Metformin vs insulin in the management of gestational diabetes: a systematic review and meta-analysis

Time-in-Range With Insulin Versus Metformin in Gestational Diabetes Mellitus Using Continuous Glucose Monitoring: A Randomized Control Study at a Tertiary Care Centre in South India

Background The prevalence of gestational diabetes mellitus (GDM) is increasing globally. When diet and lifestyle modifications are inadequate for control, managing GDM often involves insulin or metformin. Metformin's oral administration option improves patient compliance and acceptance, but concerns about its use persist, necessitating careful evaluation. Comparative studies between insulin and metformin in GDM are scarce. In pregnancies complicated by diabetes, precise glucose control is crucial for maternal-fetal well-being, and continuous glucose monitoring (CGM) plays a valuable role in achieving recommended targets. CGM provides comprehensive glucose profiles, including postprandial glucose excursions and details about time spent in hypoglycemia, euglycemia, and hyperglycemia. The time-in-range (TIR) metric, when used alongside A1C, offers more actionable information than A1C alone. To the best of our knowledge, no published trials compare TIR in GDM with metformin or insulin aspart/detemir, specifically focusing on CGM metrics. This randomized controlled trial (RCT) aims to assess TIR in women with GDM treated with either metformin or insulin. Materials and methods This study was a non-inferiority randomized control trial evaluating TIR in GDM using continuous glucose monitoring with metformin or insulin. Forty-four women with GDM were enrolled. The diagnosis of GDM was based on the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria. CGM readings were collected for 14 days after sensor activation. Results In our study, 44 women with GDM completed the protocol, with 22 in the Metformin group and 22 in the Insulin group. Baseline characteristics did not differ between the groups. Age, BMI pre-gravid, BMI at 28 weeks, parity, family history of diabetes mellitus, previous history of GDM, glycated hemoglobin (HbA1c), oral glucose tolerance tests (OGTT) at zero hours, one hour, and two hours, as well as gestational weeks, did not significantly differ between the two groups. The metformin and insulin groups did not differ significantly in CGM metrics, including TIR, time above range, time below range, mean glucose, and glucose management indicator. Conclusion Based on our findings, the metformin and insulin groups did not differ in CGM metrics, including TIR, time above range, time below range, mean glucose, and glucose management indicator. In clinical practice, CGM metrics complement fasting blood glucose, postprandial glucose, and HbA1c as appropriate and useful clinical targets and outcome measurements. Metformin's oral administration option offers advantages such as improved patient compliance and acceptance in women with GDM.

Short-term neonatal outcomes in women with gestational diabetes treated using metformin versus insulin: a systematic review and meta-analysis of randomized controlled trials

AIMS

To expand the evidence base for the clinical use of metformin, we conducted a meta-analysis of randomized controlled trials (RCTs) comparing the efficacy and safety of metformin versus insulin with respect to short-term neonatal outcomes.

METHODS

A comprehensive search of electronic databases (PubMed, Embase, Cochrane Library, and Web of Science) was performed. Two reviewers extracted the data and calculated pooled estimates by use of a random-effects model. In total, 24 studies involving 4355 participants met the eligibility criteria and were included in the quantitative analyses.

RESULTS

Unlike insulin, metformin lowered neonatal birth weights (mean difference - 122.76 g; 95% confidence interval [CI] - 178.31, - 67.21; p < 0.0001), the risk of macrosomia (risk ratio [RR] 0.68; 95% CI 0.54, 0.86; p = 0.001), the incidence of neonatal intensive care unit admission (RR 0.73; 95% CI 0.61, 0.88; p = 0.0009), and the incidence of neonatal hypoglycemia (RR 0.65; 95% CI 0.52, 0.81; p = 0.0001). Subgroup analysis based on the maximum daily oral dose of metformin indicated that metformin-induced neonatal birth weight loss was independent of the oral dose.

CONCLUSIONS

Our meta-analysis provides further evidence that metformin is a safe oral antihyperglycemic drug and has some benefits over insulin when used for the treatment of gestational diabetes, without an increased risk of short-term neonatal adverse outcomes. Metformin may be particularly useful in women with gestational diabetes at high risk for neonatal hypoglycemia, women who want to limit maternal and fetal weight gain, and women with an inability to afford or use insulin safely.

Major malformations risk following early pregnancy exposure to metformin: a systematic review and meta-analysis

Metformin is considered as first-line treatment for type 2 diabetes and an effective treatment for polycystic ovary syndrome (PCOS). However, evidence regarding its safety in pregnancy is limited. We conducted a systematic review and meta-analysis of major congenital malformations (MCMs) risk after first-trimester exposure to metformin in women with PCOS and pregestational diabetes mellitus (PGDM). Randomized controlled trials (RCTs) and observational cohort studies with a control group investigating risk of MCM after first-trimester pregnancy exposure to metformin were searched until December 2021. ORs and 95% CIs were calculated separately according to indications and study type using Mantel-Haenszel method; outcome data were combined using random-effects model. Eleven studies (two RCTs; nine observational cohorts) met the inclusion criteria: four included pregnant women with PCOS, four included those with PGDM and three evaluated both indications separately and were considered in both indication groups. In PCOS group, there were two RCTs (57 exposed, 52 control infants) and five observational studies (472 exposed, 1892 control infants); point estimates for MCM rates in RCTs and observational studies were OR 0.93 (95% CI 0.09 to 9.21) (I²=0%; Q test=0.31; p value=0.58) and OR 1.35 (95% CI 0.37 to 4.90) (I²=65%; Q test=9.43; p value=0.05), respectively. In PGDM group, all seven studies were observational (1122 exposed, 1851 control infants); the point estimate for MCM rates was OR 1.05 (95% CI 0.50 to 2.18) (I²=59%; Q test=16.34; p value=0.01). Metformin use in first-trimester pregnancy in women with PCOS or PGDM do not meaningfully increase the MCM risk overall. However, further studies are needed to characterize residual safety concerns.

