Undiagnosed Asymptomatic Hypoglycemia

Benefits and harms associated with an increase in gestational diabetes diagnosis in Queensland, Australia: a retrospective cohort comparison of diagnosis rates, outcomes, interventions and medication use for two periods, 2011-2013 and 2016-2018, using a large perinatal database

OBJECTIVES

To assess benefits and harms arising from increasing gestational diabetes (GDM) diagnosis, including for women with normal-sized babies.

DESIGN, SETTING AND PARTICIPANTS

Diagnosis rates, outcomes, interventions and medication use are compared in a retrospective cohort study of 229 757 women birthing in public hospitals of the Australian State of Queensland during two periods, 2011-2013 and 2016-2018, using data from the Queensland Perinatal Data Collection.

OUTCOME MEASURES

Comparisons include hypertensive disorders, caesarean section, shoulder dystocia and associated harm, induction of labour (IOL), planned birth (PB), early planned birth <39 weeks (EPB), spontaneous labour onset with vaginal birth (SLVB) and medication use.

RESULTS

GDM diagnosis increased from 7.8% to 14.3%. There was no improvement in shoulder dystocia associated injuries, hypertensive disorders or caesarean sections. There was an increase in IOL (21.8%-30.0%; p<0.001), PB (36.3% to 46.0%; p<0.001) and EPB (13.5%-20.6%; p<0.001), and a decrease in SLVB (56.0%-47.3%; p<0.001). Women with GDM experienced an increase in IOL (40.9%-49.8%; p<0.001), PB (62.9% to 71.8%; p<0.001) and EPB (35.3%-45.7%; p<0.001), and a decrease in SLVB (30.01%-23.6%; p<0.001), with similar changes for mothers with normal-sized babies. Of women prescribed insulin in 2016-2018, 60.4% experienced IOL, 88.5% PB, 76.4% EPB and 8.0% SLVB. Medication use increased from 41.2% to 49.4% in women with GDM, from 3.2% to 7.1% in the antenatal population overall, from 3.3% to 7.5% in women with normal-sized babies and from 2.21% to 4.38% with babies less than the 10th percentile.

CONCLUSION

Outcomes were not apparently improved with increased GDM diagnosis. The merits of increased IOL or decreased SLVB depend on the views of individual women, but categorising more pregnancies as abnormal, and exposing more babies to the potential effects of early birth, medication effects and growth limitation may be harmful.

Antenatal maternal hypoglycemia in women with gestational diabetes mellitus and neonatal outcomes

OBJECTIVE

To examine the prevalence of antenatal maternal hypoglycemia after initiation of pharmacotherapy for gestational diabetes mellitus (GDMA2) and its association with pregnancy outcomes.

STUDY DESIGN

Retrospective cohort of GDMA2 women receiving either insulin or oral hypoglycemic agents. Composite neonatal outcome included macrosomia, jaundice, respiratory distress syndrome, large for gestational age, shoulder dystocia, birth trauma, 5-minute Apgar < 7, and neonatal hypoglycemia, and was compared between women with and without hypoglycemia using bivariate and multivariate analyses.

RESULTS

Of 489 women included in the study, 95 (19.4%) had at least one episode of hypoglycemia, most often in the setting of glyburide. Newborns exposed to maternal hypoglycemia had higher rates of the composite neonatal outcome (54.7% vs. 38.3%, p = 0.004). After controlling for confounding factors, maternal hypoglycemia remained independently associated with the composite neonatal outcome (aOR = 1.69, 95% CI 1.04-2.72).

CONCLUSION

Maternal hypoglycemia in GDMA2 was associated with higher rates of adverse neonatal outcomes.

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.

The timing of initiation of pharmacotherapy for women with gestational diabetes mellitus

BACKGROUND

The decision to initiate pharmacotherapy is integral in the care for pregnant women with gestational diabetes mellitus (GDM). We sought to compare pregnancy outcomes between two threshold percentages of elevated glucose values prior to initiation of pharmacotherapy for GDM. We hypothesized that a lower threshold at pharmacotherapy initiation will be associated with lower rates of adverse perinatal outcomes.

METHODS

This was a retrospective cohort study of women with GDM delivering in a single tertiary care center. Pregnancy outcomes were compared using bivariable and multivariable analyses between women who started pharmacotherapy (insulin or oral hypoglycemic agent) after a failed trial of dietary modifications at two different ranges of elevated capillary blood glucose (CBG) values: Group 1 when 20-39% CBG values were above goal; Group 2 when ≥40% CBG values were above goal. The primary outcome was a composite GDM-associated neonatal adverse outcome that included: macrosomia, large for gestational age (LGA), shoulder dystocia, hypoglycemia, hyperbilirubinemia requiring phototherapy, respiratory distress syndrome, stillbirth, and neonatal demise. Secondary outcomes included cesarean delivery, preterm birth (< 37 weeks), neonatal intensive care unit (NICU) admission, and small for gestational age (SGA).

