Severe Hypoglycemia (for the Cohort With Baseline HbA1c >=7.0% Cohort) [ Time Frame: Baseline and 26 weeks ]Measure of the number of severe hypoglycemic events in the cohort with baseline HbA1c >=7.0% cohort
- Minutes Per Day Continuous Glucose Monitoring (CGM) Glucose Values 71-180 mg/dL (for the Cohort With Baseline HbA1c >=7.0% Cohort) [ Time Frame: Baseline and 26 weeks ]Data regarding CGM were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.
- Minutes Per Day Continuous Glucose Monitoring (CGM) Glucose Values >180 mg/dL (for the Cohort With Baseline HbA1c >=7.0% Cohort) [ Time Frame: Baseline and 26 weeks ]Data regarding CGM were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.
- Minutes Per Day Continuous Glucose Monitoring (CGM) Glucose Values >250 mg/dL (for the Cohort With Baseline HbA1c >=7.0% Cohort [ Time Frame: Baseline and 26 weeks ]Data regarding continuous glucose monitoring were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.
- Minutes Per Day Continuous Glucose Monitoring (CGM) Glucose Values <=70 mg/dL (for Cohort With Baseline HbA1c >=7.0%) [ Time Frame: Baseline and 26 weeks ]Data regarding continuous glucose monitoring in both groups after the 26-week visit were used to estimate the amount of time per day the glucose level was hypoglycemic (<=70 mg/dL)
- Minutes Per Day Continuous Glucose Monitoring (CGM) Glucose Values <=50 mg/dL (for Cohort With Baseline HbA1c >=7.0%) [ Time Frame: Baseline and 26 weeks ]Data regarding continuous glucose monitoring in both groups after the 26-week visit were used to estimate the amount of time per day the glucose level was hypoglycemic (<=50 mg/dL)
- Glucose (mg/dl) at Baseline and 26 Weeks (for Cohort With Baseline HbA1c >=7.0%) [ Time Frame: Baseline and 26 weeks ]Glucose variability was assessed by computing the absolute rate of change.
- Change in Glycated Hemoglobin (HbA1c) From Baseline to 26 Weeks in the Continuous Glucose Monitoring (CGM) and Control Groups (for the Cohort With Baseline HbA1c <7.0% Cohort) [ Time Frame: Baseline and 26 weeks ]The secondary outcome was the change in glycated hemoglobin (HbA1c) from baseline to 26 weeks in the Continuous Glucose Monitoring (CGM) and Control groups (for the cohort with baseline HbA1c <7.0% cohort), as determined by a central laboratory.
- Minutes Per Day of Continuous Glucose Monitoring (CGM) Glucose Values 71-180 mg/dL (for Cohort With Baseline HbA1c <7.0%) [ Time Frame: Baseline and 26 weeks ]Data regarding CGM were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.
- Minutes Per Day Continuous Glucose Monitoring (CGM) Glucose Values >180 mg/dL (for Cohort With Baseline HbA1c <7.0%) [ Time Frame: Baseline and 26 weeks ]Data regarding CGM were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.
- Minutes Per Day Continuous Glucose Monitoring (CGM) Glucose Values >250 mg/dL (for the Cohort With Baseline HbA1c <7.0% Cohort [ Time Frame: Baseline and 26 weeks ]Data regarding continuous glucose monitoring were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.
- Minutes Per Day Continuous Glucose Monitoring (CGM) Glucose Values <=50 mg/dL (for Cohort With Baseline HbA1c <7.0%) [ Time Frame: Baseline and 26 weeks ]Data regarding continuous glucose monitoring in both groups after the 26-week visit were used to estimate the amount of time per day the glucose level was hypoglycemic (<=50 mg/dL)
- Absolute Rate of Change (mg/dl/Min) at 26 Weeks (for Cohort With Baseline HbA1c <7.0%) [ Time Frame: Baseline and 26 weeks ]Glucose variability was assessed by computing the absolute rate of change.
- Quality of Life [ Time Frame: 26 weeks ]Hypoglycemia Fear Survey Total Score Average score of all items giving equal weight to each item. Scale 0-100 with higher score denoting more fear or more likely to avoid low blood glucose.
