Insulin analogs and pregnancy: an update

Exercise as a Therapeutic Intervention in Gestational Diabetes Mellitus

Gestational Diabetes Mellitus (GDM) is defined as any degree of glucose intolerance with onset or first recognition during pregnancy. Regular exercise is important for a healthy pregnancy and can lower the risk of developing GDM. For women with GDM, exercise is safe and can affect the pregnancy outcomes beneficially. A single exercise bout increases skeletal muscle glucose uptake, minimizing hyperglycemia. Regular exercise training promotes mitochondrial biogenesis, improves oxidative capacity, enhances insulin sensitivity and vascular function, and reduces systemic inflammation. Exercise may also aid in lowering the insulin dose in insulin-treated pregnant women. Despite these benefits, women with GDM are usually inactive or have poor participation in exercise training. Attractive individualized exercise programs that will increase adherence and result in optimal maternal and offspring benefits are needed. However, as women with GDM have a unique physiology, more attention is required during exercise prescription. This review (i) summarizes the cardiovascular and metabolic adaptations due to pregnancy and outlines the mechanisms through which exercise can improve glycemic control and overall health in insulin resistance states, (ii) presents the pathophysiological alterations induced by GDM that affect exercise responses, and (iii) highlights cardinal points of an exercise program for women with GDM.

Pharmacologic Treatment of Diabetes in Pregnancy

Importance

Diabetes affects 6% to 9% of pregnancies, with gestational diabetes mellitus accounting for more than 90% of cases. Pregestational and gestational diabetes are associated with significant maternal and fetal risks; therefore, screening and treatment during pregnancy are recommended. Recommendations regarding the preferred treatment of diabetes in pregnancy have recently changed, with slight differences between American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) recommendations.

Objective

Our review discusses the diagnosis, management, and treatment of pregestational and gestational diabetes with the oral hypoglycemic agents metformin and glyburide as well as insulin. We also review the evidence for the safety and efficacy of these medications in pregnancy.

Evidence Acquisition

Articles were obtained from PubMed, the ACOG Practice Bulletin on Gestational Diabetes Mellitus, and the SMFM statement on the pharmacological treatment of gestational diabetes.

Results

Insulin does not cross the placenta and has an established safety profile in pregnancy and is therefore considered a first-line treatment for gestational diabetes. Metformin and glyburide have also been shown to be relatively safe in pregnancy but with more limited long-term data. Regarding maternal and fetal outcomes, metformin is superior to glyburide and similar to insulin.

Conclusions and Relevance

Insulin is the preferred pharmacologic treatment according to ACOG. However, SMFM has stated that outcomes with metformin are similar, and it may also be considered as first-line therapy. Both agree that the available data show that metformin is safer and superior to glyburide, and glyburide is no longer recommended as a first-line therapy for the treatment of gestational diabetes.

Pharmacotherapy for hyperglycemia in pregnancy - The new insulins

Hyperglycemia in pregnancy may lead to adverse maternal, fetal and neonatal outcomes. Tight glycemic control is prudent in order to reduce pregnancy complications. For many years, the gold standard pharmacological therapy during pregnancy was human insulin. Recently, insulin analogues were also introduced to clinical use in pregnancy. This brief review aims to summarize the information on the efficacy and safety of insulin analogue therapy during gestation. The strengths and pitfalls of insulin analogue administration during gestation, compared with human insulin, are presented. According to studies in pregnant women with type 1 diabetes, insulins lispro, aspart and detemir are efficacious and safe. Correspondingly, the FDA has reclassified them for the treatment of pregnant women with diabetes from category C to category B. Although large and prospective data on insulin glargine in gestation are still lacking, no major safety concerns were documented. No controlled trials with insulins glulisine and degludec were conducted in pregnancy. In sum, insulin analogues are practical therapeutic options for hyperglycemia in pregnancy, mainly due to their hypoglycemia risk reduction. More research for their use in pregnant women with gestational diabetes or type 2 diabetes should be conducted. Overall, their efficacy and safety is possibly comparable to human insulin.