RESULTS

A total of 417 women were included in the study. In univariable analysis, the composite neonatal outcome was statistically significantly higher in Group 2 compared to Group 1 (47.9% vs. 31.4%, p = 0.001). In addition, rates of preterm birth (15.7% vs 7.4%, p = 0.011), NICU admission (11.7% vs 4.0%, p = 0.006), and LGA (21.2% vs 9.1% p = 0.001) were higher in Group 2. In contrast, higher rates of SGA were noted in Group 1 (8.0% vs. 2.9%, p = 0.019). There was no difference in cesarean section rates. These findings persisted in multivariable analysis after adjusting for confounding factors (composite neonatal outcome aOR = 0.50, 95%CI [0.31-0.78]).

CONCLUSIONS

Initiation of pharmacotherapy for GDM when 20-39% of CBG values are above goal, compared to ≥40%, was associated with decreased rates of adverse neonatal outcomes attributable to GDM. This was accompanied by higher rates of SGA among women receiving pharmacotherapy at the lower threshold. Additional studies are required to identify the optimal threshold of abnormal CBG values to initiate pharmacotherapy for GDM.

SUGAR-DIP trial: oral medication strategy versus insulin for diabetes in pregnancy, study protocol for a multicentre, open-label, non-inferiority, randomised controlled trial

INTRODUCTION

In women with gestational diabetes mellitus (GDM) requiring pharmacotherapy, insulin was the established first-line treatment. More recently, oral glucose lowering drugs (OGLDs) have gained popularity as a patient-friendly, less expensive and safe alternative. Monotherapy with metformin or glibenclamide (glyburide) is incorporated in several international guidelines. In women who do not reach sufficient glucose control with OGLD monotherapy, usually insulin is added, either with or without continuation of OGLDs. No reliable data from clinical trials, however, are available on the effectiveness of a treatment strategy using all three agents, metformin, glibenclamide and insulin, in a stepwise approach, compared with insulin-only therapy for improving pregnancy outcomes. In this trial, we aim to assess the clinical effectiveness, cost-effectiveness and patient experience of a stepwise combined OGLD treatment protocol, compared with conventional insulin-based therapy for GDM.

METHODS

The SUGAR-DIP trial is an open-label, multicentre randomised controlled non-inferiority trial. Participants are women with GDM who do not reach target glycaemic control with modification of diet, between 16 and 34 weeks of gestation. Participants will be randomised to either treatment with OGLDs, starting with metformin and supplemented as needed with glibenclamide, or randomised to treatment with insulin. In women who do not reach target glycaemic control with combined metformin and glibenclamide, glibenclamide will be substituted with insulin, while continuing metformin. The primary outcome will be the incidence of large-for-gestational-age infants (birth weight >90th percentile). Secondary outcome measures are maternal diabetes-related endpoints, obstetric complications, neonatal complications and cost-effectiveness analysis. Outcomes will be analysed according to the intention-to-treat principle.

ETHICS AND DISSEMINATION

The study protocol was approved by the Ethics Committee of the Utrecht University Medical Centre. Approval by the boards of management for all participating hospitals will be obtained. Trial results will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NTR6134; Pre-results.

Application and Utility of Continuous Glucose Monitoring in Pregnancy: A Systematic Review

Background: In the past decade, continuous glucose monitoring (CGM) has been proven to have similar accuracy to self-monitoring of blood glucose (SMBG) and yet provides better therapy optimization and detects trends in glucose values due to higher frequency of testing. Even though the feasibility and utility of CGM has been proven successfully in Type 1 and 2 diabetes, there is a lack of knowledge of its application and effectiveness in pregnancy, especially in gestational diabetes mellitus (GDM). In this review, we aimed to summarize and evaluate the updated scientific evidence on the application of CGM in pregnancies complicated with GDM. Methods: A search using keywords related to CGM and GDM on PubMed was conducted and articles were filtered based on full text, year of publication (Jan 1998-Dec 2018), human subject studies, and written in English. Reviews and duplicate articles were removed. A final total of 29 articles were included in this review. Results: In terms of maternal and fetal outcomes, inconsistent evidence was reported. Among GDM patients using CGM and SMBG, two randomized controlled trials (RCTs) found no significant differences in macrosomia, birth weight (BW), and gestational age (GA) at delivery between these two groups, while one prospective cohort found a lower incidence of cesarean section and macrosomia in CGM use subjects. Furthermore, CGM use was consistently found to have increased detection in dysglycemia and glycemic variability compared to SMBG. In terms of clinical utility, CGM use led to more treatment adjustments and lower gestational weight gain (GWG). Lastly, CGM use showed higher postprandial glucose levels in GDM-complicated pregnancies than in normal pregnancies. Conclusion: Current updated evidence suggests that CGM is superior to SMBG among GDM pregnancies in terms of detecting hypoglycemic and hyperglycemic episodes, which might result in an improvement of maternal and fetal outcomes. In addition, CGM detects a wider glycemic variability in GDM mothers than non-GDM controls. Further research with larger sample sizes and complete pregnancy coverage is needed to explore the clinical utility such as screening and predictive values of CGM for GDM.

Continuous glucose monitoring results in lower HbA1c in Malaysian women with insulin-treated gestational diabetes: a randomized controlled trial

AIMS

To determine if therapeutic, retrospective continuous glucose monitoring (CGM) improves HbA_1c with less hypoglycaemia in women with insulin-treated gestational diabetes mellitus (GDM).

