Effectiveness of antidiabetic agents for treatment of gestational diabetes: A methodological quality assessment of meta-analyses and network meta-analysis

Epidemiology and management of gestational diabetes

Gestational diabetes is defined as hyperglycaemia first detected during pregnancy at glucose concentrations that are less than those of overt diabetes. Around 14% of pregnancies globally are affected by gestational diabetes; its prevalence varies with differences in risk factors and approaches to screening and diagnosis; and it is increasing in parallel with obesity and type 2 diabetes. Gestational diabetes direct costs are US$1·6 billion in the USA alone, largely due to complications including hypertensive disorders, preterm delivery, and neonatal metabolic and respiratory consequences. Between 30% and 70% of gestational diabetes is diagnosed in early pregnancy (ie, early gestational diabetes defined by hyperglycaemia before 20 weeks of gestation). Early gestational diabetes is associated with worse pregnancy outcomes compared with women diagnosed with late gestational diabetes (hyperglycaemia from 24 weeks to 28 weeks of gestation). Randomised controlled trials show benefits of treating gestational diabetes from 24 weeks to 28 weeks of gestation. The WHO 2013 recommendations for diagnosing gestational diabetes (one-step 75 gm 2-h oral glucose tolerance test at 24-28 weeks of gestation) are largely based on the Hyperglycemia and Adverse Pregnancy Outcomes Study, which confirmed the linear association between pregnancy complications and late-pregnancy maternal glycaemia: a phenomenon that has now also been shown in early pregnancy. Recently, the Treatment of Booking Gestational Diabetes Mellitus (TOBOGM) trial showed benefit in diagnosis and treatment of early gestational diabetes for women with risk factors. Given the diabesity epidemic, evidence for gestational diabetes heterogeneity by timing and subtype, and advances in technology, a life course precision medicine approach is urgently needed, using evidence-based prevention, diagnostic, and treatment strategies.

Long-Term Impact on Offspring (5 to 11 Years of Age) of Metformin Use in Pregnancy in Mothers With Diabetes: A Systematic Review and Meta-Analysis

OBJECTIVE

Data are scant on the impact of metformin use in gestational diabetes mellitus/diabetes in pregnancy on long-term outcomes in children and mothers beyond 5 years of childbirth. This systematic review and meta-analysis aimed to evaluate the long-term impact of metformin use in pregnancy on children and their mothers.

METHODS

Electronic databases were searched for studies evaluating metformin compared with insulin for managing gestational diabetes mellitus/diabetes in pregnancy. The primary outcome was the change in body mass index (BMI) in children at the ages of 5 to 11 years. The secondary outcomes were alterations in other anthropometric measures, obesity, and changes in the levels of lipids and adipocytokines in children and mothers.

RESULTS

Children at the age of 9 years born to mothers who were treated with metformin during pregnancy had similar BMI (mean difference [MD], 1.09 kg/m2 [95% confidence interval {CI}, -0.44 to 2.62]; P = .16; I2 = 16%), waist circumference-to-height ratio (MD, 0.13 [95% CI, -0.05 to 0.30]; P = .16; I2 = 94%), dual-energy X-ray absorptiometry (DXA) total fat mass (MD, 0.68 kg [95% CI, -2.39 to 3.79]; P = .66; I2 = 70%), DXA total fat percent (MD, 0.04% [95% CI, -3.44 to 3.51]; P = .98; I2 = 56%), DXA total fat-free mass (MD, 0.81 kg [95% CI, -0.96 to 2.58]; P = .37; I2 = 55%), magnetic resonance imaging visceral adipose tissue volume (MD, 80.97 cm3 [95% CI, -136.47 to 298.41]; P = .47; I2 = 78%), and magnetic resonance spectroscopy liver fat percentage (MD, 0.27% [95% CI, -1.26 to 1.79]; P = .73; I2 = 0%) to those born to mothers who were treated with insulin. Serum adiponectin, leptin, alanine aminotransferase, and ferritin were comparable among groups. In children between the ages of 9 and 11 years, the occurrence of obesity, diabetes, or challenges in motor and social development were comparable between the 2 groups. After 9 years of childbirth, BMI and the risk of developing diabetes were similar between the 2 groups of women.

CONCLUSION

Metformin use in pregnancy did not show any adverse effects compared with insulin on long-term outcomes in children and their mothers.

Focus on Metformin: Its Role and Safety in Pregnancy and Beyond

Metformin is used worldwide in the treatment of type 2 diabetes and has been used in the treatment of diabetes in pregnancy since the 1970s. It is highly acceptable to patients due to its ease of administration, cost and adverse effect profile. It is effective in reducing macrosomia, large-for-gestational-age infants and reduces maternal weight gain. Despite its many advantages, metformin has been associated with reductions in foetal size and has been associated with an increase in infants born small-for-gestational-age in certain cohorts. In this article, we review its efficacy, adverse effects and long-term follow-up before, during and after pregnancy for both mother and infant. We also evaluate the other forms of treatment for gestational diabetes, including oral therapies, insulin therapy and emerging treatments.

Efficacy and safety of hypoglycemic agents on gestational diabetes mellitus in women: A Bayesian network analysis of randomized controlled trials

Objective

To compare the efficacy and safety of metformin, glyburide, and insulin for GDM, we conducted a subgroup analysis of outcomes for women with GDM according to the International Association of Diabetes and Pregnancy Study Groups (IADPSG) diagnostic criteria.

Methods

We searched the NCBI, Embase, and Web of Science databases from inception to March 2022. Randomized controlled trials (RCTs) that compared the outcomes of hypoglycemic agents in women with GDM were included. Bayesian network analysis was employed.

Results

A total of 29 RCTs were included. Metformin was estimated to lead to a slight improvement in total gestational weight gain (WMD - 1.24 kg, 95% CI -2.38, -0.09), a risk of unmet treatment target in the sensitivity analysis (OR 34.50, 95% CI 1.18-791.37) than insulin. The estimated effect of metformin showed improvements in birth weight than insulin (WMD - 102.58 g, 95% CI -180.45 to -25.49) and glyburide (WMD - 137.84 g, 95% CI -255.31 to -25.45), for hypoglycemia within 1 h of birth than insulin (OR 0.65, 95% CI 0.47 to 0.84). The improvement in the estimated effect of metformin for hypoglycemia within 1 h of birth still existed when compared with glyburide (OR 0.41, 95% CI 0.26 to 0.66), whether in the IADPSG group (OR 0.33, 95% CI 0.12 to 0.92) or not (OR 0.43, 95% CI 0.20 to 0.98).

Conclusion

Metformin is beneficial for GDM women to control total GWG compared with insulin, regulate fetal birth weight more than insulin and glyburide, and increase the risk of unmet treatment targets compared with insulin. Compared to metformin, glyburide is associated with neonatal hypoglycemia.

Metformin: Sex/Gender Differences in Its Uses and Effects—Narrative Review

Metformin (MTF) occupies a major and fundamental position in the therapeutic management of type 2 diabetes mellitus (T2DM). Gender differences in some effects and actions of MTF have been reported. Women are usually prescribed lower MTF doses compared to men and report more gastrointestinal side effects. The incidence of cardiovascular events in women on MTF has been found to be lower to that of men on MTF. Despite some promising results with MTF regarding pregnancy rates in women with PCOS, the management of gestational diabetes, cancer prevention or adjunctive cancer treatment and COVID-19, most robust meta-analyses have yet to confirm such beneficial effects.