The care of pregestational and gestational diabetes and drug metabolism considerations

INTRODUCTION

Normal pregnancy development involves gradual decline in insulin sensitivity, which sometimes requires pharmacotherapy. Insulin is the drug of choice for gestational and pregestational diabetes. Metabolism of traditional insulins results in inadequate onset and duration of action and marked peak activity. These properties increase risk of excessive glucose excursions, which are especially undesirable during pregnancy. Insulin analogs have been emerging as a safer and more effective treatment of diabetes during pregnancy. Areas covered: This manuscript reviews currently used antihyperglycemic agents: fast and long-acting insulins, metformin and glyburide. Trials demonstrating their efficacy and safety during pregnancy are described. Certain drug metabolism considerations (e.g. affinity to IGF-1) are emphasized. Expert opinion: The theories that insulin analogs bind to immunoglobulin and cross placenta have been disproved. Lispro, aspart, glargine and detemir do not transfer across the placenta and do not result in adverse maternal and neonatal outcomes. In addition, favorable pharmacokinetic profiles (rapid onset and 24-hour near peakless activity) substantially reduce blood glucose variability including hypoglycemia. We believe that insulin analogs should be given strong consideration for the treatment of diabetes during pregnancy. Metformin has also proven to be safe and may be considered as an initial single agent for milder gestational diabetes.

Effects of maternal hypoglycemia on fetal eye and skeleton development in rats

The relationship between insulin-induced maternal hypoglycemia and teratogenicity was investigated in detail. We injected 4 different forms of insulin (insulin human, aspart, glargine, and detemir) subcutaneously at 1 or 2 dose levels to Sprague-Dawley rats from Days 6 to 11 of pregnancy, measured blood glucose levels, and conducted fetal examination. In the insulin human and aspart (low dose) groups, while severe hypoglycemia (approximately 50mg/dL) was seen, it lasted only 6h and no fetal anomalies were observed. Fetal axial skeleton anomalies were observed in the aspart (high dose) group, which exhibited intermediate-duration of severe hypoglycemia (9h). Eye and axial skeleton anomalies were observed in the glargine and detemir groups, which exhibited continuous severe hypoglycemia (≥9h). These results revealed that insulin-induced maternal hypoglycemia caused fetal eye and skeleton anomalies and the causative key factors were duration of maternal severe hypoglycemia.

Use of Insulin Lispro Protamine Suspension in Pregnancy

Maternal metabolism changes substantially during pregnancy, which poses numerous challenges to physicians managing pregnancy in women with diabetes. Insulin is the agent of choice for glycemic control in pregnant women with diabetes, and the insulin analogs are particularly interesting for use in pregnancy. These agents may reduce the risk of hypoglycemia and promote a more physiological glycemic profile than regular human insulin in pregnant women with type 1 (T1D), type 2 (T2D), or gestational (GDM) diabetes. However, there have been concerns regarding potential risk for crossing the placental barrier, mitogenic stimulation, teratogenicity, and embryotoxicity. Insulin lispro protamine suspension (ILPS), an intermediate- to long-acting insulin, has a stable and predictable pharmacological profile, and appears to have a favorable time–action profile and produce desirable basal and postprandial glycemic control. As the binding of insulin lispro is unaffected by the protamine molecule, ILPS is likely to have the same mitogenic and immunogenic potential as insulin lispro. Insulin lispro produces similar outcomes to regular insulin in pregnant women with T1D, T2D, or GDM, does not cross the placental barrier, and is considered a useful treatment option for pregnant women with diabetes. Clinical data support the usefulness of ILPS for basal insulin coverage in non-pregnant patients with T1D or T2D, and suggest that the optimal regimen, in terms of balance between efficacy and hypoglycemic risk, is a once-daily injection, especially in patients with T2D. Available data concerning use of ILPS in pregnant women are currently derived from retrospective analyses that involved, in total, >1200 pregnant women. These analyses suggest that ILPS is at least as safe and effective as neutral protamine Hagedorn insulin. Thus, available experimental and clinical data suggest that ILPS once daily is a safe and effective option for the management of diabetes in pregnant women.

Funding: Eli Lilly and Company.