- Cost-effectiveness of CGM. [ Time Frame: 26 weeks ]Estimated total costs divided by estimated Quality-Adjusted Life Weeks (QALW) calculated per group
- QALW [ Time Frame: 26 weeks ]Quality Adjusted Life Weeks: We collected experienced utility data by eliciting time tradeoff (TTO) utilities for overall experience. Patients were asked to consider their current state of health in comparison to life in perfect health. Experienced utilities were elicited at baseline, 13 weeks, and 26 weeks. For children aged <18 years, parents served as surrogates. The total quality-adjusted life weeks (QALWs) were calculated as the area under the quality-of-life time trends under each arm.
- Total Costs: Direct and Indirect Costs [ Time Frame: 26 weeks ]Investigators reported time spent with patients on CGM training and diabetes management excluding research time. Adult patients (or caregivers of children) self-reported health service utilization including routine office visits, after-hours clinic visits, emergency room visits, 911 calls, and hospitalizations. The daily cost of CGM technology was calculated based on FDA recommended frequency of sensor replacement and the expected frequency of receiver and transmitter replacement. The costs of the three devices used during the trial were averaged to arrive at a daily cost of CGM of $13.85. This daily cost was multiplied by the reported weekly use of CGM to arrive at an overall cost of CGM technology. Indirect costs: self-reported number of hours devoted to diabetes care per day, number of days missed from work or school due to diabetes, and number of days of work underperformance. Unit costs available at: http://care.diabetesjournals.org/cgi/content/full/dc09-2042/DC1 (Table 1).
- Relative Decrease in A1c Level by >=10% (for Cohort With Baseline HbA1c >=7.0%) [ Time Frame: Baseline and 26 weeks ]A relative decrease in A1c level >=10% was evaluated in logistic-regression models, adjusted for the baseline glycated hemoglobin level and clinical center.
- Relative Increase in A1c Level by >=10% (for Cohort With Baseline HbA1c >=7.0%) [ Time Frame: Baseline and 26 weeks ]A relative increase in A1c level by >=10% was evaluated in logistic-regression models, adjusted for the baseline glycated hemoglobin level and clinical center.
- Relative Decrease in A1c Level by >=0.5% (for Cohort With Baseline HbA1c >=7.0%) [ Time Frame: Baseline and 26 weeks ]A relative decrease A1c level by >=0.5% was evaluated in logistic-regression models, adjusted for the baseline glycated hemoglobin level and clinical center.
- Relative Increase in A1c Level by >=0.5% (for Cohort With Baseline HbA1c >=7.0%) [ Time Frame: Baseline and 26 weeks ]A relative increase by in A1c level >=0.5% was evaluated in logistic-regression models, adjusted for the baseline glycated hemoglobin level and clinical center.
- 26-week A1c Level <7.0% (for Cohort With Baseline HbA1c >=7.0%) [ Time Frame: Baseline and 26 weeks ]A 26-week A1c level <7.0% was evaluated in logistic-regression models, adjusted for the baseline glycated hemoglobin level and clinical center.
- Decrease in A1c From Baseline by >=0.3% (for Cohort With Baseline HbA1c <7.0%) [ Time Frame: Baseline and 26 weeks ]Other preplanned secondary outcomes included change in HbA1c from baseline to 26 weeks in an ANCOVA model (adjusted for baseline HbA1c and clinical center) and 26-week binary HbA1c outcomes evaluated similarly in logistic regression models.
- Increase in A1c From Baseline by >=0.3% (for Cohort With Baseline HbA1c <7.0%) [ Time Frame: Baseline and 26 weeks ]Other preplanned secondary outcomes included change in HbA1c from baseline to 26 weeks in an ANCOVA model (adjusted for baseline HbA1c and clinical center) and 26-week binary HbA1c outcomes evaluated similarly in logistic regression models.
- 26-week A1c Level <7.0% (for Cohort With Baseline HbA1c <7.0%) [ Time Frame: Baseline and 26 weeks ]Other preplanned secondary outcomes included change in HbA1c from baseline to 26 weeks in an ANCOVA model (adjusted for baseline HbA1c and clinical center) and 26-week binary HbA1c outcomes evaluated similarly in logistic regression models.

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 8 Years and older (Child, Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
-
Clinical diagnosis of type 1 diabetes and using daily insulin therapy for at least one year
- The diagnosis of type 1 diabetes is based on the investigator's judgment; C peptide level and antibody determinations are not needed.
