The Effectiveness of Rt-CGM to Improve Glycemic Control and Pregnancy Outcome in Patients With GDM
The Effectiveness of Rt-CGM to Improve Glycemic Control and Pregnancy Outcome in Patients With GDM
Real-time continuous glucose monitoring (CGM) systems provide users with information about
 current glucose levels and alert the patient before the upper or lower glucose threshold is
 reached or when glucose levels change rapidly. Hence, glycaemic excursions can be early
 identified and accordingly adapted by behavioural change or pharmacologic intervention.
 Randomized controlled studies adequately powered to evaluate the impact of long-term
 application of real-time CGM systems on the risk reduction of adverse obstetric outcomes are
 missing.
Intervention: Device description The Dexcom G6 intended use is for the management of diabetes
 in persons aged 2 years and older. The Dexcom G6 System is intended to replace fingerstick
 blood glucose testing for diabetes treatment decisions. Interpretation of the Dexcom G6
 System results should be based on the glucose trends and several sequential readings over
 time. The Dexcom G6 System also aids in the detection of episodes of hyperglycemia and
 hypoglycemia, facilitating both acute and long-term therapy adjustments. The Dexcom G6 System
 can be used alone or in conjunction with these digitally connected medical devices for the
 purpose of managing diabetes. The system consists of a sensor, transmitter, receiver, and
 mobile app. The sensor is a small, flexible wire inserted into subcutaneous tissue where it
 converts glucose into electrical current. The sensor incorporates an interferent layer that
 minimizes the effect of potential electroactive interferents, such as acetaminophen, by
 preventing it from reaching the sensor wire surface. The benefit of this interferent layer in
 blocking the effects of acetaminophen prevents falsely high glucose readings. Thus, users may
 ingest acetaminophen while wearing the G6 CGM system. The transmitter, which is connected to
 the sensor and worn on the body, samples the electrical current produced by the sensor and
 converts the measurement into a glucose reading using an onboard algorithm. The receiver
 and/or the app displays the glucose reading along with a rate of change arrow and a trend
 graph. Additionally, the receiver and/or app issues alarms and alerts to notify the patient
 of glucose level changes and other important system conditions. The app provides the
 additional capability to share data with "followers" using the Dexcom Share service. The
 receiver can be put into a blinded mode using CLARITY® software. In this mode, users are
 unable to see the CGM data or receive CGM alerts.

 CGM Ancillary Devices Dexcom CLARITY® is an accessory to users of the Dexcom CGM system. It
 is a software program that allows the transfer of glucose data from the CGM system to Dexcom
 remote servers for data management to allow use of the CGM data by the user and study
 clinicians. Target ranges of 60 to 140 mg/dl [3.3 to 7.8 mmol/l] will be set and the patients
 will be introduced in the use of alarm settings. Both participants and study sites will use
 CLARITY® to transfer glucose data between user and study site, whether CGM is used in blinded
 or real-time mode. A CLARITY® mobile app can be used for retrospective review of glucose data
 on the smart device and can also be set up to allow receipt of push notifications of CGM data
 facilitating weekly data review. For all patients (intervention and control group) an
 anonymized CLARITY® account will be created by using a sequential study number which is
 allocated at randomization (sex will be female and birth date for each account will be set to
 1.1.1990 for all accounts).

 1. For participants that have a supported phone, the G6 CGM app will be installed on
 participant's smart phone.

 2. An anonymized CLARITY® mobile account will be set up and linked to the research site.

 3. Participants will use CGM data for their diabetes management.

 5. A high alert threshold will be set at 140 mg/dl [7.8 mmol/l]. Low alert threshold and
 urgent low soon alerts will be turned off. If participants require insulin, the low alert
 will be turned on and the threshold set at 65 mg/dl [3.6 mmol/l]. In addition, the urgent low
 alert (55 mg/dl [3.1 mmol/l]), the urgent low soon alert (when glucose levels are falling
 fast and will be below 55 mg/dl [3.1 mmol/l] in less than 20 min) as well as alerts for rise
 and fall rate (3 mg/dl [0.17 mmol/l]) in addition to alerts for signal loss and no readings
 for more than 20 min will be enabled. 6. Participants with applicable smart phones may have
 CLARITY® push notifications on the CLARITY® mobile app about weekly time in range comparison
 enabled during the study.

 7. For app users, the "Share and Follow" functionality will be discussed and encouraged (i.e.

 the study participants are able to invite followers to review their glucose levels).

 8. For participants using the receiver only, the receiver will be downloaded into the
 CLARITY® clinic account at each visit. 9. For participants using real-time CGM data summary
 will be downloaded for documentation at V3 and V4 (between 36+0 and 38+6) as well as after
 delivery (VPP1) 10. The research team will review the CGM in CLARITY® to inform lifestyle and
 therapy recommendations. 11. The Dexcom G6 system will not be calibrated during the study
 period.
Inclusion Criteria:

 -  female patients between 18 and 55 years

 -  gestational diabetes mellitus in accordance with the IADPSG criteria between 24 and
 31+6 weeks of gestation by a 2h 75g OGTT

 Exclusion Criteria:

 -  Overt diabetes (i.e. pregestationally known type 1 or type 2 diabetes or fasting
 plasma glucose during the OGTT ≥126 mg/dl [7.0 mmol/l] or HbA1c ≥6.5% [44 mmol/l] or
 2h post-load OGTT levels ≥200 mg/dl [11.1 mmol/l] assessed before 24+0 weeks of
 gestation

 -  history of bariatric surgery or other surgeries that induce malabsorption

 -  long-term use (>2 weeks) of systemic steroids prior to enrolment

 -  multiple pregnancy

 -  Patients already using glucose lowering medications (metformin or insulin) before
 study entry

 -  fetal growth restriction due to placental dysfunction at study entry - Inpatient
 psychiatric treatment up to 1 year before enrolment

 -  Participation in this study in previous pregnancy