METHODS

This prospective, randomized controlled, open-label trial evaluated 50 women with insulin-treated GDM randomized to either retrospective CGM (6-day sensor) at 28, 32 and 36 weeks' gestation (Group 1, CGM, n = 25) or usual antenatal care without CGM (Group 2, control, n = 25). All women performed seven-point capillary blood glucose (CBG) profiles at least 3 days per week and recorded hypoglycaemic events (symptomatic and asymptomatic CBG < 3.5 mmol/l; non-fasting < 4.0 mmol/l). HbA_1c was measured at 28, 33 and 37 weeks. In Group 1, both CGM and CBG data were used to manage diabetes, whereas mothers in Group 2 were managed based on CBG data alone.

RESULTS

Baseline characteristics (age, pre-pregnancy BMI, HbA_1c , total insulin dose) were similar between groups. There was a lower increase in HbA_1c from 28 to 37 weeks' gestation in the CGM group [∆HbA_1c : CGM + 1 mmol/mol (0.09%), control + 3mmol/mol (0.30%); P = 0.024]. Mean HbA_1c remained unchanged throughout the trial in the CGM group, but increased significantly in controls as pregnancy advanced. Mean HbA_1c in the CGM group was lower at 37 weeks compared with controls [33 ± 4 mmol/mol (5.2 ± 0.4%) vs. 38 ± 7 mmol/mol (5.6 ± 0.6%), P < 0.006]. Some 92% of the CGM group achieved an HbA_1c ≤ 39 mmol/mol (≤ 5.8%) at 37 weeks compared with 68% of the control group (P = 0.012). Neither group experienced severe hypoglycaemia.

CONCLUSION

CGM use may be beneficial in insulin-treated GDM because it improves HbA_1c compared with usual antenatal care without increasing severe hypoglycaemia. (Clinical Trials Registry No.: NCT02204657).

Pharmacological treatment of gestational diabetes mellitus: point/counterpoint

Controversies persist over the most efficacious pharmacologic treatment for gestational diabetes mellitus. For purposes of accuracy in this article, the individual American College of Obstetricians and Gynecologists Practice Bulletin and American Diabetes Association Standards of Medical Care positions on each issue are quoted and then deliberated with evidence of counter claims presented in point/counterpoint. This is a review of all the relevant evidence for the most holistic picture possible. The main issues are (1) which diabetic drugs cross the placenta, (2) the quality of evidence and data source validity, (3) the rationale for the designation of glucose control as the primary outcome in gestational diabetes mellitus, and (4) which drugs (metformin, glyburide, or insulin) are most effective in improving secondary outcomes. The concept that 1 drug fits all, whether it be insulin, glyburide, or metformin, is a fallacy. Different drugs provide certain benefits but not all the benefits and not to all patients. In addition, the steps in the gestational diabetes mellitus management decision path and the current cost of the use of insulin, glyburide, or metformin are addressed. In the future, we must consider studying the potential of diabetic drugs that currently are used in nonpregnancy and incorporating the concept of precision medicine in the decision tree to maximize pregnancy outcomes.

Prenatal counseling on type 2 diabetes risk, exercise, and nutrition affects the likelihood of postpartum diabetes screening after gestational diabetes

OBJECTIVE

Screening rates for type 2 diabetes after a pregnancy with gestational diabetes are inadequate. We aimed to determine how prenatal counseling on exercise, nutrition, and type 2 diabetes risk affects postpartum screening for diabetes.

METHODS

Using Pregnancy Risk Assessment Monitoring System data from Colorado (2009-2011) and Massachusetts (2012-2013), we performed multivariable logistic regression to examine the relationship between prenatal counseling and postpartum screening.

RESULTS

Among 556 women, prenatal counseling was associated with increased postpartum diabetes screening, after adjusting for age; parity; and receipt of Women, Infants, and Children (WIC) benefits (adjusted odds ratio (AOR) 3.0 [95% CI 1.4-6.5]). This effect was modified by race/ethnicity. Primiparity (AOR 2.2 [95% CI 1.2-4.1]) and advanced maternal age (AOR 2.2 [95% CI 1.2-3.8]) were associated with increased screening, and receiving WIC benefits was associated with decreased screening (AOR 0.5 [95% CI 0.3-0.9]).

CONCLUSIONS

In women with gestational diabetes, culturally appropriate counseling on future diabetes risk, nutrition, and exercise may enhance postpartum diabetes screening.

Masked hypoglycemia in pregnancy

BACKGROUND

Hypoglycemia is a major hindrance for optimal glycemic control in women with gestational diabetes mellitus (GDM) on insulin. In the present study, masked hypoglycemia (glucose <2.77mmol/L for ≥30 min) was estimated in pregnant women using a continuous glucose monitoring (CGM) system.

