CGM Intervention in Teens and Young Adults With Type 1 Diabetes (T1D) (CITY)
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ClinicalTrials.gov Identifier: NCT03263494 |
Recruitment Status :
Completed
First Posted : August 28, 2017
Last Update Posted : March 3, 2020
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Condition or disease | Intervention/treatment | Phase |
---|---|---|
Type 1 Diabetes Mellitus | Device: Continuous Glucose Monitor (CGM) | Phase 3 |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 153 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | CGM Intervention in Teens and Young Adults With T1D (CITY): A Randomized Clinical Trial to Assess the Efficacy and Safety of Continuous Glucose Monitoring in Young Adults 14-<25 With Type 1 Diabetes |
Actual Study Start Date : | January 25, 2018 |
Actual Primary Completion Date : | May 8, 2019 |
Actual Study Completion Date : | November 7, 2019 |

Arm | Intervention/treatment |
---|---|
Active Comparator: CGM |
Device: Continuous Glucose Monitor (CGM)
Participants randomized to the CGM Group will receive a Dexcom CGM device and be instructed on how to utilize the CGM data in real time for diabetes management. |
No Intervention: BGM |
- Change in HbA1c from baseline to 26 weeks adjusted for baseline [ Time Frame: 6 months ]
- % with HbA1c <7.0% [ Time Frame: 6 months ]
- % with HbA1c <7.5% [ Time Frame: 6 months ]
- % with relative reduction ≥ 10% [ Time Frame: 6 months ]
- % with absolute reduction ≥ 0.5% [ Time Frame: 6 months ]
- % with absolute reduction ≥ 1% [ Time Frame: 6 months ]
- % with absolute reduction ≥ 1% or HbA1c < 7.0% [ Time Frame: 6 months ]
- CGM % time in range 70-180 mg/dl [ Time Frame: 6 months ]
- CGM mean glucose [ Time Frame: 6 months ]
- CGM glucose variability measured by coefficient of variation [ Time Frame: 6 months ]
- CGM % time > 180 mg/dl [ Time Frame: 6 months ]
- CGM % time > 300 mg/dl [ Time Frame: 6 months ]
- CGM % time < 54 mg/dl [ Time Frame: 6 months ]
- CGM % time < 70 mg/dl [ Time Frame: 6 months ]
- Rate of CGM measured hypoglycemic episodes (using <54 mg/dL) [ Time Frame: 6 months ]
- CGM Self Efficacy Questionnaire Score [ Time Frame: 6 months ]Questionnaire containing 15 questions with possible responses 0-6. Total score is calculated by taking the mean of the non-missing responses. Then multiply by 100 and divide by 6 to put on the scale 0-100. Higher total score indicates higher perceived ability.
- Problem Areas in Diabetes (PAID) Questionnaire Score [ Time Frame: 6 months ]Survey containing 20 questions with possible responses 0-5. Total score is calculated by taking the mean of the non-missing items and multiplying by 20 to put on the scale 0-100. A higher total score indicates more of a problem.
- Glucose Monitoring Satisfaction Questionnaire Score [ Time Frame: 6 months ]Survey containing 15 questions. Total score ranges from 0-100. A higher total score indicates more satisfaction with their current glucose monitor.
- Hypoglycemia Confidence Questionnaire Score [ Time Frame: 6 months ]Survey containing 9 questions with possible responses 0-4. Total score is calculated by taking the mean of non-missing responses and multiplying by 25 to put on the scale 0-100. Higher total score indicates more confidence.
- Diabetes Technology Attitudes Questionnaire Score [ Time Frame: 6 months ]Survey containing 5 questions with possible responses 0-4. Total score is calculated by taking the mean of non-missing responses and multiplying by 25 to put on the scale 0-100. Higher total score indicates a more positive attitude towards diabetes technology.
- Pittsburgh Sleep Quality Index [ Time Frame: 6 months ]Survey containing 19 questions. Total score ranges from 0-21. A lower score indicates a healthier sleep quality.

