Adjusting Insulin Delivery to Activity

Not Applicable

Completed

Conditions: Diabetes
Nocturnal Hypoglycemia

Interventions: Device: Dexcom G4 Platinum CGM
Device: Activity monitor

Registration Number: NCT02299479

Lead Sponsor: Boston Children's Hospital

Brief Summary: Increased daytime activity in children and adolescents with type I diabetes is known to be associated with overnight hypoglycemia. We therefore wish to perform a prospective clinical study to assess the feasibility of using activity monitor data to adjust insulin pump basal rates and see whether we can help prevent overnight hypoglycemia or decrease related interventions following high activity days. We plan to carry this out by enrolling 20 subjects (10 subjects 1 to \<7 years old and 10 subjects 7 to 17 years old) with type 1 diabetes managed on insulin pump therapy and having them wear activity monitors and CGMs for up to 3 months. After an initial two-week period to establish activity baselines, we will recommend nighttime basal insulin rate adjustments based on activity monitor, CGM and insulin pump data.

Detailed Description: This study is a pilot trial investigating the feasibility of using activity monitoring data to adjust insulin pump therapy and prevent hypoglycemia. The study will enroll 20 patients with type 1 diabetes mellitus on insulin pump therapy, 10 from each of two age groups: younger children aged 1 year to \<7 years of age, and older children aged 7-17 years of age. Subjects will be provided with continuous glucose monitors (DexCom G4) and activity monitors. Study duration will be up to 3 months. During the course of the study patients will continue to receive routine care by their primary endocrinologist and diabetes nurse educator (DNE). Insulin dose adjustments unrelated to activity monitor data will continue to be at the discretion of the patient's primary diabetes team.

Activity level (steps and calories burned) will be uploaded over the web in a secure fashion to our central firewall-protected database on a daily basis while CGM glucose values and insulin pump data will be collected once a week. The initial 2 weeks of a subject's enrollment in the study will be used to establish his or her baseline activity level and no changes to the insulin regimen will be made based on the activity monitor data. During weeks 3 to 12, activity data will be reviewed daily and an alternate basal insulin rate will be recommended on days considered to be increased activity days. We will use an adaptive algorithm to help guide suggested insulin basal rate changes. All recommendations will be reviewed and approved by a physician prior to implementation. The alternate rate will be derived using the subject's usual care pump settings as an initial starting point from which to make incremental changes in the 3 hour interval leading up to the hypoglycemic event. Target will be the overnight nadir obtained with usual care settings. Residual error (CGM-target) will be used to assess the validity of using the 3 hour window prior to the event to effect lower basal.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 20

Inclusion Criteria

Type 1 diabetes (as clinically diagnosed by outpatient endocrinologist).
Treated with insulin pump therapy for greater than or equal 6 months
HbA1C of <8.5% in the previous 3 months
Families will need to have access to Wi-Fi and a compatible smartphone in order for the data from the activity monitor and other devices to be transmitted to the research team

Exclusion Criteria

• Current oral steroid use or other medication known to affect insulin action at investigator's discretion.

***Note: currently only enrolling patients followed at Boston Children's Hospital

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Intervention	Dexcom G4 Platinum CGM	Volunteers will wear a Dexcom G4 Platinum CGM device as well as an activity monitor. Data will be uploaded to study investigators on a regular basis, and recommendations will be made to adjust insulin dosing based upon analysis of these data.
Intervention	Activity monitor	Volunteers will wear a Dexcom G4 Platinum CGM device as well as an activity monitor. Data will be uploaded to study investigators on a regular basis, and recommendations will be made to adjust insulin dosing based upon analysis of these data.

Primary Outcome Measures

Name	Time	Method
Change From Baseline in Supplemental Carbohydrate Interventions up to 3 Months From Baseline.	Up to 3 months	Median and inter-quartile range (IQR) of supplemental carbohydrate (SC) interventions (number of SC given by parent divided by the number of days the SC were given) to prevent hypoglycemia during the study period will be compared to those given during the baseline period for each subject. The median and IQR of all subjects will then be calculated.

Secondary Outcome Measures

Name	Time	Method
Correlation of Daytime Activity With Nighttime Nadir Glucose.	Up to 3 months	Daytime activity will be determined based on steps and calories burned measured by activity monitor. High activity is defined as activity level more than 2 standard deviations above the subject's baseline. Correlations will be performed to assess if there is relationship between daytime activity (8 am to 9 pm) and nighttime nadir blood glucose level (mg/dL).
Change From Baseline in Supplemental Carbohydrate Interventions up to 3 Months From Baseline in Subjects With Activity Effect.	Up to 3 months	For subjects with an activity effect (subjects with a correlation between daytime activity and nighttime nadir glucose), median and inter-quartile range (IQR) of supplemental carbohydrate (SC) interventions (number of SC given by parent divided by the number of nights the SC were given) to prevent hypoglycemia during the study period will be compared to those given during the baseline period for each subject. The median and IQR of this subset of subjects will then be calculated.