Continuous Glucose Monitoring (CGM) Substudy of the DECIDE RCT
NCT Number: NCT06490874
Acronym: DECIDE CGM
Status: NOT_YET_RECRUITING
Study Type: OBSERVATIONAL
Conditions: Gestational Diabetes Mellitus|Pregnancy, High Risk
Interventions: DEVICE: CGM device - Metformin group|DEVICE: CGM device - Insulin group
Sponsor: Ohio State University
Collaborators: The George Washington University Biostatistics Center|DexCom, Inc.
Sex: FEMALE
Age: ADULT, OLDER_ADULT
Enrollment: 300
Study Design: Observational Model: |Time Perspective: p
Start Date: 2024-09
Completion Date: 2030-12
Locations: University of Alabama, Tuscaloosa, Alabama, 35487, United States|Massachusetts General Hospital, Boston, Massachusetts, 02114, United States|University of New Mexico, Albuquerque, New Mexico, 87131, United States|University of North Carolina Chapel Hill, Chapel Hill, North Carolina, 27514, United States|The Ohio State University Wexner Medical Center OB/GYN Maternal and Fetal Medicine, Columbus, Ohio, 43210, United States|Premier Health - Miami Valley Hospital, Dayton, Ohio, 45409, United States

Summary:
This is a nested multicenter prospective cohort conducted concurrently and in conjunction with the DECIDE two-arm, pragmatic non-inferiority comparative effectiveness Randomized Controlled Trial (RCT) (NCT06445946) of metformin versus insulin among individuals with Gestational diabetes mellitus (GDM) requiring pharmacotherapy for glycemic control. Continuous Glucose Monitoring (CGM)-derived glycemic metric in pregnancy and postpartum will be compared between individuals randomized to metformin versus insulin. In addition, the association between CGM metrics and adverse pregnancy outcomes will be examined. Finally, whether CGM metrics can accurately identify diabetes postpartum compared with an oral glucose tolerance test and hemoglobin A1c will be determined. A total of 300 (150 metformin, 150 insulin) pregnant individuals will be recruited with GDM who require pharmacotherapy to use a blinded CGM device (Dexcom, Inc, San Diego, CA) at two pregnancy (medication randomization, late third trimester) and three postpartum timepoints (delivery, \~6 weeks, and \~2 years).

Primary Outcome Measures: Time in range (TIR), Percent of time CGM readings are within the pregnancy target glucose range of 63 to 140 mg/dL. This outcome will be assessed as a continuous measure in increments of 1%., From medication randomization till late third trimester, up to 14 weeks
Secondary Outcome Measures: Coefficient of variation (CV), Percent of glycemic variability calculated as the standard deviation (SD) of glucose values divided by the mean glucose in the same observation period, continuous measure, From medication randomization till 2 years postpartum, up to 40 months.|Time below range (TBR), Percent of CGM readings and time below the target glucose range of \<63 mg/dL, continuous measure, From medication randomization till 2 years postpartum, up to 40 months.|Time above range (TAR), Percent of CGM readings and time above the target glucose range of \>140 mg/dL, continuous measure, From medication randomization till 2 years postpartum, up to 40 months.|Large-for-gestational-age at birth, LGA will be defined as a birthweight ≥90th%tile for gestational age based on a US birth certificate reference adjusted for parity and/or fetal sex., At delivery|Hypoglycemia, Neonatal hypoglycemia will be defined as a blood glucose \<35 mg/dL or treatment \<24 hours after birth with either IV, PO, or gel glucose therapy., <24 hours after birth|Hyperbilirubinemia, Neonatal hyperbilirubinemia will be defined as treated with phototherapy or exchange transfusion in the first postnatal week and either treatment in the first postnatal week or kernicterus., Within one week after birth|Hypertensive disorder of pregnancy, HDP will include either gestational hypertension or preeclampsia. Gestational hypertension will be defined as: systolic blood pressure of 140 mm Hg or more or diastolic blood pressure of 90 mm Hg or more on two occasions at least 4 hours apart after 20 weeks of gestation in a woman with a previously normal blood pressure. Preeclampsia will be defined as: above blood pressure criteria AND proteinuria (300 mg or more per 24 hour urine collection, protein/creatinine ratio of 0.3 mg/dL or more, or dipstick reading of 2+) OR thrombocytopenia (platelet count less than 100 109/L), renal insufficiency (serum creatinine greater than 1.1 mg/dL or a doubling of the serum creatinine concentration in the absence of other renal disease), impaired liver function (elevated blood concentrations of liver transaminases to twice normal concentration), pulmonary edema, new-onset headache or visual symptoms not attributed to other diagnoses., Randomization to delivery|Preterm birth, Preterm birth \<37 weeks and \<34 weeks based on project gestational age., At birth|Requiring mechanical ventilation, Intubation, continuous positive airway pressure (CPAP) or high-flow nasal cannula (HFNC) for ventilation or cardiopulmonary resuscitation within first 72 hours of birth., <72 hours after birth|NICU admission, Admitted to NICU or intermediate nursery ≥72 hours, any indication., Birth to infant date of delivery discharge (length of NICU admission will vary for each infant )|Oxygen support, Requiring oxygen support., <72 hours after birth|Respiratory distress syndrome, Signs of respiratory distress with oxygen requirement and confirmed by chest x-ray., Anytime during the first 72 hours after birth|Treatment supplementation, Insulin use among individuals randomized to metformin between randomization and delivery., From randomization to delivery|Type 2 diabetes (T2D), A1c \> 6.5% OR fasting plasma glucose \> 126 mg/dL OR OGTT \> 200 mg/dL OR prior diagnosis per patient report., From delivery to 2 years postpartum|Prediabetes, A1c 5.7% to 6.4% OR fasting plasma glucose 100 mg/dl to 125 mg/dL OR OGTT 140 to 199 mg/dL., From delivery to 2 years postpartum|Impaired glucose tolerance (IGT), OGTT 2-hour value of 140 to 199 mg/dL32, From delivery to 2 years postpartum|Impaired fasting glucose (IFG), OGTT value of 100 to 125 mg/dL., From delivery to 2 years postpartum.|Obesity overall and by class, Weight and height will be combined to report BMI in kg/m\^2. BMI per the following classifications will be assessed: Normal or underweight: \< 25 kg/m2; Overweight: 25 to \< 30 kg/m2; Class 1: 30 to \< 35 kg/m2; Class 2: 35 to \< 40 kg/m2; and Class 3: 40 kg/m2 or greater., 2 years postpartum|Hypertension, Per American Heart Association criteria as below and/or antihypertensive medication or prior diagnosis per patient report, and defined as: Elevated: Systolic between 120-129 and diastolic less than 80 mm Hg; Stage 1: Systolic between 130-139 or diastolic between 80-89 mm Hg; and Stage 2: Systolic at least 140 or diastolic at least 90 mm Hg., 2 years postpartum|Cholesterol, Fasting state, defined as a continuous measure and dichotomous at the following thresholds for each component: Total cholesterol: \> 200 mg/dL; LDL cholesterol: \> mg/dL; HDL cholesterol: \< 40 mg/dL; Triglycerides: \> 200 mg/dL., 2 years postpartum|Mean glucose, Mean glucose in mg/dL per CGM readings, continuous measure, From medication randomization till 2 years postpartum, up to 40 months.