Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT04142944 |
| Other study ID # |
19HH5053 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
December 11, 2019 |
| Est. completion date |
July 27, 2021 |
Study information
| Verified date |
November 2021 |
| Source |
Imperial College London |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Observational, within-subject, crossover study
To assess the impact of Dexcom G6 RT-CGM with a predictive hypoglycaemia alert function on
the frequency, duration and severity of hypoglycaemia occurring before, during and after
regular physical activity in people with type 1 diabetes
At Imperial College Healthcare NHS Trust have established the multi-disciplinary Imperial
Physical Activity and Diabetes (IPAD) clinic to empower, educate and enable people with
diabetes to manage their blood glucose when they undertake physical activity. The
investigator utilise the skills and expertise of a consultant diabetologist, a diabetes
dietitian, a consultant in sports & exercise medicine, and a diabetes specialist nurse with
expertise in diabetes technology. The investigator have access to diagnostic & therapeutic
radiology, physiotherapy and psychology services.
Description:
CLINIC VISIT 1: Screening
Following informed consent study participants will give a full medical and medication
history. Venous blood tests will be taken to assess HbA1c and renal function. C-peptide will
be measured in participants who have not had previous tests to confirm T1DM diagnosis.. Women
of childbearing age will have a urine pregnancy test. An ECG will be performed in
participants with longstanding Type 1 Diabetes Mellitus (>10 years) or participants who are
>40 years old.
CLINIC VISIT 2: Run-in
If participants meet the inclusion criteria they will be enrolled on to the study, within a
month of screening and at a time that is convenient to them. For the 10 days of the run-in
period, participants CGM will be blinded, meaning that they will be wearing the CGM sensor
but will not see any of the glucose data. They will wear a sensor which will be attached to a
transmitter which will send data to a Dexcom receiver. The receiver must be kept within 6
meters of the transmitter most of the time as the transmitter can only store three hours of
data. After the run in they will be able to use the Smartphone app instead of carrying the
receiver if they wish. They will be taught to insert the sensor at the run-in visit, and
provided with spares in case of sensor failure. Participants will be instructed to test their
capillary blood glucose levels and self-manage their type 1 diabetes as normal during the
run-in period. The run in phase will last 10 days.
Data on food intake, and insulin usage will be collected for the full duration of the study
using a smart phone app (mySugr) in those treated with insulin injections, or using the
built-in system in the pumps of those using insulin pump therapy. Both the app and the
insulin pumps allow participants to input their own insulin doses, or use the bolus
calculator which uses the participant's individual insulin:carbohydrate ratio to help
calculate insulin doses based on the carbohydrate intake. There will be no change in
participants' insulin dosing, and participants will make all their insulin dosing decisions
themselves, based on their pre-study insulin:carbohydrate ratios. The advantage of using the
app or bolus advisor is that the tracking of the insulin action (which lasts for 3-5 hours)
allows participants to see how much insulin is still active. This is important when the CGM
is unblinded as it can prevent participants giving additional insulin unnecessarily when they
see their blood glucose levels on the CGM. Those using insulin injections will be provided
with a smart insulin pen, a device similar to the participants' usual insulin delivery device
use, but with a memory capable of storing dosing data until the end of the study (Inpen,
produced by Companion Medical).
A structured education refresher focusing on carbohydrate counting, hypoglycaemia avoidance,
recognition, and management, insulin action and the theory and practicalities of CGM will be
provided. All education will be delivered by the research dietitian with a checklist of
topics that are provided as part of routine care.
Participants will wear a GPS-enabled sports watch with built-in heart rate monitor (Garmin
Forerunner 935) for the entire duration of the study. Participants will be asked to download
the Garmin Connect App for data from the Garmin watch to be transmitted to the app via
Bluetooth. They will be provided with anonymised log in details for the app and a charger for
the watch. Volunteers will be asked to record their activity type and perceived physical
exertion after every session of exercise.