METHODS

Twenty pregnant women with GDM on insulin (cases) and 10 age-matched euglycemic pregnant women (controls) between 24 and 36 weeks gestation were recruited. Both groups performed self-monitoring of blood glucose (SMBG) and underwent CGM for 72 h to assess masked hypoglycemia. Masked hypoglycemic episodes were further stratified into two groups based on interstitial glucose (2.28-2.77 and ≤2.22 mmol/L).

RESULTS

Masked hypoglycemia was recorded in 35% (7/20) of cases and 40% (4/10) of controls using CGM, with an average of 1.28 and 1.25 episodes per subject, respectively. Time spent at glucose levels between 2.28 and 2.77 mmol/L did not differ between the two groups (mean 114 vs 90 min; P = 0.617), but cases spent a longer time with glucose ≤2.2 mmol/L. Babies born to women with GDM were significantly lighter than those born to controls (2860 vs 3290 g; P = 0.012). There was no significant difference in birth weight within the groups among babies born to women with or without hypoglycemia.

CONCLUSION

Euglycemic pregnant women and those with GDM on insulin had masked hypoglycemia. Masked hypoglycemia was not associated with adverse maternal or fetal outcomes. Therefore, low glucose levels in the hypoglycemic range may represent a physiologic adaptation in pregnancy. This response is exaggerated in women with GDM on insulin.

Insulin detemir versus glyburide in women with gestational diabetes mellitus

AIM

To evaluate the safety, efficacy and pregnancy outcomes of insulin detemir (IDet) versus glyburide treatment in women with gestational diabetes mellitus (GDM).

METHODS

We conducted a retrospective cohort study of women with GDM who were treated with either glyburide or IDet for GDM in a university-affiliated tertiary hospital.

RESULTS

Ninety-one patients with GDM were enrolled, 62 were administered glyburide and 29 IDet. Maternal age, pregestational body mass index (BMI) and rate of abnormal oral glucose tolerance test (OGTT) blood glucose values were not significantly different between groups. Good glycemic control rates were comparable. Hypoglycemic episodes were reported only in the glyburide group (19.4% versus 0%, p = 0.01). Maternal weight gain during pregnancy was significantly higher among women in the glyburide group (8.8 ± 5.1 kg, p < 0.001) compared to those in the IDet group (2.1 ± 19.9 kg, p = 0.71).

CONCLUSIONS

To the best of our knowledge, this is the first study on IDet treatment in patients with GDM. By our preliminary results, IDet is a viable treatment option in women with GDM. Further large prospective studies are needed to determine the efficacy and safety of IDet in GDM patients.

Comparing twice- versus four-times daily insulin in mothers with gestational diabetes in Pakistan and its implications

BACKGROUND

Gestational diabetes mellitus is a common medical problem associated with maternal and fetal complications. Good glycemic control is the cornerstone of treatment.

OBJECTIVE

Compare outcomes between four times (q.i.d) and twice daily (b.i.d) regimens. The morning dose of the b.i.d regimen contained two-thirds of the total insulin, comprising a third human regular insulin and two-thirds human intermediate insulin; equal amounts in the evening.

METHODS

480 women at >30 weeks with gestational diabetes mellitus with failure to control blood glucose were randomly assigned to either regimen.

RESULTS

Mean time to the control of blood glucose was significantly less and glycemic control significantly increased with the q.i.d regimen. Operative deliveries, extent of neonatal hypoglycemia, babies with low Agpar scores and those with hyperbilirubinemia were significantly higher with the b.i.d daily regimen.

CONCLUSION

The q.i.d daily regime was associated with improved fetal and maternal outcomes. Consequently should increasingly be used in Pakistan, assisted by lower acquisition costs.

Pharmacokinetics, efficacy and safety of glyburide for treatment of gestational diabetes mellitus

INTRODUCTION

Gestational diabetes mellitus (GDM) complicates 10% of all pregnancies and is defined as hyperglycemia first noted during pregnancy. Rates of GDM are rising and untreated GDM results in complications for both mother and fetus. GDM is often managed by diet and exercise but 30-40% of women will require pharmacological intervention. Insulin has traditionally been the treatment of choice but since 2007, glyburide, a second generation sulfonylurea has become the most prescribed medication for GDM.

AREAS COVERED

This review will cover the pharmacokinetics, efficacy, and safety of glyburide for the management of GDM.

EXPERT OPINION

Management of GDM is challenging secondary to the stringent glycemic goals that mimic the lower glucose levels in pregnancy. Glyburide is generally effective in treating hyperglycemia. However, several studies have raised safety concerns showing higher neonatal intensive care unit (NICU) admissions, higher rates of macrosomia, large for gestational age and pre-eclampsia in the mother. For this reason, insulin should be first-line therapy for GDM. In areas of limited resources where the self-monitoring needed for accurate insulin dosing is not possible, where access to refrigeration for insulin storage is not universal, or severe needle phobia then the benefits of glyburide (controlling hyperglycemia) outweighs the harm of NICU admissions and macrosomia.

Oral hypoglycemic agents: do the ends justify the means?