Safety considerations with pharmacological treatment of gestational diabetes mellitus

The number of women with gestational diabetes mellitus (GDM: diabetes first diagnosed in pregnancy) continues to grow, as do the associated risks of antenatal and postnatal complications and the chance of future diabetes and obesity in both mother and offspring. Recent randomised controlled trials have demonstrated clear benefits for intensive management of GDM using lifestyle modification, self blood glucose monitoring, close clinical supervision and, where glycaemia remains inadequately controlled, insulin therapy. More recently, metformin and glibenclamide have been shown to adequately reduce hyperglycaemia as part of a stepped approach to GDM management, with a switch to insulin therapy where necessary. Other oral medications have not been shown to be safe in pregnancy. Human insulin therapy is safe within the limits of hypoglycaemia and weight gain. Most insulin analogues are also now considered safe for use in pregnancy (insulin lispro, aspart and detemir). Metformin therapy is oral, and therefore preferred to insulin, but is associated with more gastrointestinal adverse effects, although not hypoglycaemia or weight gain. Conversely, glibenclamide is also an oral therapy but is associated with hypoglycaemia and weight gain. However, metformin crosses the placenta and it remains unclear whether glibenclamide crosses the placenta or not: long-term risks have not been shown, and are thought to be minimal, but further studies are needed. Metformin is seen by some as the treatment of choice where weight gain is an issue, providing that the unanswered questions over the long-term safety of oral agents have been discussed.

Prescribing of antidiabetic therapies in Ireland: 10-year trends 2003-2012

BACKGROUND

Over the last decade there have been significant changes in the prescribing of antidiabetic therapies. It is of interest to know about these trends and variations in the Irish population so that future prescribing patterns can be estimated.

AIMS

To examine the trends in prescribed antidiabetic treatments, including variations across age, gender, socioeconomic status and regions in the Irish population over the last 10 years.

METHODS

The Irish national pharmacy claims database was used to identify patients ≥ 16 years dispensed antidiabetic agents (oral or insulin) from January 2003 to December 2012 through the two main community drug schemes for diabetes. The rate of prescribing per 1,000 population was calculated. Logistic regression was used to examine variations in prescribing in patients with diabetes.

RESULTS

There was a significant increase in the prescribing of fast and long-acting insulin analogues with a rapid decline in the prescribing of human insulin (p < 0.0001). Increased prescribing of metformin, incretin modulators and fixed oral combination agents was observed (p < 0.0001). Females and older aged patients were more likely to be prescribed human insulin than other insulins. Metformin was less likely while sulphonylureas were more likely to be prescribed in older than younger aged patients. Socioeconomic differences were observed in increased prescribing of the newer and more expensive antidiabetic agents in the non-means tested scheme. Regional variations were observed in the prescribing of both insulin and oral antidiabetic agents.

CONCLUSION

There has been an increase over time in the prescribing of both insulin and oral antidiabetic agents in the Irish population with increasing uptake of newer antidiabetic agents. This has implications for projecting future uptake and expenditure of these agents given the rising level of diabetes in the population.

[Gestational diabetes: diagnosis, short and long term management]

Universal consensus on the diagnosis methods and thresholds has long been lacking. The recently published Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study has been used to confirm the link between hyperglycemia and materno-fetal complications. Consequently, in France, the Société francophone du diabète (SFD) and the Collège national des gynécologues et obstétriciens français (CNGOF) proposed an expert consensus on gestational diabetes mellitus for clinical practice. Fasting blood glucose should be measured at the first visit during early pregnancy for women with risk factors to identify the women with pregestational diabetes. It is proposed a selective screening on risk factors rather than universal screening. Specific treatment of gestational diabetes reduced materno-fetal complications compared to the absence of therapy. Women with a history of gestational diabetes mellitus are characterized by a high risk of type 2 diabetes mellitus.

Future of newer basal insulin

Basal insulin have been developed over the years. In recent times newer analogues have been added to the armanentarium for diabetes therapy. This review specifically reviews the current status of different basal insulins.

Long-acting basal insulin analogs: latest developments and clinical usefulness

All patients with type 1 diabetes mellitus need insulin treatment permanently, and many patients with type 2 diabetes will require insulin therapy. Basal insulin analogs are increasingly used in the treatment of diabetes, with the aim of offering a better replication of the pattern of basal endogenous secretion of insulin. Their flatter pharmacodynamic profile, with a much lower peak of action, their slow and continuous absorption into the systemic circulation, and prolonged duration, more closely duplicate the endogenous insulin secretion leading to physiological basal glycemic control and affording more flexible treatment with fewer hypoglycemia episodes. The basal analogs represent the most significant advances in 'basal insulin' supplementation, and can be used in different insulin regimens achieving the same clinical effectiveness over conventional insulins, with benefits in terms of hypoglycemia and less weight gain, and may be an option for patients with problematic hypoglycemia despite optimization of conventional insulin therapy. At present, there are no data on micro- or macrovascular endpoints, and indeed it is unlikely that these will become available, at least in the foreseeable future. The evidence for basal insulin analogs affecting the risk of cancer is limited, and overriding diabetes indications rather than putative cancer concerns should remain the principal consideration when selecting therapy in patients with diabetes.

