Intensive glycaemic targets in overweight and obese individuals with gestational diabetes mellitus: clinical trial protocol for the iGDM study.

INTRODUCTION: The prevalence of both obesity and gestational diabetes mellitus (GDM) has increased, and each is associated with adverse perinatal outcomes including fetal overgrowth, neonatal morbidity, hypertensive disorders of pregnancy and caesarean delivery. Women with GDM who are also overweight or obese have higher rates of pregnancy complications when compared with normal-weight women with GDM, which may occur in part due to suboptimal glycaemic control. The current recommendations for glycaemic targets in pregnant women with diabetes are based on limited evidence and exceed the mean fasting (70.9±7.8 mg/dL) and 1-hour postprandial (108.9±12.9 mg/dL) glucose values in pregnant individuals without diabetes. Our prior work demonstrated that the use of intensive (fasting <90 mg/dL and 1-hour postprandial <120 mg/dL) compared with standard (fasting <95 mg/dL and 1-hour postprandial <140 mg/dL) glycaemic targets resulted in improved glycaemic control without increasing the risk for hypoglycaemia in pregnant individuals with GDM, but the impact of intensive glycaemic targets on perinatal outcomes is unknown. METHODS AND ANALYSIS: The Intensive Glycemic Targets in Overweight and Obese Women with Gestational Diabetes Mellitus: A Multicenter Randomized Trial (iGDM Trial) is a large, pragmatic randomised clinical trial designed to investigate the impact of intensive versus standard glycaemic targets on perinatal outcomes in women with GDM who are overweight and obese. During the 5-year project period, a multidisciplinary team of investigators from five medical centres representing regions of the USA with high rates of obesity will randomise 828 overweight and obese women with GDM to either intensive or standard glycaemic targets. We will test the central hypothesis that intensive glycaemic targets will result in lower rates of neonatal composite morbidity including large for gestational age birth weight, neonatal hypoglycaemia, respiratory distress syndrome and need for phototherapy when compared with standard glycaemic targets using the intention-to-treat approach to analysis. ETHICS AND DISSEMINATION: The Institutional Review Board (IRB) at Indiana University School of Medicine approved this study (IRB# 11435; initial approval date 25 August 2021). We will submit the results of the trial for publication in peer-reviewed journals and presentations at international scientific meetings. TRIAL REGISTRATION NUMBER: NCT05124808.

Metformin Plus Insulin for Preexisting Diabetes or Gestational Diabetes in Early Pregnancy: The MOMPOD Randomized Clinical Trial.

Importance: Insulin is recommended for pregnant persons with preexisting type 2 diabetes or diabetes diagnosed early in pregnancy. The addition of metformin to insulin may improve neonatal outcomes. Objective: To estimate the effect of metformin added to insulin for preexisting type 2 or diabetes diagnosed early in pregnancy on a composite adverse neonatal outcome. Design, Setting, and Participants: This randomized clinical trial in 17 US centers enrolled pregnant adults aged 18 to 45 years with preexisting type 2 diabetes or diabetes diagnosed prior to 23 weeks' gestation between April 2019 and November 2021. Each participant was treated with insulin and was assigned to add either metformin or placebo. Follow-up was completed in May 2022. Intervention: Metformin 1000 mg or placebo orally twice per day from enrollment (11 weeks -<23 weeks) through delivery. Main Outcome and Measures: The primary outcome was a composite of neonatal complications including perinatal death, preterm birth, large or small for gestational age, and hyperbilirubinemia requiring phototherapy. Prespecified secondary outcomes included maternal hypoglycemia and neonatal fat mass at birth, and prespecified subgroup analyses by maternal body mass index less than 30 vs 30 or greater and those with preexisting vs diabetes early in pregnancy. Results: Of the 831 participants randomized, 794 took at least 1 dose of the study agent and were included in the primary analysis (397 in the placebo group and 397 in the metformin group). Participants' mean (SD) age was 32.9 (5.6) years; 234 (29%) were Black, and 412 (52%) were Hispanic. The composite adverse neonatal outcome occurred in 280 (71%) of the metformin group and in 292 (74%) of the placebo group (adjusted odds ratio, 0.86 [95% CI 0.63-1.19]). The most commonly occurring events in the primary outcome in both groups were preterm birth, neonatal hypoglycemia, and delivery of a large-for-gestational-age infant. The study was halted at 75% accrual for futility in detecting a significant difference in the primary outcome. Prespecified secondary outcomes and subgroup analyses were similar between groups. Of individual components of the composite adverse neonatal outcome, metformin-exposed neonates had lower odds to be large for gestational age (adjusted odds ratio, 0.63 [95% CI, 0.46-0.86]) when compared with the placebo group. Conclusions and Relevance: Using metformin plus insulin to treat preexisting type 2 or gestational diabetes diagnosed early in pregnancy did not reduce a composite neonatal adverse outcome. The effect of reduction in odds of a large-for-gestational-age infant observed after adding metformin to insulin warrants further investigation. Trial Registration: ClinicalTrials.gov Identifier: NCT02932475.

Response to Medical Nutritional Therapy and Need for Pharmacological Therapy in Women with Gestational Diabetes.

OBJECTIVE: We assessed if the initial response to medical nutritional therapy (MNT) can help predict the need for pharmacological therapy in women with gestational diabetes mellitus (GDM). STUDY DESIGN: We identified 1,174 women with GDM who underwent standardized dietary counseling and reported glucose values from the first week of MNT. We compared women who required pharmacological therapy with those who did not use bivariate statistics, and used multivariable logistic regression modeling to assess for factors predicting the need for pharmacological therapy. RESULTS: We identified 819 women (69.8%) who needed pharmacological therapy. They had higher prepregnancy body mass index, higher rates of GDM diagnosis before 24 weeks, and higher oral glucose tolerance test values. After adjustment for covariates, age (odds ratio [OR]: 1.04; 95% confidence interval [CI]: 1.01-1.08), obesity (OR: 2.49; 95% CI: 1.70-3.66), and ≥33% of abnormal glucose values from the first week of MNT (OR: 13.84; 95% CI: 9.4-20.20) were associated with the need for pharmacological therapy. Area under the curve of the regression model was 0.83, with a sensitivity of 72.2%, a specificity of 86.8%, and a positive predictive value of 92.5%. CONCLUSION: Glucose values from the first week of MNT were the strongest predictor of needing pharmacological therapy. Further studies are needed to define metabolic predictors of response to MNT in women with GDM.