Quality of life data will be collected by mixed quantitative and qualitative methodologies.
Validated questionnaires (HFS-II, Gold, RPAQ, DDS17) will be used to assess fear of
hypoglycaemia, hypoglycaemia awareness, recent physical activity and diabetes distress. The
investigator will undertake a short interview about the participants perceptions and
experience of CGM.
CLINIC VISIT 3: Randomisation
Ten days after visit 2, participants will attend the research clinic for the randomisation
appointment. The CGM, Garmin data and insulin bolus data (from mysugr or insulin pump) will
be downloaded. Participants will have their weight and body composition measured using
electrical impedance scales. Participants will start using their CGM unblinded, so that they
are able to view their glucose levels either on the receiver or on the Dexcom app on their
smartphones, depending on choice. Participants will be randomised to real-time continuous
glucose monitoring with Predictive Hypoglycaemia Alert Algorithm enabled (ON group) or
real-time continuous glucose monitoring with Predictive Hypoglycaemia Alert Algorithm
disabled (OFF group). Randomisation will be done using sealedenvelope.com and stratified by
insulin delivery modality and previous CGM experience. Participants will be provided with
sensors for the rest of the study.
Participants will be instructed to test their capillary blood glucose if symptoms of hypo- or
hyperglycaemia occur, in case of sensor failure or if the sensor glucose is out of the
desired range, in line with the device license. Participants will change sensor every ten
days (or sooner in the event of sensor failure). Low glucose alert settings will be
standardised at 4.4 mmol/L (80mg/dL) for all participants at the start of the study and can
be reduced to 4 mmol/L (70mg/dL) at week 2 during the telephone visit depending on
participant preference. High glucose alerts may be personalised. Participants will be
provided with a contact number for technical support but insulin titration decisions will be
made by the participant.
Two weeks after visit 3 and 4, all participants will receive a telephone call from the
research dietitian to discuss any queries they have regarding the CGM, sports watch or any
other element of the study. Those in the ON group will also be able to adjust the predictive
hypoglycaemia alert level from 4.4 mmol/L (80mg/dL) to 4 mmol/L (70mg/dL) if preferred.
Each study period will last 40 days.
CLINIC VISIT 4: Cross-over
Forty days after visit 3, participants will attend the research clinic and be switched onto
the opposite intervention (ON/OFF) for the second phase of the study, which will last 40
days. Participants will continue to use the mySugr app or bolus advisor on their pumps, the
Garmin watch and inpen or pump. The CGM, Garmin data and bolus data from mysugr will all be
downloaded.
The questionnaires assessing fear of hypoglycaemia, hypoglycaemia awareness, recent physical
activity and diabetes distress will be repeated, as well as a short CGM interview on
perceptions and experience of CGM.
VISIT 5: End of study
Forty days after visit 4, and 90 days after the start of the study, the study will end. All
participants will be reviewed by the research dietitian at the research clinic for data to be
collected and uploaded and to address any issues arising from the study. Smart insulin pens,
G6 CGM and garmin watches will be returned and downloaded. Insulin pumps, mysugr apps and
blood glucose meters will also be downloaded.
CSV files will be downloaded from mySugr. There is no patient identifiable information in the
CSV file. Garmin data is sent from phone to the Garmin connect app via Bluetooth, without any
identifiable information, and CSV files can be downloaded from Garmin connect with a secure
login. There is no patient data on the inpen, which will be downloaded onto Imperial College
London computers, and will be associated with the anonymous email containing the study ID
number for each participant. Insulin pumps and blood glucose meters will be downloaded onto
NHS computers.
HbA1c will be rechecked at this point via venous blood tests. Weight and body composition
measurements will also be repeated.
Validated questionnaires to assess fear of hypoglycaemia, hypoglycaemia awareness, recent
physical activity and diabetes distress, will be repeated. A short interview about the
participants perceptions and experience of CGM will be undertaken.