Role of Beta Cell Function and Insulin Resistance in the Development of Gestational Diabetes Mellitus

Background: Gestational diabetes mellitus (GDM) is a pregnancy complication characterized by second trimester hyperglycemia. Untreated, GDM is related to an increased risk for adverse pregnancy outcomes. Both beta cell dysfunction and insulin resistance underlie impaired glucose tolerance. Understanding the dominant mechanism predisposing to GDM may be important to provide effective treatment in order to improve perinatal outcomes. We hypothesize that insulin resistance rather that beta cell dysfunction predisposes to GDM. Methods: A 75g oral glucose tolerance test (OGTT) was performed on 2112 second-trimester pregnant women to determine the relationship between insulin resistance (HOMA-IR), beta cell function (HOMA-β), and the prevalence of abnormal glucose handling. Results: High insulin resistance raised the risk of GDM (relative risk (RR) 6.1, 95% confidence interval (CI) (4.4–8.5)), as did beta cell dysfunction (RR 3.8, 95% CI (2.7–5.4)). High insulin resistance, but not beta cell function, enhances the necessity for additional glucose lowering medication on top of a low carbohydrate diet in women diagnosed with GDM. Conclusions: Both high insulin resistance and beta cell dysfunction increase the risk of GDM. As increased insulin resistance, rather than beta cell function, is related to an insufficient response to a low carbohydrate diet, we speculate that insulin sensitizers rather than insulin therapy may be the most targeted therapeutic modality in diet-insensitive GDM.

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

AIMS/INTRODUCTION

Despite there being several meta-analyses on the effects of antidiabetic agents in patients with gestational diabetes mellitus, the reliability of their findings is a concern, mainly due to undetermined methodological quality of these studies. This study aimed to assess the methodological quality of available meta-analyses and provide a summary estimation of the effectiveness of treatments modalities.

MATERIALS AND METHODS

PubMed, Web of Science and Scopus databases were comprehensively searched for retrieving relevant meta-analyses published in English up to May 2020. A Measurement Tool to Assess Systematic Reviews (AMSTAR-2) was applied to evaluate methodological quality of eligible meta-analyses. A network meta-analysis was used to calculate the pooled odds ratio of maternal and neonatal outcomes in gestational diabetes mellitus patients treated with metformin or glyburide compared with those treated with insulin. The rank network analysis was carried out for ranking of the treatments and reporting the most efficient treatment.

RESULTS

A total of 27 and 17 studies were included for qualitative and quantitative syntheses, respectively; of these, just four studies were classified as high quality. The results showed that metformin had the highest probability of being the best treatment, compared with insulin and glyburide, for the majority of adverse neonatal outcomes, whereas glyburide was the best treatment in reducing the risk of adverse maternal outcomes. The results were not significantly changed after excluding low-quality studies.

CONCLUSIONS

This review study of available literature shows that metformin can be a superior option in most neonatal and maternal adverse pregnancy outcomes in women with gestational diabetes mellitus; the results need to be further updated by including future more qualified studies.

Metformin is comparable to insulin for pharmacotherapy in gestational diabetes mellitus: A network meta-analysis evaluating 6046 women

CONTEXT

The comparative efficacy of gestational diabetes (GDM) treatments lack conclusive evidence for choice of first-line treatment.

OBJECTIVES

The aim of this study was to compare the efficacy of metformin and glibenclamide to insulin using a core outcome set (COS) to unify outcomes across trials investigating the treatment of gestational diabetes mellitus.

STUDY DESIGN

A network meta-analysis (NMA) was conducted.

DATA-SOURCE

PubMed, Embase, and Cochrane Controlled Register of Trials were searched from inception to January 2020.

STUDY SELECTION

RCTs that enrolled pregnant women who were diagnosed with GDM and that compared the efficacy of different pharmacological interventions for the treatment of GDM were included.

META-ANALYSIS

A generalized pairwise modelling framework was employed.

RESULTS

A total of 38 RCTs with 6046 participants were included in the network meta-analysis. Compared to insulin, the estimated effect of metformin indicated improvements for weight gain (WMD -2·39 kg; 95% CI -3·31 to -1·46), maternal hypoglycemia (OR 0.34; 95% CI 0.12 to 0·97) and LGA (OR 0.61; 95% CI 0.38 to 0·98). There were also improvements in estimated effects for neonatal hypoglycemia (OR 0.48; 95% CI 0.19 to 1·25), pregnancy induced hypertension (OR 0.63; 95% CI 0.37 to 1·06), and preeclampsia (OR 0.74; 95% CI 0.538 to 1·04), though with limited evidence against our model hypothesis of equivalence with insulin for these outcomes.

CONCLUSION

Metformin is, at least, comparable to insulin for the treatment of GDM. Glibenclamide appears less favorable, in comparison to insulin, than metformin.

Effects of metformin treatment on pregnancy outcomes in patients with polycystic ovary syndrome

INTRODUCTION

This review covers the current evidence regarding the use of metformin as a therapeutic intervention for optimizing pregnancy outcomes in women with polycystic ovary syndrome (PCOS).

AREAS COVERED

After searching Medline, Embase and CINAHL, all important large clinical trials and observational studies plus systematic reviews, meta-analyses and Cochrane reviews have been summarized here. The results have been compared to culminate in a thorough review and discussion on the use of metformin in relation to reproductive outcomes for women with PCOS. The role of metformin in PCOS is explored both in terms of achieving conception and during pregnancy. The existing evidence around metformin use is summarized both during the preconceptual period and during pregnancy, in relation to reproductive outcomes.

EXPERT OPINION

Metformin is a widely used medication, often prescribed to improve reproductive outcomes for women with PCOS. However, the evidence remains equivocal regarding its efficacy both in optimizing fertility and pregnancy outcomes. More research is required with special emphasis on metformin use within different populations, including ethnic groups and women with varying BMI ranges.