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: | 14 Years to 24 Years (Child, Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Clinical diagnosis of T1D, with either age of T1D diagnosis < 10 years of age OR a history of positive T1D related antibodies in the medical record
- Age 14-<25 years
- Diabetes duration ≥ 1 year
- Total daily insulin requirement ≥ 0.4 units/kg/day
- HbA1c 7.5% to <11.0% (Point of care device or local lab measured as part of study at screening visit)
- Insulin regimen involves a consistent modality of insulin administration with either use of an insulin pump or at least 3 multiple daily injections of basal and bolus (meal time) analogue insulin. Insulin pump must not have been started within 3 months of consent with no plans to change regimens in the next 6 months
- Perform at least 2 blood glucose meter checks per day from self-report at screening and an average of at least 2 checks per day from meter download during blinded CGM run in
- Blinded CGM must be used a minimum of 200 hours (equivalent to 8.3 days) with an average of 1.8 calibrations per day during the blinded CGM screening period.
- Participant comprehends written and spoken English
- Participant understands the study protocol and agrees to it (if applicable)
Exclusion Criteria:
- Use of unblinded personal CGM and/or flash CGM, outside of a research study, as part of real-time diabetes management in the last 3 months
- Unable to use CGM device for minimum number of hours during blinded pre-randomization period or skin reaction from adhesive that would preclude participation in the randomized trial
- Started on non-insulin medication for blood glucose control within the past 3 months or plans to begin within the next 6 months
- The presence of a significant medical disorder that in the judgment of the investigator will affect the wearing of the sensors (such as a skin condition), or the completion of any aspect of the protocol.
- More than 1 episode of DKA in the past 6 months as defined in the adverse events chapter.
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The presence of any of the following diseases:
- Asthma or any condition present in the last 6 months where treatment is a systemic or daily inhaled corticosteroid (Intermittent treatment with inhaled corticosteroids does not exclude subjects from enrollment)
- Cystic fibrosis
- Addison's disease (Adequately treated thyroid disease and celiac disease do not exclude subjects from enrollment)
- Inpatient psychiatric treatment in the past 6 months or daily intensive outpatient psychiatric day treatment in the past 3 months.
- Pregnant (positive test confirmed at screening) or planning to become pregnant in the next 12 months.
- Need for use of acetaminophen or acetaminophen-containing products on a regular basis during the 6 months of the trial
- Participation in a diabetes related intervention study in the past 6 weeks.
- Any medical, psychological or social situation where per investigator discretion it may be difficult for participant to participate fully in the intervention
- Any condition, per investigator assessment, that could impact reliability of the A1C measurement, such as (but not limited to) hemoglobinopathy, hemolytic anemia, chronic liver disease; chronic GI blood loss, red blood cell transfusion or erythropoietin administration within 3 months prior to screening

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): NCT03263494
United States, California | |
Children's Hospital Los Angeles | |
Los Angeles, California, United States, 90027 | |
Stanford University | |
Palo Alto, California, United States, 94304 | |
United States, Colorado | |
Barbara Davis Center--University of Colorado | |
Aurora, Colorado, United States, 80045 | |
United States, Connecticut | |
Yale University | |
New Haven, Connecticut, United States, 06511 | |
United States, Idaho | |
Rocky Mountain Diabetes & Osteoporosis Center | |
Idaho Falls, Idaho, United States, 83404 | |
United States, Massachusetts | |
Joslin Diabetes Center | |
Boston, Massachusetts, United States, 02215 | |
United States, Minnesota | |
IDC at Park Nicollet | |
Saint Louis Park, Minnesota, United States, 55416 | |
United States, Missouri | |
Children's Mercy Hospital | |
Kansas City, Missouri, United States, 64111 | |
United States, New York | |
Naomi Berrie Diabetes Center at Columbia University | |
New York, New York, United States, 10032 | |
SUNY Upstate Medical University | |
Syracuse, New York, United States, 13210 | |
United States, North Carolina | |
University of North Carolina | |
Chapel Hill, North Carolina, United States, 27713 | |
United States, Pennsylvania | |
Children's Hospital of Philadelphia | |
Philadelphia, Pennsylvania, United States, 19104 | |
United States, Tennessee | |
Vanderbilt University | |
Nashville, Tennessee, United States, 37212 | |
United States, Texas | |
Baylor College of Medicine | |
Houston, Texas, United States, 77030 |
Responsible Party: | Jaeb Center for Health Research |
ClinicalTrials.gov Identifier: | NCT03263494 |
Other Study ID Numbers: |
CITY |
First Posted: | August 28, 2017 Key Record Dates |
Last Update Posted: | March 3, 2020 |
Last Verified: | March 2020 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | Yes |
Product Manufactured in and Exported from the U.S.: | Yes |
Diabetes Mellitus Diabetes Mellitus, Type 1 Glucose Metabolism Disorders Metabolic Diseases |
Endocrine System Diseases Autoimmune Diseases Immune System Diseases |