Insulins: past, present, and future

This article highlights selected milestones in insulin discovery and its continued development as a pivotal therapy for diabetes. The last 90 years have witnessed tremendous progress in insulin therapy, from the initial crude, yet life-saving, animal insulin extracts to novel human insulin analogues. Although the complete physiologic replacement of insulin is inherently difficult to achieve with open-loop subcutaneously administered insulin, the continued development of improved injectable insulin formulations with superior pharmacokinetics and pharmacodynamics will enhance glucose control, and represents important clinical advances in the treatment of both type 1 and type 2 diabetes.

Contraception, and pregnancy in adolescents with type 1 diabetes: a review

Adolescence is a critical period for girls with type 1 diabetes mellitus (T1D). Reproductive issues, such as menstrual abnormalities, risk of an unplanned pregnancy, and contraception, should be addressed during this phase of life. This paper reviews several reproductive issues that are important in the care of adolescents, including pubertal development, menstrual abnormalities, ovulatory function, reproductive problems, the effects of hyperglycemia, contraception, and treatment of an unplanned pregnancy. A review of the literature was conducted. A MEDLINE search January 1966 to March 2011 was performed using the following MESH terms: puberty, menarche, ovary, polycystic ovary syndrome, menstruation, contraception, contraception-barrier, contraceptives-oral-hormonal, sex education, family planning services, and pregnancy in adolescence. This literature search was cross-referenced with an additional search on diabetes mellitus-type 1, diabetes complications, and pregnancy in diabetes. All published studies were searched regardless of the language of origin. Bibliographies were reviewed to extract additional relevant sources.

Managing diabetes during pregnancy with insulin lispro: a safe alternative to human insulin

OBJECTIVE

To assess the safety of the use of insulin lispro during pregnancy on the basis of published literature and to report on any related efficacy findings.

METHODS

The National Center for Biotechnology Information Entrez Database PubMed (http://www.ncbi. nlm.nih.gov/pubmed/) was used to search for citations from MEDLINE in the November 2009 time frame that contained safety data and efficacy results on the use of insulin lispro during pregnancy.

RESULTS

From the MEDLINE search, we identified a total of 27 publications (with 1,265 pregnancies) with relevant information, which were included in this report. No statistically significant differences in the rates of occurrence of congenital anomalies or spontaneous abortions associated with the use of insulin lispro during pregnancy, in comparison with the use of human insulin, were reported. Moreover, in comparison with human insulin, insulin lispro was reported to result in improved glycemic control, as demonstrated by lower postprandial glucose concentrations and hemoglobin A1c levels.

CONCLUSION

The current review of the published literature indicates that insulin lispro is a safe alternative to human insulin with similar perinatal outcomes and potentially improved glycemic control in the management of diabetes during pregnancy.

Closed-loop insulin delivery during pregnancy complicated by type 1 diabetes

OBJECTIVE

This study evaluated closed-loop insulin delivery with a model predictive control (MPC) algorithm during early (12-16 weeks) and late gestation (28-32 weeks) in pregnant women with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Ten women with type 1 diabetes (age 31 years, diabetes duration 19 years, BMI 24.1 kg/m(2), booking A1C 6.9%) were studied over 24 h during early (14.8 weeks) and late pregnancy (28.0 weeks). A nurse adjusted the basal insulin infusion rate from continuous glucose measurements (CGM), fed into the MPC algorithm every 15 min. Mean glucose and time spent in target (63-140 mg/dL), hyperglycemic (>140 to ≥ 180 mg/dL), and hypoglycemic (<63 to ≤ 50 mg/dL) were calculated using plasma and sensor glucose measurements. Linear mixed-effects models were used to compare glucose control during early and late gestation.

RESULTS

During closed-loop insulin delivery, median (interquartile range) plasma glucose levels were 117 (100.8-154.8) mg/dL in early and 126 (109.8-140.4) mg/dL in late gestation (P = 0.72). The overnight mean (interquartile range) plasma glucose time in target was 84% (50-100%) in early and 100% (94-100%) in late pregnancy (P = 0.09). Overnight mean (interquartile range) time spent hyperglycemic (>140 mg/dL) was 7% (0-40%) in early and 0% (0-6%) in late pregnancy (P = 0.25) and hypoglycemic (<63 mg/dL) was 0% (0-3%) and 0% (0-0%), respectively (P = 0.18). Postprandial glucose control, glucose variability, insulin infusion rates, and CGM sensor accuracy were no different in early or late pregnancy.