Improvement Effect of Metformin on Female and Male Reproduction in Endocrine Pathologies and Its Mechanisms

Metformin (MF), a first-line drug to treat type 2 diabetes mellitus (T2DM), alone and in combination with other drugs, restores the ovarian function in women with polycystic ovary syndrome (PCOS) and improves fetal development, pregnancy outcomes and offspring health in gestational diabetes mellitus (GDM) and T2DM. MF treatment is demonstrated to improve the efficiency of in vitro fertilization and is considered a supplementary drug in assisted reproductive technologies. MF administration shows positive effect on steroidogenesis and spermatogenesis in men with metabolic disorders, thus MF treatment indicates prospective use for improvement of male reproductive functions and fertility. MF lacks teratogenic effects and has positive health effect in newborns. The review is focused on use of MF therapy for restoration of female and male reproductive functions and improvement of pregnancy outcomes in metabolic and endocrine disorders. The mechanisms of MF action are discussed, including normalization of metabolic and hormonal status in PCOS, GDM, T2DM and metabolic syndrome and restoration of functional activity and hormonal regulation of the gonadal axis.

Metformin during Pregnancy: Effects on Offspring Development and Metabolic Function

Maternal obesity during pregnancy and gestational diabetes mellitus (GDM) are both associated with of several postnatal diseases in the offspring, including obesity, early onset hypertension, diabetes mellitus, and reproductive alterations. Metformin is an oral drug that is being evaluated to treat GDM, obesity-associated insulin resistance, and polycystic ovary syndrome (PCOS) during pregnancy. The beneficial effects of metformin on glycemia and pregnancy outcomes place it as a good alternative for its use during pregnancy. In this line of thought, improving the metabolic status of the pregnant mother by using metformin should avoid the consequences of insulin resistance on the offspring's fetal and postnatal development. However, some human and animal studies have shown that metformin during pregnancy could amplify these alterations and be associated with excessive postnatal weight gain and obesity. In this minireview, we discuss not only the clinical and experimental evidence that supports the benefits of using metformin during pregnancy but also the evidence showing a possible negative impact of this drug on the offspring's development.

Metformin and Pregnancy Outcomes: Evidence Gaps and Unanswered Questions

BACKGROUND

Metformin is sometimes used as an alternative to insulin in gestational diabetes mellitus (GDM). It is also used to achieve ovulation in polycystic ovary syndrome (PCOS). Pre-natal exposure to metformin results from its continuation after a successful ovulation in women with PCOS, its maintenance in women with pre-gestational diabetes or the installation of metformin in GDM. Little is known about the potential consequences of metformin exposure on pregnancy outcomes and offspring development. The aim of this review is to summarize the metformin effects on pregnancy outcomes and offspring development. Gaps in the available evidence and unanswered questions are also discussed.

METHODS

A comprehensive literature search was carried out to identify eligible studies from MEDLINE/PubMed, EMBASE and SCIELO databases through 1995 first semester.

RESULTS

Several factors limit the effect of metformin on embryos. In contrast, placental transport of metformin is effective allowing for a higher fetal exposure; the impact of this finding remains unclear. It seems that the interruption of metformin after a pregnancy diagnosis in women with PCOS is not associated with a higher miscarriage risk and it continuation does not seem to impair the maternal metabolic prognosis or prevent emerging GDM.

CONCLUSIONS

It seems to have no sense to prolong the use of metformin after a pregnancy diagnosis in women with PCOS. Patients with GDM may be treated with metformin under on judicious basis, and a careful attachment to clinical guidelines and regulations is recommended. The long-term effects of pre-natal exposure to metformin on the offspring remain uncertain.

Comparative Efficacy and Safety of Metformin, Glyburide, and Insulin in Treating Gestational Diabetes Mellitus: A Meta-Analysis

To compare the efficacy and safety of metformin, glyburide, and insulin in treating gestational diabetes mellitus (GDM), a meta-analysis of randomized controlled trials (RCTs) was conducted. PubMed, Embase, CINAHL, Web of Science, and Cochrane Library to November 13, 2018, were searched for RCT adjusted estimates of the efficacy and safety of metformin, glyburide, and insulin treatments in GDM patients. There were 41 studies involving 7703 GDM patients which were included in this meta-analysis; 12 primary outcomes and 24 secondary outcomes were detected and analyzed. Compared with metformin, insulin had a significant increase in the risk of preeclampsia (RR, 0.57; 95% CI, 0.45 to 0.72; P < 0.001), NICU admission (RR, 0.75; 95% CI, 0.64 to 0.87; P < 0.001), neonatal hypoglycemia (RR, 0.57; 95% CI, 0.49 to 0.66; P < 0.001), and macrosomia (RR, 0.68; 95% CI, 0.55 to 0.86; P < 0.05). To the outcomes of birth weight and gestational age at delivery, insulin had a significant increase when compared with metformin (MD, 114.48; 95% CI, 37.32 to 191.64; P < 0.01; MD, 0.23; 95% CI, 0.12 to 0.34; P < 0.001; respectively). Of the two groups between glyburide and metformin, metformin had lower gestational weight gain compared with glyburide (MD, 1.67; 95% CI, 0.26 to 3.07; P < 0.05). Glyburide had a higher risk of neonatal hypoglycemia compared with insulin (RR, 1.76; 95% CI, 1.32 to 2.36; P < 0.001). This meta-analysis found that metformin could be a safe and effective treatment for GDM. However, clinicians should pay attention on the long-term offspring outcomes of the relative data with GDM patients treated with metformin. Compared with insulin, glyburide had a higher increase of neonatal hypoglycemia. The use of glyburide in pregnancy for GDM women appears to be unclear.