BACKGROUND

Glyburide has replaced insulin as the first line of therapy in the treatment of gestational diabetes in the United States. Glyburide and metformin therapies were reported to be comparable to insulin yet also cost-effective, patient-friendly, and potentially compliance-enhancing. Recently, the efficacy of the use of these oral hypoglycemic drugs has been questioned. In this review, the questionable concerns will be addressed: Which diabetic drug(s) cross the placenta? What is the quality of evidence and the data source validity? Which treatment modalities are most effective in reducing the primary outcome in GDM? Which drug is most effective in improving secondary outcomes?

FINDINGS

This review documents the methodological issues in study design that have impacted the results for the provision of health care interventions in GDM. The review summarizes the contents of the articles qualitatively and assesses the theoretical and empirical evidence. Multiple types of studies exist and every study design serves a specific purpose. Different study designs addressing the same question can yield varying results. The risk of presenting uncertain results without categorically knowing the direction and magnitude of the effect holds true for both randomized and nonrandomized controlled trials. The review further emphasizes the importance of achieving the targeted levels of glycemic control.

CONCLUSION

The implications of this review are critical to addressing the current gaps in the literature on the efficacy of the use of oral hypoglycemic agents in GDM. The emphasis needs to be placed on patient treatment in order to manage hyperglycemia to reduce fetal and maternal morbidity. In this regard, we need to delineate proper outcome criteria that will reflect disease severity and treat using appropriate pharmacological therapy.

Weight gain in gestational diabetes: the effect of treatment modality

OBJECTIVE

To evaluate treatment effectiveness (diet alone, insulin or glyburide) on maternal weight gain in gestational diabetes (GDM).

METHODS

GDM patients were treated with diet alone, insulin or glyburide. Weight gain was stratified into: prior to GDM diagnosis, from diagnosis to delivery and total pregnancy weight gain. Good glycemic control was defined as mean blood glucose ≤ 105 mg/dl and obesity as Body Mass Index (BMI) ≥ 30 kg/m(2), overweight BMI 25-29 kg/m(2) and normal < 25 kg/m(2).

RESULTS

Total weight gain was similar in all the treatment groups. Two-thirds of weight gain occurred prior to diagnosis (diet 85%, insulin 67% and glyburide 78%). Post-diagnosis, patients on diet alone gained less weight than those on insulin or glyburide (p < 0.001); insulin-treated patients showed greater weight gain than glyburide-treated patients (p < 0.001). Patients on diet with good glycemic control showed less weight gain after diagnosis than patients on insulin or glyburide (2.8 ± 13, 6.6 ± 10, 5.2 ± 7.9 lbs, respectively, p < 0.02). Poorly-controlled patients, regardless of treatment, had similar patterns of weight gain throughout pregnancy.

CONCLUSION

Patterns of maternal weight gain in GDM pregnancies are associated with treatment modality and level of glycemic control.

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).

Trends in glyburide compared with insulin use for gestational diabetes treatment in the United States, 2000-2011

OBJECTIVE

To describe trends and identify factors associated with choice of pharmacotherapy for gestational diabetes (GDM) from 2000-2011 using a healthcare claims database.

METHODS

This was a retrospective cohort study of a large nationwide population of commercially insured women with GDM and pharmacy claims for glyburide or insulin before delivery, 2000-2011. We excluded women younger than 15 years or older than 50 years, those with prior noninsulin-dependent diabetes mellitus, or those who had multiple gestations. We estimated trends over time in the use of glyburide compared with insulin and prevalence ratios and 95% confidence intervals (CIs) for the association between covariates of interest and treatment with glyburide compared with insulin.

RESULTS

We identified 10,778 women with GDM treated with glyburide (n=5,873) or insulin (n=4,905). From 2000 to 2011, glyburide use increased from 7.4% to 64.5%, becoming the more common treatment in 2007. Women less likely to be treated with glyburide were those with metabolic syndrome (prevalence ratio 0.71, 95% CI 0.50-0.99), hyperandrogenism (prevalence ratio 0.77, 95% CI 0.62-0.97), polycystic ovarian syndrome (prevalence ratio 0.88, 95% CI 0.78-0.99), hypothyroidism (prevalence ratio 0.89, 95% CI 0.83-0.96), or undergoing infertility treatment (prevalence ratio 0.93, 95% CI 0.86-1.02). The probability of receiving glyburide decreased by 5% for every 10-year increase in maternal age (prevalence ratio 0.95, 95% CI 0.91-0.99). Among women prescribed with glyburide, 7.8% switched or augmented to a different drug class compared with 1.1% of insulin initiators.

CONCLUSION

Glyburide has replaced insulin as the more common pharmacotherapy for GDM over the past decade among those privately insured. Given its rapid uptake and the potential implications of suboptimal glucose control on maternal and neonatal health, robust evaluation of glyburide's relative effectiveness is warranted to inform treatment decisions for women with gestational diabetes.

LEVEL OF EVIDENCE

II.

The use of glyburide in the management of gestational diabetes mellitus: a meta-analysis

PURPOSE

Glyburide has been used for managing gestational diabetes mellitus (GDM) in a number of countries. It is rather inexpensive. However, its efficacy and safety remain controversial. With this meta-analysis, we evaluated glyburide in comparison with insulin.