- Age >8 years
-
Glycated hemoglobin(HbA1c) 7.0%-10.0% for the primary cohort and <7.0% for the secondary cohort
- The DCA2000 or comparable point of care device will be used to assess eligibility.
-
Insulin regimen involves either use of an insulin pump or multiple daily injections of insulin (at least 3 shots per day) and has been stable for the last two months, with no plans to switch the modality of insulin administration during the next 6 months (e.g., injection user switching to a pump, pump user switching to injections, or the addition of Lantus (Glargine) insulin)
- Subjects using premixed fixed doses of insulin at the time of enrollment will not be eligible
- Subject (and parent/guardian for children) understands the study protocol and agrees to comply with it
-
Subjects >9 years old and primary care giver (i.e., parent or guardian if subject is a minor) comprehend written English or Spanish
- This requirement is due to the fact that the questionnaires to be used as outcome measures do not have validated versions in other languages.
- Spanish-speaking subjects will be enrolled only if a RT-CGM device that functions in Spanish and has a User Guide in Spanish is available.
- No expectation that subject will be moving out of the area of the clinical center during the next year, unless the move will be to an area served by another study center.
- Informed Consent Form signed by the subject (or parent/guardian if subject is a minor, with subject signing the Child Assent Form)
Exclusion Criteria:
- The presence of a significant medical disorder or use of a medication such as oral/inhaled glucocorticoids that in the judgment of the investigator will affect the wearing of the sensors or the completion of any aspect of the protocol.
-
The presence of any of the following diseases:
- Asthma if treated with systemic or inhaled corticosteroids in the last 6 months
- Cystic fibrosis
- Adequately treated thyroid disease and celiac disease do not exclude subjects from enrollment
- Inpatient psychiatric treatment in the past 6 months (if the subject is a minor, for either the subject or the subject's primary care giver).
-
Home use of RT-CGM in past 6 months
- Use of a CGMS or GlucoWatch does not exclude subjects from enrollment
- Participation in an intervention study (including psychological studies) in past 6 weeks.
- Another member of the same household is participating in this study.
- For females, pregnant or intending to become pregnant during the next year Pregnancy is an exclusion because of uncertainty about the lag between interstitial fluid glucose and blood glucose during pregnancy, which might affect the accuracy of the sensor. Subjects who become pregnant during the study will be discontinued from the study.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00406133
United States, California | |
University of Southern California | |
Beverly Hills, California, United States, 90211 | |
Kaiser Permanente | |
San Diego, California, United States, 92111 | |
Stanford University | |
Stanford, California, United States, 94305 | |
United States, Colorado | |
University of Colorado | |
Aurora, Colorado, United States, 80010 | |
United States, Connecticut | |
Yale University School of Medicine | |
New Haven, Connecticut, United States, 06520 | |
United States, Florida | |
Nemours Children's Clinic | |
Jacksonville, Florida, United States, 32207 | |
United States, Georgia | |
Atlanta Diabetes Associates | |
Atlanta, Georgia, United States, 30309 | |
United States, Iowa | |
Children's Hospital of Iowa | |
Iowa City, Iowa, United States, 52242 | |
United States, Massachusetts | |
Joslin Diabetes Center - Adults | |
Boston, Massachusetts, United States, 02215 | |
Joslin Diabetes Center - Children | |
Boston, Massachusetts, United States, 02215 | |
United States, Washington | |
University of Washington | |
Seattle, Washington, United States, 98105 |
Study Director: | Roy W Beck, MD, PhD | Jaeb Center for Health Research | |
Study Chair: | Lori Laffel, MD | Joslin Diabetes Center Pediatric Section | |
Study Chair: | William V. Tamborlane, MD | Yale University |
Other Publications:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Jaeb Center for Health Research |
ClinicalTrials.gov Identifier: | NCT00406133 |
Other Study ID Numbers: |
2006-2402 |
First Posted: | December 4, 2006 Key Record Dates |
Results First Posted: | September 2, 2009 |
Last Update Posted: | April 14, 2017 |
Last Verified: | March 2017 |
Diabetes Mellitus Diabetes Mellitus, Type 1 Glucose Metabolism Disorders Metabolic Diseases |
Endocrine System Diseases Autoimmune Diseases Immune System Diseases |