Continuous Glucose Sensor Profiles in Non-Diabetic Subjects

Study Overview
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Brief Summary
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The Juvenile Diabetes Research Foundation (JDRF) Glucose Sensor Study group is carrying out a large, randomized clinical trial to assess the efficacy, safety and cost-effectiveness of use of real-time continuous glucose monitors (RT-CGM) as an adjunct to standard meter plasma glucose testing. Although the primary outcome in the >= 7.0% cohort is differences in HbA1c levels, important secondary outcomes are differences in the percent of glucose sensor values either above or below the target glucose range of 70-180 mg/dl and differences in glucose variability. Prevention of biochemical hypoglycemia is a particularly important outcome in the low HbA1c cohort. Since CGM systems measure interstitial rather than plasma glucose and CGM values differ from simultaneous plasma glucose values by up to 18%, it would be extremely useful for comparative purposes to establish a reference range of sensor values in healthy, non-diabetic control subjects for this study and other future investigations. The objective of this protocol is to establish such reference sensor glucose ranges in each of the 3 devices being utilized in the JDRF study.

Detailed Description
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After initial eligibility is determined, informed consent and assent are obtained from the parent/guardian and subject. Subjects will have the following tests performed: Hemoglobin A1c (using the DCA2000 or equivalent device) Oral glucose tolerance test to obtain fasting and 2 hour plasma glucose levels Anti-GAD, anti-IA2 and anti-insulin antibodies Subjects with an HbA1c >6.0% and/or fasting glucose levels >100 and/or 2 hour glucose levels >140 will be discontinued from the study. Subjects with normal A1c and glucose levels will be provided with an RT-CGM and home glucose meter (HGM) An RT-CGM sensor will be inserted and initiated by study personnel. Subjects who would like to wear 2 sensors will be given 2 of the same type of RT-CGM. Subjects will be instructed to wear the sensor for 3-7 days (depending on the type of device) and measure the blood glucose on the HGM as needed to calibrate the sensor. Subjects will return to the clinical center after the 3-7 days of sensor wear to return the RT-CGM and HGM. If the subject has less than 48 hours of sensor data he or she will be asked to wear another sensor and return 3-7 days later.

Official Title
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A Study to Assess Continuous Glucose Sensor Profiles in Healthy Non-Diabetic Subjects

Conditions
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Healthy Subjects Without Type 1 Diabetes

Intervention / Treatment
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* Device: Continuous glucose monitor


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age > 8 years Body mass index (BMI) between the 10th to 90th percentile for age and sex (based on CDC, 2000 nomogram) and < 28 kg body weight/meter in adult subjects No significant chronic illness or taking any acute or chronic medications that might affect glucose metabolism. Exclusion Criteria: History of diabetes or positive islet cell antibody testing