MATERIAL/METHODS

With a systematic literature search strategy, a total of 93 randomized controlled trials (RCTs) with insulin and glyburide comparison were identified. Based on the revised Consolidated Standards of Reporting Trials (CONSORT) checklist, five of them met the inclusion criteria and were included in this meta-analysis.

RESULTS

Six hundred and seventy four subjects were included in these five RCTs. When compared with insulin, glyburide had an increased relative risk (RR) for neonatal hypoglycemia (RR: 1.98; 95% confidence interval [CI]: 1.17, 3.36). Estimation of standard mean differences (SMD) showed that both fetal birth weight and incidence of macrosomia were higher in subjects receiving glyburide than in those receiving insulin (SMD: 0.21; 95% CI: 0.06, 0.36; RR: 2.22; 95% CI: 1.07, 4.61 respectively). There were no significant differences in maternal glucose control, glycated hemoglobin, the rate of Cesarean section, large-for-gestational age, neonatal hypocalcemia, length of stay for neonatal ICU admissions, preterm birth, or congenital anomalies.

CONCLUSIONS

Our study suggested that in women with GDM, glyburide is as effective as insulin, but the risks of neonatal hypoglycemia, high fetal birth weight, and macrosomia were higher.

New technologies for the management of pregestational diabetes mellitus

PURPOSE OF THE REVIEW

The purpose of this review is to understand new modalities available to treat and manage type 1 and type 2 diabetes during pregnancy.

RECENT FINDINGS

The use of new insulin analogs and oral agents, as well as new technologies to deliver insulin and monitor glucose during pregnancy remains controversial. This review will outline the advantages and disadvantages, as well as the safety profiles of these new medications and therapeutic options.

SUMMARY

There are many effective treatments for diabetes during pregnancy. New insulin analogs seem to be safe to use in pregnancy and offer the potential for better glycemic control compared with older agents. Oral hypoglycemic medications also seem to be safe and may be an option for a select group of pregnant patients with type 2 diabetes. Insulin pumps and continuous glucose monitoring systems may be beneficial in certain patients, but adequate data are not yet available in terms of outcomes and cost-effectiveness to support widespread use.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After participating in this CME activity, physicians should be better able to revise glycemic goals for pregnant patients with pregestational diabetes to be in line with our current understanding of glycemic profiles in normal pregnant women. Use new insulin analogs to treat pregnant women with abnormalities in glucose homeostasis and choose which patients will benefit from advanced technologies for diabetes management, such as insulin pumps and continuous glucose monitoring systems.

Continuous glucose monitoring and insulin pump therapy for diabetes in pregnancy

Continuous glucose monitoring (CGM) systems and continuous subcutaneous insulin infusion (CSII) systems, or insulin pumps, offer great promise for improved glycemic control during pregnancy. Combined, these two devices could potentially constitute an artificial pancreas, where real-time blood glucose readings are relayed to an insulin pump that uses a personalized algorithm to decide how much insulin is needed by the patient's body. However, the promise of these two systems have not yet been proven individually or in combination in controlled clinical trials to improve pregnancy outcomes. Such trials are urgently needed before the widespread use of these devices in pregnancy can be justified.

Pregnancy and Diabetes Management: Advances and Controversies

BACKGROUND

The treatment of diabetes in pregnancy has potentially far-reaching benefits for both pregnant women with diabetes and their children and may provide a cost-effective approach to the prevention of obesity, type 2 diabetes mellitus, and metabolic syndrome. Early and accurate diagnosis of diabetes in pregnancy is necessary for optimizing maternal and fetal outcomes.

CONTENT

Optimal control of diabetes in pregnancy requires achieving normoglycemia at all stages of a woman's pregnancy, including preconception and the postpartum period. In this review we focus on new universal guidelines for the screening and diagnosis of diabetes in pregnancy, including the 75-g oral glucose tolerance test, as well as the controversy surrounding the guidelines. We review the best diagnostic and treatment strategies for the pregestational and intrapartum periods, labor and delivery, and the postpartum period, and discuss management algorithms as well as the safety and efficacy of diabetic medications for use in pregnancy.

SUMMARY

Global guidelines for screening, diagnosis, and classification have been established, and offer the potential to stop the cycle of diabetes and obesity caused by hyperglycemia in pregnancy. Normoglycemia is the goal in all aspects of pregnancy and offers the benefits of decreased short-term and long-term complications of diabetes.

Oral hypoglycemic agents for gestational diabetes mellitus?

INTRODUCTION

Gestational diabetes mellitus (GDM), the most frequent medical complication of pregnancy, is associated with several adverse outcomes over the short- and long-term for both mother and offspring. Standard treatment for GDM consists of insulin injections. Oral hypoglycemic agents (OHAs), on the other hand, are still the subject of controversy. Although OHAs are seemingly as efficient as insulin and may provide better quality of life, congenital malformations and unknown long-term effects are still feared.

AREAS COVERED

Recent data on the pharmacokinetics of two OHAs (glyburide and metformin) and their clinical use for GDM are reviewed, with a focus on clinical trials and observational studies comparing insulin with glyburide or metformin (1960 - 2010). The review will provide a comprehensive overview of the pros and cons of OHA usage, an appreciation of OHAs' efficiency for the purpose of controlling glycemia and embryogenetic basics relating to congenital malformations.