CONCLUSIONS

MPC algorithm performance was maintained throughout pregnancy, suggesting that overnight closed-loop insulin delivery could be used safely during pregnancy. More work is needed to achieve optimal postprandial glucose control.

Placental transfer of the insulin analog glargine in the ex vivo perfused placental cotyledon model

OBJECTIVE

The aim was to characterize the transfer of the insulin analog glargine across the placenta using the placental perfusion model.

METHODS

Placentas were obtained and selected cotyledons were cannulated and dually perfused. Glargine, 50 mU/L (n = 2) and 200 mU/L (n = 1), and a reference marker, antipyrine (50 μg/mL), were added to the maternal circulation. Samples were taken from the maternal and fetal compartments.

RESULTS

Glargine was not detected in the fetal compartment. In the maternal compartment, the steady state concentration was 50% lower than the starting concentration.

CONCLUSIONS

Glargine probably does not cross the human placenta. Reduced maternal steady state concentrations may suggest insulin uptake by the placenta.

Pregnancy complicated by diabetes: what is the best level of HbA1c for conception?

To reduce the congenital malformations that occur in pregnancies complicated by diabetes, it is essential to achieve and maintain a good metabolic control before conception. In this context, measuring HbA1c is considered as the gold standard for monitoring metabolic control in diabetes and various different HbA1c levels have been recommended as optimal in the preconception period for diabetic women planning a pregnancy. An analysis of key studies published on this issue until now clearly shows that HbA1c levels correlate closely with the occurrence of congenital malformations and other neonatal complications characteristic of pregnant diabetic women. HbA1c is therefore one of the key markers to use in monitoring metabolic control, and the most reasonable approach would seem to be to use a standardized measurement method and aim for HbA1c levels resembling normal values as closely as possible, with a view to preventing episodes of hypoglycemia.

Approach to the patient with diabetes during pregnancy

The epidemics of obesity and type 2 diabetes mellitus (T2DM) globally are paralleling an increase in the number of women with T2DM becoming pregnant. Because T2DM is frequently undiagnosed before pregnancy, the risk of major malformations in the developing fetus is increased due to uncontrolled hyperglycemia. The lack of preconception care and the increase in complications of pregnancy due to the coexistence of obesity and T2DM are of concern from both an individual and a public health standpoint. Rapid achievement of normoglycemia with limited weight gain is critical to optimize maternal and fetal outcomes in all women with diabetes during pregnancy, regardless of the type of diabetes. This article will focus on T2DM preceding pregnancy due to its increasing prevalence and potentially dire fetal and maternal consequences. Euglycemia before, during, and after all pregnancies complicated by diabetes results in the best opportunity for optimal outcomes for mother and infant.

An update on the treatment of type 1 and type 2 diabetes mellitus: focus on insulin detemir, a long-acting human insulin analog

Basal insulin analogs are used to minimize unpredictable processes of NPH insulin. Modification of the human insulin molecule results in a slower distribution to peripheral target tissues, a longer duration of action with stable concentrations and thus a lower rate of hypoglycemia. Insulin detemir is a basal insulin analog that provides effective therapeutic options for patients with type 1 and type 2 diabetes. For glycemic control, no significant differences were found in HbA_1c levels compared with NPH and insulin glargine. It is comparable with insulin glargine in significantly reducing rates of all types of hypoglycemia. Clinical studies have demonstrated that detemir is responsible for significantly lower within-subject variability and no or less weight gain than NPH insulin and glargine. Recent pharmacodynamic studies have shown that detemir can be used once daily in many patients with diabetes. Together with patient-friendly injection devices and dose adjustments, it provides a treatment option with the potential to lower the key barriers of adherence to insulin therapy in type 2 diabetes. Recent guidelines for treatment of type 2 diabetes suggest starting intensive therapy of hyperglycemia at an early stage of diabetes and recommend therapeutic options that provide the possibility of reaching HbA_1c goals individually, with a low risk of hypoglycemia or other adverse effects of treatment. The properties of insulin detemir match these requirements.