Longer-term outcomes in offspring of GDM mothers treated with metformin versus insulin

Insulin has traditionally been the gold standard pharmacological treatment for gestational diabetes mellitus (GDM). Insulin requires multiple injections a day, can cause frequent hypoglycaemia, requires careful handling, and is generally more expensive compared to oral agents. Metformin has been increasingly popular in recent years. Based on the short-term data available, metformin appears to be safe and effective for the treatment of GDM but existing studies have all stressed the lack of longer-term offspring data. This article will analyse the evidence available on the longer-term outcomes in the offspring of women with GDM treated with metformin versus insulin. Pubmed, EMBASE, CENTRAL, and CNKI were searched for follow-up studies of randomised controlled trials that compared metformin with insulin for the treatment of GDM. Existing follow-up studies did not find any significant increase in the risk of adverse effects in terms of growth and development in the offspring of GDM mothers managed with metformin versus insulin.

Metformin in the management of diabetes during pregnancy and lactation

This review explores the current place of metformin in the management of gestational diabetes (GDM) and type 2 diabetes during pregnancy and lactation. The rationale and basic pharmacology of metformin usage in pregnancy is discussed along with the evidence from observational and randomized controlled trials in women with GDM or overt diabetes. There seems to be adequate evidence of efficacy and short-term safety of metformin in relation to maternal and neonatal outcomes in GDM, with possible benefits related to lower maternal weight gain and lower risk of neonatal hypoglycemia and macrosomia. Additionally, metformin offers the advantages of oral administration, convenience, less cost and greater acceptability. Metformin may, therefore, be considered in milder forms of GDM where glycemic goals are not attained by lifestyle modification. However, failure rate is likely to be higher in those with an earlier diagnosis of GDM, higher blood glucose, higher body mass index (BMI) or previous history of GDM, and insulin remains the cornerstone of pharmacological treatment in such cases. The use of metformin in type 2 diabetes has been assessed in observational and small randomized trials. Metformin monotherapy in women with overt diabetes is highly unlikely to achieve glycemic targets. Hence, the use should be restricted as adjunct to insulin and may be considered in women with high insulin dose requirements or rapid weight gain. There is clearly a need for more clinical trials to assess the effect of combined insulin plus metformin therapy in pregnancy with type 2 diabetes. Additionally, there is a paucity of data on long-term effects in offspring exposed to metformin in utero. It is imperative to further explore its impact on offspring as metformin has significant transplacental transfer and has the potential to impact the programming of the epigenome. Therefore, caution must be exercised when prescribing metformin in pregnant women. More research is clearly needed before metformin can be considered as standard of care in the management of diabetes during pregnancy.

Metformin treatment of type 2 diabetes mellitus in pregnancy: update on safety and efficacy

With the increasing prevalence of type 2 diabetes mellitus (T2DM) in women of childbearing age, prescribing antidiabetic medications in first-trimester pregnancy is becoming more common. Metformin treatment during this time is usually avoided in countries with well-resourced healthcare. This is based on historical concerns about safety to the foetus and the widespread availability of insulin. However, there is now increasing interest in the potential benefits of metformin in pregnant women with T2DM. In this commentary, the main evidence supporting metformin safety in pregnancy is summarized, with an emphasis on the first trimester. Based on a structured literature search, the recent randomized controlled trials comparing metformin and insulin are reviewed. We then show that prescribing advice for metformin in pregnancy is inconsistent and product information/package inserts (PI) are universally out of date. This causes confusion and pushes some women and their clinicians to change from metformin to insulin. The potential advantages of metformin in pregnant women with T2DM are then discussed, including oral dosing and improved acceptability, lower resource utilization and cost, decreased insulin requirements, less maternal weight gain and less risk of maternal and neonatal hypoglycaemia. The conclusion is that metformin is a cheap and efficacious antidiabetic medication for many pregnant women with T2DM, with reasonable evidence for safety. Drug information resources should be updated so that metformin can be considered more broadly in women with T2DM who present for antenatal care.

Gestational diabetes from A to Z

Gestational diabetes mellitus (GDM) is defined as any degree of hyperglycaemia that is recognized for the first time during pregnancy. This definition includes cases of undiagnosed type 2 diabetes mellitus (T2DM) identified early in pregnancy and true GDM which develops later. GDM constitutes a greater impact on diabetes epidemic as it carries a major risk of developing T2DM to the mother and foetus later in life. In addition, GDM has also been linked with cardiometabolic risk factors such as lipid abnormalities, hypertensive disorders and hyperinsulinemia. These might result in later development of cardiovascular disease and metabolic syndrome. The understanding of the different risk factors, the pathophysiological mechanisms and the genetic factors of GDM, will help us to identify the women at risk, to develop effective preventive measures and to provide adequate management of the disease. Clinical trials have shown that T2DM can be prevented in women with prior GDM, by intensive lifestyle modification and by using pioglitazone and metformin. However, a matter of controversy surrounding both screening and management of GDM continues to emerge, despite several recent well-designed clinical trials tackling these issues. The aim of this manuscript is to critically review GDM in a detailed and comprehensive manner, in order to provide a scientific analysis and updated write-up of different related aspects.

Comparative efficacy and safety of oral antidiabetic drugs and insulin in treating gestational diabetes mellitus: An updated PRISMA-compliant network meta-analysis

BACKGROUND

The safety and efficacy of different drugs in treatment of gestational diabetes mellitus (GDM) patients who could not maintain normal glucose level only through diet and exercise remains to be debated. We performed this network meta-analysis (NAM) to compare and rank different antidiabetic drugs in glucose level control and pregnancy outcomes in GDM patients.

METHODS

We searched PubMed, Cochrane Library, Web of Science, and Embase up to December 31, 2016. Randomized controlled trials (RCTs) related to different drugs in the treatment of GDM patients were enrolled. We extracted the relevant information and assessed the risk of bias with the Cochrane risk of bias tool. We did pair-wise meta-analyses using the fixed-effects model or random-effects model and then adopted random-effects NAM combining both direct and indirect evidence within a Bayesian framework, to calculate the odds ratio (OR) or standardized mean difference (SMD) and to draw a surface under the cumulative ranking curve of the neonatal and maternal outcomes of different treatments in GDM patients.