EXPERT OPINION

While insulin treatment is an effective therapy for controlling maternal glycemia, it nevertheless requires sufficient education and skills on the part of the patient to manage properly and may cause hypoglycemia, fear and anxiety. Oral treatment as a more user-friendly alternative may thus facilitate the control of GDM in some patients.

The use of oral antidiabetic medications in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is defined as carbohydrate intolerance with onset or first recognition during pregnancy. When medical nutrition therapy is not successful in maintaining target glucose values during pregnancy complicated by GDM, medication is required. Insulin has been the traditional treatment under such circumstances. The use of oral antidiabetic medications in the management of gestational diabetes has increased over the past several years. Recent studies have shown the equivalence to insulin of both glyburide and metformin in terms of pregnancy outcomes in GDM. However, both agents have been shown to cross the placenta to the fetus, and thus they should be used with caution and patients counseled appropriately.

New modalities in the treatment of pregnancies complicated by diabetes: drugs and devices

The development of drugs and devices in the treatment of pregnancies complicated by diabetes is in constant forward progression to compensate for pancreatic beta cell insufficiency. Maternal hyperglycemia during pregnancy is of particular interest due to the severe consequences that surface when a fetus is in development. The drugs that are currently recommended for use during pregnancy include rapid-acting insulin analogs lispro and aspart for meal-related bolus insulin and intermediate-acting NPH for basal insulin. Oral anti-diabetic agents are not recommended for use during pregnancy. Better control may be achieved with the incorporation of real-time glucose sensors and new insulin pumps with hopes of improving pregnancy outcome.

Benefits and risks of oral diabetes agents compared with insulin in women with gestational diabetes: a systematic review

OBJECTIVE

Little is known about the comparative risks and benefits of medical treatments for gestational diabetes mellitus (GDM). We conducted a systematic review of randomized controlled trials and observational studies of maternal and neonatal outcomes in women with GDM treated with oral diabetes agents compared with all types of insulin.

DATA SOURCES

We searched four electronic databases from inception through January 2007. Terms for GDM, insulins, and oral hypoglycemic agents were used in the search. Two investigators independently reviewed titles and abstracts, performed data abstraction on full articles, and assessed study quality.

METHOD OF STUDY SELECTION

Articles were excluded if they had no comparison group or did not use a standard diagnosis of GDM (3-hour, 100-g oral glucose tolerance test or 2-hour, 75-g oral glucose tolerance test). Nine studies met our inclusion criteria, four randomized controlled trials (n=1,229 participants) and five observational studies (n=831 participants). Data were abstracted on study characteristics, gestational age at treatment, medication dosage, and length of follow-up. Outcomes included glycemic control, infant birth weight, neonatal hypoglycemia, and congenital anomalies.

TABULATION, INTEGRATION, AND RESULTS

Two trials compared insulin to glyburide; one trial compared insulin, glyburide, and acarbose; and one trial compared insulin to metformin. No significant differences were found in maternal glycemic control or cesarean delivery rates between the insulin and glyburide groups. A meta-analysis showed similar infant birth weights between women treated with glyburide and women treated with insulin (mean difference -93 g) (95% confidence interval -191 to 5 g). There was a higher proportion of infants with neonatal hypoglycemia in the insulin group (8.1%) compared with the metformin group (3.3%) (P=.008). The rate of congenital malformations did not differ between pregnancies treated with insulin and those treated with oral agents. Observational studies were limited by selection bias and confounding.

CONCLUSION

No substantial maternal or neonatal outcome differences were found with the use of glyburide or metformin compared with use of insulin in women with GDM.

Use of new technologies for monitoring and treating diabetes in pregnancy

During the last century, there were two breakthroughs in diabetes management and monitoring that changed the course of treatment: the discovery of insulin and the progress in the understanding of glucose monitoring. As technology evolved, glucose monitoring and insulin administration can now be achieved in a continuous fashion. In this review, the authors focus on the utility of new technologies in the management and monitoring of diabetes in pregnancy.

Oral anti-hyperglycemic agents for the management of gestational diabetes mellitus

The purpose of this review is to provide a brief overview for understanding the management guidelines of gestational diabetes. The rationale for the use of oral antidiabetic drugs is provided based on validation by appropriately conducted research trials. Concerns over teratogenicity due to possible placental transfer, neonatal and maternal outcome, and basic pharmacologic benefits are addressed.

Glyburide for the treatment of gestational diabetes. A critical appraisal

The clinical experience with glyburide treatment of GDM has moved ahead of the science. A single randomized controlled trial of glyburide versus insulin indicates that glyburide treatment can provide a relatively safe alternative to insulin therapy. Subsequent retrospective trials have shown that up to 20% of GDM patients, especially those with substantial pretreatment hyperglycemia, are likely to require adjunctive or alternative therapy with insulin. These follow-on trials have also demonstrated that glyburide treatment, compared with insulin, actually results in lower mean glucose values and a higher percentage of "excellent glycemic control" with fewer hypoglycemic episodes. With the emerging view that glyburide treatment compared with insulin improves glycemic profiles, it should be expected to reduce the frequency of newborn obesity. Larger randomized controlled trials are necessary to clarify this question and the concerns regarding neonatal metabolic morbidity in glyburide-treated offspring.