Ages Eligible for Study
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Minimum Age: 8 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Intervention/Treatment |
| --- |
|Device: Continuous glucose monitor|Daily use of a continuous glucose monitor for 3-7 days|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall Mean Sensor Glucose by Age Group | Mean glucose value was calculated for every hour of the 24 hours of the day. This measure is the average over all 24 hours. | 48-72 hours | 
| Daytime (6:00 a.m. - Midnight) Mean Sensor Glucose by Age Group | Mean glucose value was calculated for every hour of the 24 hours of the day. This measure is the average from 6 a.m. to midnight. | 48-72 hours | 
| Nighttime (Midnight - 6:00 a.m.) Mean Sensor Glucose by Age Group | Mean glucose value was calculated for every hour of the 24 hours of the day. This measure is the average from midnight to 6 a.m. | 48-72 hours | 
| Peak Daytime Sensor Glucose Value by Age Group | The calculation of peak and nadir glucose was restricted to days with >=12 hours and nights with >=4 hours of sensor glucose data. | 48-72 hours | 
| Peak Nightime Sensor Glucose Value by Age Group | The calculation of peak and nadir glucose was restricted to days with >=12 hours and nights with >=4 hours of sensor glucose data. | 48-72 hours | 
| Daytime Nadir Sensor Glucose Value by Age Group | The calculation of peak and nadir glucose was restricted to days with >=12 hours and nights with >=4 hours of sensor glucose data. The daytime nadir reflects the lowest point on the sensor glucose curve registered among daytime values. | 48-72 hours | 
| Nighttime Nadir Sensor Glucose Value by Age Group | The calculation of peak and nadir glucose was restricted to days with >=12 hours and nights with >=4 hours of sensor glucose data. The nighttime nadir reflects the lowest point on the sensor glucose curve registered among nighttime values. | 48-72 hours | 
| Percentage of Sensor Glucose Levels Between 71-120 mg/dL by Age Group | The Percentage Sensor Glucose Levels between 71-120 mg/dL was calculated for each subject. The median and quartiles over all subjects were reported here. | 48-72 hours | 
| Percentage of Sensor Glucose Levels 71-120 mg/dL by Time of Day |  | 48-72 hours | 
| Distribution of Sensor Glucose Levels <=70 mg/dL by Age Group |  | 48-72 hours | 
| Percentage of Sensor Glucose Levels <=70 mg/dl by Time of Day |  | 48-72 hours | 
| Percentage of Sensor Glucose Levels <=60 mg/dL by Age Group |  | 48-72 hours | 
| Percentage of Sensor Glucose Levels <=60 mg/dl by Time of Day | The Percentage of Sensor Glucose Levels <=60 mg/dl was calculated for each subject separately for the daytime and nighttime period. The median and quartiles over all subjects were reported. Here the data is different with data analyzed by age group, which is a subgroup analysis on 'percentage of sensor glucose levels <=60mg/dL' for all 24 hours. | 48-72 hours | 
| Percentage of Sensor Glucose Levels >120 mg/dL by Age Group |  | 48-72 hours | 
| Percentage of Sensor Glucose Levels >120 mg/dl by Time of Day |  | 48-72 hours | 
| Percentage of Sensor Glucose Levels >140 mg/dL by Age Group |  | 48-72 hours | 
| Percentage of Sensor Glucose Levels >140 mg/dl by Time of Day | The Percentage of Sensor Glucose Levels >140 mg/dl was calculated for each subject separately for the daytime and nighttime period. The median and quartiles over all subjects were reported. Here the data is different with data analyzed by age group, which is a subgroup analysis on 'percentage of sensor glucose levels >140 mg/dl' for all 24 hours. | 48-72 hours | 
| Glucose Variability Measure- Standard Deviation by Age Group | Here, 'Standard Deviation' is a measure of glucose variability. This measure was calculated by taking the SD of all glucose values for each subject. Each subject has a SD value. The median and quartiles of this measure over all subjects were reported. | 48-72 hours | 
| Glucose Variability Measure- Standard Deviation by Time of Day | Here, 'Standard Deviation' is a measure of glucose variability. This measure was calculated by taking the SD of all glucose values for each subject. Each subject has a SD value. The median and quartiles of this measure over all subjects were reported. | 48-72 hours | 
| Glucose Variability Measure- Absolute Rate of Change by Age Group |  | 48-72 hours | 
| Glucose Variability Measure- Absolute Rate of Change by Time of Day |  | 48-72 hours | 
| Glucose Variability Measure- Coefficient of Variation by Age Group | The Coefficient of Variation is calculated by dividing the standard deviation by the mean glucose. Each subject received a SD value. The median and quartiles of this measure over all subjects were reported. | 48-72 hours | 
| Glucose Variability Measure- Coefficient of Variation by Time of Day | The Coefficient of Variation is calculated by dividing the standard deviation by the mean glucose. Each subject received a SD value. The median and quartiles of this measure over all subjects were reported. | 48-72 hours | 
| Glucose Variability Measure: Mean Amplitude of Glycemic Excursions by Age Group | The Mean Amplitude of Glycemic Excursions also known as MAGE depicts the upward and downward acute glucose fluctuations seen in the sensor data. | 48-72 hours | 
| Glucose Variability Measure: Amplitude of Glycemic Excursions by Time of Day | The Mean Amplitude of Glycemic Excursions also known as MAGE depicts the upward and downward acute glucose fluctuations seen in the sensor data. | 48-72 hours |