RESULTS

Thirty-two randomized controlled trials (RCTs) were included in this NAM, including 6 kinds of treatments (metformin, metformin plus insulin, insulin, glyburide, acarbose, and placebo). The results of the NAM showed that regarding the incidence of macrosomia and LGA, metformin had lower incidence than glyburide (OR, 0.5411 and 0.4177). In terms of the incidence of admission to the NICU, insulin had higher incidence compared with glyburide (OR, 1.844). As for the incidence of neonatal hypoglycemia, metformin had lower incidence than insulin and glyburide (OR, 0.6331 and 0.3898), and insulin was lower than glyburide (OR, 0.6236). For mean birth weight, metformin plus insulin was lower than insulin (SMD, -0.5806), glyburide (SMD, -0.7388), and placebo (SMD, -0.6649). Besides, metformin was observed to have lower birth weight than glyburide (SMD, 0.2591). As for weight gain, metformin and metformin plus insulin were lower than insulin (SMD, -0.9166, -1.53). Ranking results showed that glyburide might be the optimum treatment regarding average glucose control, and metformin is the fastest in glucose control for GDM patients; glyburide have the highest incidence of macrosomia, preeclampsia, hyperbilirubinemia, neonatal hypoglycemia, shortest gestational age at delivery, and lowest mean birth weight; metformin (plus insulin when required) have the lowest incidence of macrosomia, PIH, LGA, RDS, low gestational age at delivery, and low birth weight. Besides, insulin had the highest incidence of NICU admission, acarbose had the lowest risk of neonatal hypoglycemia.

CONCLUSION

Our study concluded that metformin is fastest in glucose control, with a more favorable pregnancy outcomes-would be a better option, but its rate of glucose control is the lowest.However, glyburide is the optimumtreatment regarding the rate of glucose control, but withmore adverse outcomes. This NAMbased on 32 RCTs will strongly help to guide further development of management for GDM patients, clinicians should carefully balance the risk-benefit profile of different treatments according to various situations.

Comparison of glyburide and insulin in the management of gestational diabetes: A meta-analysis

Objective

The aim of this meta-analysis was to determine the efficacy and safety of glyburide as a treatment for gestational diabetes mellitus (GDM) compared to insulin.

Methods

A meta-analysis was conducted to compare the management of gestational diabetes with glyburide and insulin. Studies fulfilling all of the following inclusion criteria were included in this meta-analysis: subjects were women with gestational diabetes requiring drug treatment; the comparison treatment included glyburide vs insulin; one or more outcomes (maternal or neonatal) should be provided in the individual study; the study design should be a randomized control trial. Exclusion criteria: non-RCT studies; non-human data. PubMed, Embase and CENTRAL databases were searched from inception until 10 October 2016.

Results

Ten randomized control trials involving 1194 participants met the inclusion criteria and were included. 13 primary outcomes (6 maternal, 7 neonatal) and 26 secondary outcomes (9 maternal, 17 neonatal) were detected and analyzed in this study. Glyburide significantly increased the risk of any neonatal hypoglycemia [risk ratio (RR), 1.89; 95% confidence interval (95%CI), 1.26 to 2.82; p = 0.002]. Sensitivity analysis confirmed robustness of this result [RR, 2.29; 95%CI, 1.49 to 3.54; p = 0.0002]. No differences were observed between the two groups with respect to birth weights [mean difference (MD), 79; 95%CI, -64 to 221.99; p = 0.28] and the risk of macrosomia [RR, 1.69; 95%CI, 0.57 to 5.08; p = 0.35].

Conclusion

For women with gestational diabetes, no differences in maternal short term outcomes were observed in those treated with glyburide or insulin. However, the incidence of neonatal hypoglycemia was higher in the glyburide group compared to the insulin group.

Treatments for gestational diabetes: a systematic review and meta-analysis

OBJECTIVE

To investigate the effectiveness of different treatments for gestational diabetes mellitus (GDM).

DESIGN

Systematic review, meta-analysis and network meta-analysis.

METHODS

Data sources were searched up to July 2016 and included MEDLINE and Embase. Randomised trials comparing treatments for GDM (packages of care (dietary and lifestyle interventions with pharmacological treatments as required), insulin, metformin, glibenclamide (glyburide)) were selected by two authors and double checked for accuracy. Outcomes included large for gestational age, shoulder dystocia, neonatal hypoglycaemia, caesarean section and pre-eclampsia. We pooled data using random-effects meta-analyses and used Bayesian network meta-analysis to compare pharmacological treatments (ie, including treatments not directly compared within a trial).

RESULTS

Forty-two trials were included, the reporting of which was generally poor with unclear or high risk of bias. Packages of care varied in their composition and reduced the risk of most adverse perinatal outcomes compared with routine care (eg, large for gestational age: relative risk0.58 (95% CI 0.49 to 0.68; I2=0%; trials 8; participants 3462). Network meta-analyses suggest that metformin had the highest probability of being the most effective treatment in reducing the risk of most outcomes compared with insulin or glibenclamide.

CONCLUSIONS

Evidence shows that packages of care are effective in reducing the risk of most adverse perinatal outcomes. However, trials often include few women, are poorly reported with unclear or high risk of bias and report few outcomes. The contribution of each treatment within the packages of care remains unclear. Large well-designed and well-conducted trials are urgently needed.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42013004608.