Predictors of Glyburide Failure in the Treatment of Gestational Diabetes

OBJECTIVE

Our objective was to identify among women with gestational diabetes mellitus (GDM) the patient characteristics that predict treatment failure with glyburide.

METHODS

Historical cohort of 95 GDM women offered glyburide after dietary failure with defined entry criteria.

RESULTS

From November 2000 to May 2005, 118 women had 124 pregnancies and were offered glyburide therapy by the 2 codirectors of our Diabetes Clinic. All but 2 women elected glyburide, and 27 pregnancies were excluded due to criteria defined a priori to the study. A cohort of 95 women with 95 pregnancies were included for analysis. Nineteen percent failed glyburide. Significant predictors of failure were maternal age (34 years compared with 29 years, P = .001), earlier diagnosis of GDM (23 weeks compared with 28 weeks, P = .002), higher gravidity (P = .01) and parity (P = .03), and a higher mean fasting blood glucose (112 compared with 100 mg/dL; P = .045) compared with those successfully treated. After adjustment in the multivariable logistic regression analysis, GDM women diagnosed at a gestational age less than 25 weeks were 8.3 times more likely to fail glyburide compared with those diagnosed after 25 weeks. Maternal and fetal outcomes were favorable with a cesarean delivery rate of 25% and macrosomia rate of 7%.

CONCLUSION

Glyburide was more likely to fail in women diagnosed earlier in pregnancy, of older age and multiparity, and with higher fasting glucoses, suggesting that earlier glucose intolerance and a reduced capacity to respond to an insulin secretagogue may distinguish this group. The time for glyburide as an alternative treatment has come; however, it should be prescribed after careful consideration of these patient characteristics to minimize the likelihood of failure.

LEVEL OF EVIDENCE

II-2.

Glucagon secretion and autonomic signaling during hypoglycemia in late pregnancy

We examined net pancreatic norepinephrine (NE) spillover, pancreatic polypeptide (PP) release, and the decrement in C-peptide to identify factors involved in the blunted counterregulatory glucagon response in pregnancy. Conscious pregnant [pregnant hypoglycemic (Ph); 3rd trimester; n = 8] and nonpregnant [nonpregnant hypoglycemic (NPh); n = 6] dogs were studied during insulin-induced (approximately 12-fold basal insulin concentrations) hypoglycemia (plasma glucose 3.1 mM). Additional dogs were studied during hyperinsulinemic euglycemia [nonpregnant euglycemic (NPe), n = 4; pregnant euglycemic (Pe), n = 5; plasma glucose 6 mM]. Arterial glucagon concentrations declined similarly in NPe and Pe. Areas under the curve (AUCs) of the changes in glucagon and epinephrine were seven- and threefold greater in NPh than Ph (P < 0.05 between groups for both). Glucagon secretion fell below basal in NPe, Pe, and Ph but rose significantly in NPh. C-peptide declined 0.25 +/- 0.06, 0.12 +/- 0.11, 0.28 +/- 0.05, and 0.13 +/- 0.02 ng/ml in NPe, Pe, NPh, and Ph, respectively (P < 0.05, NPh vs. Ph). AUCs of NE spillover were 516 +/- 274, 265 +/- 303, 506 +/- 94, and -63 +/- 79 ng, respectively (P < 0.05, NPh vs. Ph). The AUC of PP release was approximately threefold greater in NPh than Ph (P < 0.05) but not different between euglycemic groups. The current evidence strongly suggests that the blunting of glucagon secretion during insulin-induced hypoglycemia in pregnancy is related to generalized impairment of a number of different signals, including parasympathetic and sympathoadrenal stimuli and altered sensing of circulating and/or intraislet insulin.

Hypoglycemia during the 100-g oral glucose tolerance test: incidence and perinatal significance

OBJECTIVE

To estimate and report the incidence and perinatal significance of hypoglycemia during the 100-g oral glucose tolerance test in pregnant women.

METHODS

Over a 3-year period, we analyzed the incidence and perinatal outcome of pregnant women who experienced hypoglycemia, defined as a plasma glucose level of 50 mg/dL or less while undergoing the 100-g oral glucose tolerance test. The study group included women who delivered singletons at term. Women who underwent the 100-g oral glucose tolerance test during the same period and had no hypoglycemia served as the control group.

RESULTS

A total of 805 women were included in the study, which comprised 51 women (6.3%) who experienced hypoglycemia during the test and 754 women in the control group. Gestational diabetes mellitus was diagnosed in 5/51 (9.8%) women in the study group, compared with 216/754 (28.6%) women in the control group (P < .03), and the neonates born to these women had significantly lower birth weights.

CONCLUSION

The incidence of reactive hypoglycemia during the 100-g oral glucose tolerance test in our population is 6.3%. Women who experience hypoglycemia during the test have a significantly lower incidence of gestational diabetes and neonatal birth weights.