CGM Intervention in Teens and Young Adults With Type 1 Diabetes (T1D) (CITY)

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

Adolescents and young adults with T1D and poor glycemic control (age 14-< 25 years, T1D duration >12 months, HbA1c 7.5-<11.0%, using an insulin pump or MDI)) will be randomly assigned to either CGM or BGM. Sample size will be 150. The primary outcome assessment will be HbA1c after 6 months. Secondary outcomes will include HbA1c, CGM metrics (control group will wear blinded CGM at 13 and 24 weeks), and quality of life measures. The randomized trial will be followed by a 6-month extension study during which the RCT control group will initiate CGM and the RCT CGM group will continue CGM.

Study Overview

• Status: Completed
• Conditions: Type 1 Diabetes Mellitus
• Intervention / Treatment: Device: Continuous Glucose Monitor (CGM)

• Study Type: Interventional
• Enrollment (Actual): 153
• Phase: Phase 3

Contacts and Locations

Study Locations

• United States
  • California
    • Los Angeles, California, United States, 90027
      • Children's Hospital Los Angeles
    • Palo Alto, California, United States, 94304
      • Stanford University
  • Colorado
    • Aurora, Colorado, United States, 80045
      • Barbara Davis Center--University of Colorado
  • Connecticut
    • New Haven, Connecticut, United States, 06511
      • Yale University
  • Idaho
    • Idaho Falls, Idaho, United States, 83404
      • Rocky Mountain Diabetes & Osteoporosis Center
  • Massachusetts
    • Boston, Massachusetts, United States, 02215
      • Joslin Diabetes Center
  • Minnesota
    • Saint Louis Park, Minnesota, United States, 55416
      • IDC at Park Nicollet
  • Missouri
    • Kansas City, Missouri, United States, 64111
      • Children's Mercy Hospital
  • New York
    • New York, New York, United States, 10032
      • Naomi Berrie Diabetes Center at Columbia University
    • Syracuse, New York, United States, 13210
      • SUNY Upstate Medical University
  • North Carolina
    • Chapel Hill, North Carolina, United States, 27713
      • University of North Carolina
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19104
      • Children's Hospital of Philadelphia
  • Tennessee
    • Nashville, Tennessee, United States, 37212
      • Vanderbilt University
  • Texas
    • Houston, Texas, United States, 77030
      • Baylor College of Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years to 24 years (Child, Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. 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
2. Age 14-<25 years
3. Diabetes duration ≥ 1 year
4. Total daily insulin requirement ≥ 0.4 units/kg/day
5. HbA1c 7.5% to <11.0% (Point of care device or local lab measured as part of study at screening visit)
6. 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
7. 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
8. 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.
9. Participant comprehends written and spoken English
10. Participant understands the study protocol and agrees to it (if applicable)

Exclusion Criteria:

1. 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
2. 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
3. Started on non-insulin medication for blood glucose control within the past 3 months or plans to begin within the next 6 months
4. 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.
5. More than 1 episode of DKA in the past 6 months as defined in the adverse events chapter.

6. 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)
7. Inpatient psychiatric treatment in the past 6 months or daily intensive outpatient psychiatric day treatment in the past 3 months.
8. Pregnant (positive test confirmed at screening) or planning to become pregnant in the next 12 months.
9. Need for use of acetaminophen or acetaminophen-containing products on a regular basis during the 6 months of the trial
10. Participation in a diabetes related intervention study in the past 6 weeks.
11. Any medical, psychological or social situation where per investigator discretion it may be difficult for participant to participate fully in the intervention
12. 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / 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

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change in HbA1c from baseline to 26 weeks adjusted for baseline	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
% with HbA1c <7.0%		6 months
% with HbA1c <7.5%		6 months
% with relative reduction ≥ 10%		6 months
% with absolute reduction ≥ 0.5%		6 months
% with absolute reduction ≥ 1%		6 months
% with absolute reduction ≥ 1% or HbA1c < 7.0%		6 months
CGM % time in range 70-180 mg/dl		6 months
CGM mean glucose		6 months
CGM glucose variability measured by coefficient of variation		6 months
CGM % time > 180 mg/dl		6 months
CGM % time > 300 mg/dl		6 months
CGM % time < 54 mg/dl		6 months
CGM % time < 70 mg/dl		6 months
Rate of CGM measured hypoglycemic episodes (using <54 mg/dL)		6 months
CGM Self Efficacy Questionnaire Score	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.	6 months
Problem Areas in Diabetes (PAID) Questionnaire Score	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.	6 months
Glucose Monitoring Satisfaction Questionnaire Score	Survey containing 15 questions. Total score ranges from 0-100. A higher total score indicates more satisfaction with their current glucose monitor.	6 months
Hypoglycemia Confidence Questionnaire Score	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.	6 months
Diabetes Technology Attitudes Questionnaire Score	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.	6 months
Pittsburgh Sleep Quality Index	Survey containing 19 questions. Total score ranges from 0-21. A lower score indicates a healthier sleep quality.	6 months

Collaborators and Investigators

• Sponsor: Jaeb Center for Health Research
• Collaborators: The Leona M. and Harry B. Helmsley Charitable Trust

Publications and helpful links

General Publications

• Laffel LM, Kanapka LG, Beck RW, Bergamo K, Clements MA, Criego A, DeSalvo DJ, Goland R, Hood K, Liljenquist D, Messer LH, Monzavi R, Mouse TJ, Prahalad P, Sherr J, Simmons JH, Wadwa RP, Weinstock RS, Willi SM, Miller KM; CGM Intervention in Teens and Young Adults with T1D (CITY) Study Group; CDE10. Effect of Continuous Glucose Monitoring on Glycemic Control in Adolescents and Young Adults With Type 1 Diabetes: A Randomized Clinical Trial. JAMA. 2020 Jun 16;323(23):2388-2396. doi: 10.1001/jama.2020.6940.

Study record dates

Study Major Dates

• Study Start (Actual): January 25, 2018
• Primary Completion (Actual): May 8, 2019
• Study Completion (Actual): November 7, 2019

Study Registration Dates

• First Submitted: August 24, 2017
• First Submitted That Met QC Criteria: August 24, 2017
• First Posted (Actual): August 28, 2017

Study Record Updates

• Last Update Posted (Actual): March 3, 2020
• Last Update Submitted That Met QC Criteria: March 2, 2020
• Last Verified: March 1, 2020

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Immune System Diseases; Autoimmune Diseases; Endocrine System Diseases; Diabetes Mellitus; Diabetes Mellitus, Type 1
• Other Study ID Numbers: CITY

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• 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