Gestational Diabetes Mellitus:current knowledge and unmet needs

Gestational diabetes mellitus (GDM) is a global health concern, not only because its prevalence is high and on the increase, but also because of the potential implications for the health of mothers and their offspring. Unfortunately, there is considerable controversy in the literature surrounding the diagnosis and treatment of GDM, as well as the possible long-term consequences for the offspring. As a result, worldwide there is a lack of uniformly accepted diagnostic criteria and the advice regarding the treatment of GDM, including diet, insulin therapy, and the use of oral blood glucose-lowering agents, is highly variable. In this review we provide an overview of the important issues in the field of GDM, including diagnostic criteria, different treatment regimens available, and the long-term consequences of GDM in the offspring.

Neurodevelopmental outcome at 2 years in offspring of women randomised to metformin or insulin treatment for gestational diabetes

OBJECTIVE

Gestational diabetes mellitus (GDM) is a common complication of pregnancy and is increasingly being treated with metformin that crosses the placenta rather than insulin, which does not. This study seeks to examine the neurodevelopment of offspring of women treated with metformin or insulin for GDM.

DESIGN

We performed a prospective follow-up study of children whose mothers had been randomly assigned at 20-33 weeks gestation to treatment with metformin or insulin for GDM. Of the 211 children followed up at 2 years, 128 were from Auckland, New Zealand (64 metformin vs 64 insulin), and 83 from Adelaide, Australia (39 metformin vs 49 insulin). Neurodevelopment was examined with the Bayley Scales of Infant Development V.2 mental development index (MDI) and psychomotor development index (PDI). Clinical and demographic background characteristics were obtained at enrolment, birth and follow-up.

RESULTS

No significant differences were found between treatment groups in clinical or demographic characteristics. The MDI and PDI composite scores were tested with general linear models. No significant differences were found between metformin and insulin, respectively, in New Zealand (MDI, M=83.6 vs 86.9 and PDI, M=83.4 vs M=85.2) or Australia (MDI, M=102.5 vs M=98.4 and PDI, M=105.6 vs M=99.9) and no interactions observed. The differences in neurodevelopmental outcomes between the Auckland and Adelaide cohorts were explained by parental ethnicity, infant birth weight >4000 g, neonatal hypoglycaemia, maternal glycaemia and smoking in the household.

CONCLUSIONS

This study provides additional data supporting the safety of metformin in the treatment of GDM.

TRIAL REGISTRATION NUMBER

ACTRN 12605000311651.

Antidiabetic activity of perylenequinonoid-rich extract from Shiraia bambusicola in KK-Ay mice with spontaneous type 2 diabetes mellitus

ETHNOPHARMACOLOGICAL RELEVANCE

Bitter and cold traditional Chinese medicines (TCMs) have been long used to treat diabetes mellitus (DM) based on unique medical theory system since ancient China. As one of bitter and cold TCMs, the stromatas of Shiraia bambusicola have been used for the treatment of DM and exerted clinical effects to a certain extent. However, the corresponding active principles and antidiabetic mechanism of the TCM still remain unknown. Therefore, the aim of the present investigation was to evaluate the potential antidiabetic effect of the active Shiraia bambusicola EtOAc extract (SB-EtOAc) in vitro and in vivo, and elucidate its probable antidiabetic mechanism.

MATERIALS AND METHODS

A LC-PDA-ESIMS protocol was developed to determine the chemical principles of the active EtOAc extract rapidly and unambiguously. The effect of SB-EtOAc on the glucose transporter type 4 (GLUT4) translocation and glucose uptake in L6 cells was examined. SB-EtOAc was orally administration at the dose of 30, 60 and 120mg/kg/d in KK-Ay mice, for 21 days. Body weight, plasma glucose, oral glucose tolerance test, fasted blood glucose levels, oral glucose tolerance test and insulin tolerance test, serum insulin and blood-lipid indexes were measured. GLUT4 on L6 cells membrane and phosphorylation of the AMP-activated protein kinase (p-AMPK) expression in L6 cells were measured. The GLUT4 and p-AMPK expression in KK-Ay mice skeletal muscle were measured. Phosphorylation of the acetyl-CoA carboxylase (p-ACC) and p-AMPK were measured.

RESULTS

In vitro, SB-EtOAc exhibited a strong effect of stimulation on GLUT4 translocation by 3.2 fold in L6 cells compared with basal group, however, the selective AMPK inhibitor compound C can completely inhibit the AMPK pathway and prevent the GLUT4 translocation caused by SB-EtOAc. The further western blotting experiments showed that SB-EtOAc can stimulate AMPK phosphorylation in L6 cells and improve the expression of GLUT4. In vivo, SB-EtOAc can improve the KK-Ay mice insulin resistant and oral glucose tolerance to a certain extent. And the body weight, blood glucose levels and the serum TC, TG, FFA, AST, ALT and LDL-C were significantly reduced and HDL-C were increased after 3 weeks treatment. Mechanistically, phosphorylation of the AMPK and ACC had been improved obviously and the levels of AMPK phosphorylation and GLUT4 had been also enhanced.

CONCLUSION

In vitro, SB-EtOAc exhibited a strong effect of stimulation on GLUT4 translocation and improved significantly the glucose uptake. In vivo, SB-EtOAc significantly improved oral glucose tolerance and the insulin resistant as well as glucolipid metabolism. In this study, SB-EtOAc displayed promising positive antidiabetic activity in vitro and in vivo, partly by modulating AMPK-GLUT4 and AMPK-ACC signaling pathways.

Metformin in women with type 2 diabetes in pregnancy (MiTy): a multi-center randomized controlled trial

Background

The incidence of type 2 diabetes in pregnancy is rising and rates of serious adverse maternal and fetal outcomes remain high. Metformin is a biguanide that is used as first-line treatment for non-pregnant patients with type 2 diabetes. We hypothesize that metformin use in pregnancy, as an adjunct to insulin, will decrease adverse outcomes by reducing maternal hyperglycemia, maternal insulin doses, maternal weight gain and gestational hypertension/pre-eclampsia. In addition, since metformin crosses the placenta, metformin treatment of the fetus may have a direct beneficial effect on neonatal outcomes. Our aim is to compare the effectiveness of the addition of metformin to insulin, to standard care (insulin plus placebo) in women with type 2 diabetes in pregnancy.

