Continuous Glucose Monitoring (CGM) Substudy of the DECIDE RCT

NCT06490874 | Withdrawn FDA Device

• 1 other identifier: 2024H0267
• Study Type: observational
• Target: N/A
• Locations: 1 country
• Sites: 4

Brief 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).

Conditions

Gestational Diabetes Mellitus; Pregnancy, High Risk

Keywords

Insulin; Pregnancy; Glycemic control; Metformin; Gestational diabetes; Diabetes; Adverse pregnancy outcomes; Continuous glucose monitoring

Outcome Measures

Primary Outcomes (1)

• 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 Outcomes (21)

• Coefficient of variation (CV)

  From medication randomization till 2 years postpartum, up to 40 months.

• Time below range (TBR)

  From medication randomization till 2 years postpartum, up to 40 months.

• Time above range (TAR)

  From medication randomization till 2 years postpartum, up to 40 months.

• Large-for-gestational-age at birth

  At delivery

• Hypoglycemia

  <24 hours after birth

Study Arms (2)

CGM device - Metformin

Individuals will be provided with a CGM device (Dexcom, Inc, San Diego, CA) to be worn for up to 10 days (minimum \>5 days) at two pregnancy (randomization to metformin or insulin, late third trimester \> 340/7 weeks) and three postpartum timepoints (immediately after delivery, \~6 weeks, and \~2 years). The CGM device will be used in blinded mode for both participants and providers (i.e., neither will be able to see glucose values).

Device: CGM device - Metformin group

CGM device - Insulin

Individuals will be provided with a CGM device (Dexcom, Inc, San Diego, CA) to be worn for up to 10 days (minimum \>5 days) at two pregnancy (randomization to metformin or insulin, late third trimester \> 340/7 weeks) and three postpartum timepoints (immediately after delivery, \~6 weeks, and \~2 years). The CGM device will be used in blinded mode for both participants and providers (i.e., neither will be able to see glucose values).

Device: CGM device - Insulin group

Interventions

CGM device - Metformin group DEVICE

Individuals randomized to metformin will be provided with a CGM device (Dexcom, Inc, San Diego, CA) to be worn for up to 10 days (minimum \>5 days) at two pregnancy (randomization to metformin or insulin, late third trimester \> 340/7 weeks) and three postpartum timepoints (immediately after delivery, \~6 weeks, and \~2 years).

CGM device - Metformin

CGM device - Insulin group DEVICE

Individuals randomized to insulin will be provided with a CGM device (Dexcom, Inc, San Diego, CA) to be worn for up to 10 days (minimum \>5 days) at two pregnancy (randomization to metformin or insulin, late third trimester \> 340/7 weeks) and three postpartum timepoints (immediately after delivery, \~6 weeks, and \~2 years).

CGM device - Insulin

Eligibility Criteria

• Age: 18 Years+
• Gender Eligibility Details: This study is restricted to pregnant individuals with GDM.
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

A subset of 300 individuals (150 metformin, 150 insulin) will be consecutively enrolled in participating sites to this substudy from the 1,572 individuals from the parent DECIDE trial (NCT06445946).

You may qualify if:

• Singleton gestation. Twin reduction to singleton, either spontaneously or therapeutically, is eligible if it occurred before 14 weeks gestational age.
• Age \>18 years
• Gestational age at randomization between 200/7 - 316/7 weeks based on project gestational age.
• GDM diagnosis between 200/7 - 316/7 weeks based on project gestational age.
• Requires medication for glucose control defined as ≥30% elevated glucose values (either fasting or postprandial or both) in the week prior to randomization per determination of the provider or documented in the medical record.
• Patient willingness and ability to attend 2-year follow-up visit.
• Patient willingness to wear and return a blinded CGM device. It is possible that some enrolled individuals may choose to use a separate CGM device for glucose monitoring as part of clinical care.

You may not qualify if:

• Renal disease (serum creatinine \>1.3 mg/dL) due to the potential impact of metformin on renal function.
• Major structural malformation of the fetus.
• Known fetal aneuploidy based on invasive testing or positive for aneuploidy on cell-free fetal DNA screening.
• Contraindication to metformin or insulin, including: history of lactic acidosis, intractable nausea and vomiting, prior documented allergy and/or anaphylaxis.
• Pregestational diabetes documented in the medical record, GDM diagnosis \<20 weeks, or prior A1c\>6.5%
• Fasting hyperglycemia \>115 mg/dl for ≥50% of fasting glucose values in the past week (due to the high risk of metformin failure with fasting hyperglycemia).
• Enrolled in a trial that influences primary study outcomes of the parent DECIDE trial (composite neonatal outcome at delivery or childhood body mass index at 2 years).
• Prenatal care or delivery planned at a location where access to the complete electronic medical record will not be available to research staff.
• Language barrier (appropriate translation resources unavailable at the site).
• Participation in this trial in a previous pregnancy. Patients who were screened in a previous pregnancy, but not randomized, may be included.
• In addition, individuals who report a prior allergy or sensitivity to CGM will also be excluded.

Sponsors & Collaborators

• Ohio State University: lead
• The George Washington University Biostatistics Center: collaborator
• DexCom, Inc.: collaborator

Study Sites (4)

University of Alabama

Tuscaloosa, Alabama, 35487, United States

Location

Massachusetts General Hospital

Boston, Massachusetts, 02114, United States

Location

The Ohio State University Wexner Medical Center OB/GYN Maternal and Fetal Medicine

Columbus, Ohio, 43210, United States

Location

Premier Health - Miami Valley Hospital

Dayton, Ohio, 45409, United States

Location

MeSH Terms

Conditions

Diabetes, Gestational; Insulin Resistance; Diabetes Mellitus

Condition Hierarchy (Ancestors)

Pregnancy Complications; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases; Hyperinsulinism

Study Officials

• Kartik Venkatesh, MD, PhD

  Ohio State University

  PRINCIPAL INVESTIGATOR

• Donna Gregory, RNC, BSN

  Ohio State University

  STUDY DIRECTOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: June 17, 2024
• First Posted: July 8, 2024
• Study Start: September 1, 2025
• Primary Completion (Estimated): December 1, 2029
• Study Completion (Estimated): December 1, 2030
• Last Updated: October 28, 2025

Record last verified: 2025-10

Data Sharing

• IPD Sharing: Will not share

Locations

US (4)