Methods

The MiTy trial is a multi-centre randomized trial currently enrolling pregnant women with type 2 diabetes, who are on insulin, between the ages of 18–45, with a gestational age of 6 weeks 0 days to 22 weeks 6 days. In this randomized, double-masked, parallel placebo-controlled trial, after giving informed consent, women are randomized to receive either metformin 1,000 mg twice daily or placebo twice daily. A web-based block randomization system is used to assign women to metformin or placebo in a 1:1 ratio, stratified for site and body mass index. The primary outcome is a composite neonatal outcome of pregnancy loss, preterm birth, birth injury, moderate/severe respiratory distress, neonatal hypoglycemia, or neonatal intensive care unit admission longer than 24 h. Secondary outcomes are large for gestational age, cord blood gas pH < 7.0, congenital anomalies, hyperbilirubinemia, sepsis, hyperinsulinemia, shoulder dystocia, fetal fat mass, as well as maternal outcomes: maternal weight gain, maternal insulin doses, maternal glycemic control, maternal hypoglycemia, gestational hypertension, preeclampsia, cesarean section, number of hospitalizations during pregnancy, and duration of hospital stays. The trial aims to enroll 500 participants.

Discussion

The results of this trial will inform endocrinologists, obstetricians, family doctors, and other healthcare professionals caring for women with type 2 diabetes in pregnancy, as to the benefits of adding metformin to insulin in this high risk population.

Trial registration

ClinicalTrials.gov Identifier: no. NCT01353391. Registered February 6, 2009.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-016-0954-4) contains supplementary material, which is available to authorized users.

Metformin for the treatment of gestational diabetes: An updated meta-analysis

OBJECTIVE

To assess the efficacy of metformin and insulin in the treatment of pregnant women with gestational diabetes mellitus (GDM).

METHODS

A meta-analysis was conducted by including randomized controlled trials comparing metformin and insulin in GDM. An electronic search was conducted to identify relevant studies. Data were synthesized by a random effects meta-analysis model. A Bayesian analysis was also performed to account for uncertainties in the treatment efficacy.

RESULTS

Eight clinical trials involving 1712 individuals were included in the final analysis. The pooled estimates of metformin-insulin differences were very small and statistically non-significant in fasting plasma glucose, postprandial plasma glucose and HbA1c, measured at 36-37 weeks of gestation. Notably, 14-46% of those receiving metformin required additional insulin. Compared with the insulin group, metformin treatment was associated with a lower incidence of neonatal hypoglycemia (relative risk, RR 0.74; 95% CI 0.58-0.93; P=0.01) and of neonatal intensive care admission (RR 0.76; 95% CI 0.59-0.97; P=0.03). Bayesian analysis revealed that the efficacy of metformin was consistently higher than insulin with a probability of over 98% on these two neonatal complications. Other outcomes were not significantly different between the two treatment groups.

CONCLUSION

In women with gestational diabetes, metformin use and insulin therapy have comparable glycemic control profile, but metformin use was associated with lower risk of neonatal hypoglycemia.

Changing trends in management of gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is on the rise globally. In view of the increasing prevalence of GDM and fetal and neonatal complications associated with it, there is a splurge of research in this field and management of GDM is undergoing a sea change. Trends are changing in prevention, screening, diagnosis, treatment and future follow up. There is emerging evidence regarding use of moderate exercise, probiotics and vitamin D in the prevention of GDM. Regarding treatment, newer insulin analogs like aspart, lispro and detemir are associated with better glycemic control than older insulins. Continuous glucose monitoring systems and continuous subcutaneous insulin systems may play a role in those who require higher doses of insulin for sugar control. Evidence exists that favors metformin as a safer alternative to insulin in view of good glycemic control and better perinatal outcomes. As the risk of developing GDM in subsequent pregnancies and also the risk of overt diabetes in later life is high, regular assessment of these women is required in future. Lifestyle interventions or metformin should be offered to women with a history of GDM who develop pre-diabetes. Further studies are required in the field of prevention of GDM for optimizing obstetric outcome.

Metformin in gestational diabetes: An emerging contender

Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance occurring first time during pregnancy. Its prevalence is simultaneously increasing with the global rise of diabesity. GDM commonly develops, when maternal glucose metabolism is unable to compensate for the progressive development of insulin resistance, arising primarily from the consistently rising diabetogenic placental hormones. It classically develops during the second or third trimester. Theoretically, insulin sensitizers should have been the ideal agent in its treatment, given the insulin resistance, the major culprit in its pathogenesis. Fortunately, majority of women can be treated satisfactorily with lifestyle modification, and approximately 20% requires more intensive treatment. For several decades, insulin has been the most reliable treatment strategy and the gold standard in GDM. Metformin is effective insulin sensitizing agent and an established first line drug in type 2 diabetes currently. As it crosses the placenta, a safety issue remains an obstacle and, therefore, metformin is currently not recommended in the treatment of GDM. Nevertheless, given the emerging clinically equivalent safety and efficacy data of metformin compared to insulin, it appears that it may perhaps open a rather new door in managing GDM. The aim of this review is to critically analyze, the safety and efficacy data of metformin regarding its use in GDM and pregnant mothers with polycystic ovarian disease, which has emerged in past decades.

Oral antidiabetic agents in gestational diabetes: a narrative review of current evidence

Gestational diabetes mellitus (GDM) classically occurs when maternal glucose metabolism is unable to compensate the progressive development of insulin resistance that arises from the continuously rising diabetogenic placental hormones. Although most women can be treated satisfactorily with diet alone, some require more intensive treatment. Insulin has been the most reliable treatment strategy in GDM over several decades. Although a long time has passed since the publication of two randomized controlled trials suggesting comparable efficacy and safety of metformin and glibenclamide, international bodies have not yet approved these oral agents. However, with the consistently emerging efficacy and safety data of these two drugs in the past decade, they may perhaps open a rather new door. The aim of this narrative review is to critically evaluate the existing evidence regarding safety and efficacy of oral drugs in GDM accumulated since the first publication in year 2000, suggesting clinical equivalency of glibenclamide (glyburide).

Glibenclamide, metformin, and insulin for the treatment of gestational diabetes: a systematic review and meta-analysis

OBJECTIVE

To summarize short term outcomes in randomized controlled trials comparing glibenclamide or metformin versus insulin or versus each other in women with gestational diabetes requiring drug treatment.

DESIGN

Systematic review and meta-analysis.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomized controlled trials that fulfilled all the following: (1) published as full text; (2) addressed women with gestational diabetes requiring drug treatment; (3) compared glibenclamide v insulin, metformin v insulin, or metformin v glibenclamide; and (4) provided information on maternal or fetal outcomes.

DATA SOURCES

Medline, CENTRAL, and Embase were searched up to 20 May 2014.

OUTCOMES MEASURES

We considered 14 primary outcomes (6 maternal, 8 fetal) and 16 secondary (5 maternal, 11 fetal) outcomes.

RESULTS

We analyzed 15 articles, including 2509 subjects. Significant differences for primary outcomes in glibenclamide v insulin were obtained in birth weight (mean difference 109 g (95% confidence interval 35.9 to 181)), macrosomia (risk ratio 2.62 (1.35 to 5.08)), and neonatal hypoglycaemia (risk ratio 2.04 (1.30 to 3.20)). In metformin v insulin, significance was reached for maternal weight gain (mean difference -1.14 kg (-2.22 to -0.06)), gestational age at delivery (mean difference -0.16 weeks (-0.30 to -0.02)), and preterm birth (risk ratio 1.50 (1.04 to 2.16)), with a trend for neonatal hypoglycaemia (risk ratio 0.78 (0.60 to 1.01)). In metformin v glibenclamide, significance was reached for maternal weight gain (mean difference -2.06 kg (-3.98 to -0.14)), birth weight (mean difference -209 g (-314 to -104)), macrosomia (risk ratio 0.33 (0.13 to 0.81)), and large for gestational age newborn (risk ratio 0.44 (0.21 to 0.92)). Four secondary outcomes were better for metformin in metformin v insulin, and one was worse for metformin in metformin v glibenclamide. Treatment failure was higher with metformin than with glibenclamide.

CONCLUSIONS

At short term, in women with gestational diabetes requiring drug treatment, glibenclamide is clearly inferior to both insulin and metformin, while metformin (plus insulin when required) performs slightly better than insulin. According to these results, glibenclamide should not be used for the treatment of women with gestational diabetes if insulin or metformin is available.Systematic review registration NCT01998113.

Effect comparison of metformin with insulin treatment for gestational diabetes: a meta-analysis based on RCTs

PURPOSE

To compare the effects of metformin with insulin on maternal and neonatal outcomes in gestational diabetes mellitus (GDM).

METHODS

A literature search in PUBMED, EMBASE, Science Direct, Springer link, and Cochrane library was conducted using the following search terms: "Gestational Diabetes" or "GDM", and "insulin" and "metformin". Quality assessment of included studies was determined with Quality Assessment of Diagnostic Accuracy Studies. Review Manger 5.2 was used to analyze mean difference (MD)/risk ratio (RR) and 95 % confidence interval (CI) in random-effects model or fixed-effects model depending on the level of heterogeneity.

RESULTS

A total of 11 studies were identified. There was no significant difference of the effect on maternal outcomes between the two treatments in glycohemoglobin A1c levels (P = 0.37), fasting blood glucose (P = 0.66), and the incidence of preeclampsia (P = 0.26); whereas, significantly reduced results were found in the metformin group in pregnancy-induced hypertension (PIH) rate (RR = 0.53, 95 % CI 0.31-0.90, P = 0.02), average weight gains after enrollment (MD = -1.28, 95 % CI -1.54 to -1.01, P < 0.0001), and average gestational ages at delivery (MD = 0.94, 95 % CI -0.21 to -0.01, P = 0.03). Regarding neonatal outcomes, when compared with insulin group, metformin presented significantly lower average birth weights (MD = -44.35, 95 % CI -85.79 to -2.90, P = 0.04), incidence of hypoglycemia (RR = 0.69, 95 % CI 0.55-0.87, P = 0.001) and neonatal intensive care unit (NICU) (RR = 0.82, 95 % CI 0.67-0.99, P = 0.04).

CONCLUSION

Metformin can significantly reduce several adverse maternal and neonatal outcomes including PIH rate, incidence of hypoglycemia and NICU, thus it may be an effective and safe alternative or additional treatment to insulin for GDM women.

Placental dysfunction in obese women and antenatal surveillance strategies

This review is aimed at discussing placental dysfunction in obesity and its clinical implication in pregnancy as well as an antenatal surveillance strategy for these women. Maternal obesity is associated with adverse perinatal outcome. Obesity is an independent risk factor for fetal hyperinsulinaemia, birthweight and newborn adiposity. Maternal obesity is associated with childhood obesity and obesity in adult life. Obesity induces a low-grade inflammatory response in placenta, which results in short- and long-term programming of obesity in fetal life. Preconception and antenatal counselling on obstetrics risk in pregnancy, on diet and lifestyle in pregnancy and on gestational weight gain is associated with a better outcome. Fetal growth velocity is closely associated with maternal weight and gestational weight gain. Careful monitoring of gestational weight gain and fetal growth, and screening and management of obstetrical complications such as gestational diabetes and pre-eclampsia, improves perinatal outcome. The use of metformin in non-diabetic obese women is under investigation; further evidence is required before recommending it.