Does Metformin improve reproduction outcomes for non-obese, infertile women with polycystic ovary syndrome? Meta-analysis and systematic review

Effectiveness of metformin to pregnant women with PCOS to reduce spontaneous abortion and gestational diabetes mellitus: a protocol for an overview of reviews

INTRODUCTION

Polycystic ovary syndrome (PCOS) is a globally prevalent endocrinological disorder and has been associated with poor pregnancy outcomes, including a higher rate of gestational diabetes and miscarriage. Metformin is among the drugs investigated to improve the prognosis of pregnant women with PCOS.

OBJECTIVE

To conduct an overview of systematic reviews examining the effects of metformin versus placebo or no intervention throughout pregnancy among pregnant women with a preconception PCOS diagnosis to reduce the incidence of miscarriage and gestational diabetes.

METHODS AND ANALYSIS

We will perform an overview of systematic reviews by searching Embase, PubMed, Virtual Health Library, Cochrane Central Register of Controlled Trials, Trip Database, Scopus, Web of Science and Cumulative Index to Nursing and Allied Health Literature from inception to 17 August 2023. Language, publication status and year indexed or published filters will not be applied. Two reviewers will independently screen and select papers, assess their quality, evaluate their risk of bias and collect the data. The included reviews will be summarised narratively. The quality and risk of bias of the systematic review and meta-analysis studies included will be assessed using AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews, Second Version) and ROBIS (Risk of Bias in Systematic Reviews), respectively.

ETHICS AND DISSEMINATION

This overview of reviews will analyse data from systematic reviews on the use of metformin for prepregnancy diagnosis of PCOS to reduce adverse outcomes. As there will be no primary data collection, a formal ethical analysis is unnecessary. The study outcomes will be submitted to a peer-reviewed journal and presented at conferences.

PROSPERO REGISTRATION NUMBER

CRD42023441488.

The effect of β-cell dysfunction on reproductive outcomes of PCOS undergoing IVF or ICSI embryo transfer cycles: a retrospective cohort study

Objective

To investigate the effects of β-cell dysfunction on IVF outcomes in women with PCOS.

Methods

This retrospective cohort study includes 1,212 women with PCOS undergoing their first IVF cycle between September 2010 and December 2019. Beta-cell dysfunction was measured by homeostasis model assessment of β-cell function (HOMA-β) index.

Results

In quartiles of HOMA-β, the incidence of miscarriage dramatically increased from 10.2% (Q1) to 31.1% (Q4) (P for trend <0.001). Likewise, the incidence of miscarriage in quartiles of HOMA-β also showed a similar trend (P for trend <0.001). After adjusting for confounding factors, logistic regression analyses showed that high HOMA-IR values were independently associated with a high risk of miscarriage, with the odds ratios (OR) and 95% confidence intervals for quartiles 2-4 versus quartile 1 were 1.30 (0.69-2.46), 1.82 (0.97-3.43), and 3.57 (1.86-6.85), respectively (P for trend <0.001). When analyzed jointly, women in the highest HOMA-IR and highest HOMA-β group exhibited the highest risk for miscarriage compared with all other groups. Furthermore, higher HOMA-IR values were associated with higher risks of miscarriage among PCOS women regardless of HOMA-β values.

Conclusions

β-cell dysfunction is independently associated with increased miscarriage rate and decreased live birth rate in women with PCOS. It also plays a synergistic role with IR in terms of the reproductive outcomes, while the influence of IR overweighs that of β-cell dysfunction.

Insulin-sensitizing agents for infertility treatment in woman with polycystic ovary syndrome: a narrative review of current clinical practice

PURPOSE

Polycystic ovary syndrome (PCOS) is an endocrine, metabolic, and reproductive disorder which, according to the Rotterdam criteria, affects up to 24% of women of childbearing age. Although the prevalence of infertility in this subpopulation of women is high, the optimal treatment has not been fully established yet. Insulin resistance is considered to be an important mechanism involved in the development of PCOS; hence, the aim of this narrative review is to present an overview of the current pharmacological insulin-sensitizing treatment modalities for infertile women with PCOS.

METHODS

A MEDLINE and PubMed search for the years 1990-2023 was performed using a combination of keywords. Clinical trials with insulin sensitizers used for infertility treatment as well as analyses of systematic reviews and meta-analyses were evaluated. When deemed necessary, additional articles referenced in the retrieved papers were included in this narrative review.

RESULTS

Several insulin-sensitizing compounds and various therapeutical protocols are available for infertility treatment of women with PCOS. Metformin is the most common adjuvant medication to induce ovulation in infertile women with PCOS and is more frequently administered in combination with clomiphene citrate than on its own. Recently, inositol and glucagon-like peptide-1 (GLP-1) receptor agonists have emerged as possible options for infertility treatment in PCOS.

CONCLUSION

The future of medical treatment of PCOS women with infertility lies in a personalized pharmacological approach, which involves various compounds with different mechanisms of action that could modify ovarian function and endometrial receptivity, ultimately leading to better overall reproductive outcomes in these women.

Effect of Metformin (MTF) Intervention During Pregnancy in Women With Polycystic Ovarian Syndrome (PCOS): A Systematic Review

Metformin (MTF) is a commonly prescribed medication for women with polycystic ovarian syndrome (PCOS), but its impact on pregnancy outcomes in women with PCOS remains controversial. This systematic review aims to evaluate the effects of MTF intervention on pregnancy outcomes in women with PCOS and the impact of MTF on offspring. A comprehensive search is conducted in PubMed, Google Scholar, and ScienceDirect databases from 2019 up to May 16, 2023. Only review articles and meta-analyses are included, focusing on women with PCOS who received MTF during pregnancy or as part of infertility treatment. The primary outcomes of interest are clinical pregnancy rate (CPR), miscarriage rate, preterm birth rate, and live birth rate. Secondary outcomes are the safety profile of MTF. Data extraction and quality assessment are performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the assessment using the multiple systematic reviews (AMSTAR) 2 tool, respectively. The initial search produced 1877 studies. Thirteen studies were included in the review. While the use of MTF during pregnancy in women with PCOS may have some benefits in reducing certain pregnancy complications such as pregnancy-induced hypertension (PIH), gestational diabetes mellitus (GDM), preeclampsia, preterm delivery, reducing the risk of ovarian hyperstimulation syndrome (OHSS) in women with PCOS undergoing in vitro fertilization (IVF); however, there is no significant difference in clinical pregnancy and live birth rates overall, but subgroup analysis suggests potential benefits for women with a higher body mass index (BMI). MTF is associated with a larger fetal head circumference and potential long-term effects on offspring's BMI and obesity. Further research is needed to better understand the optimal dosing of MTF, long-term effects, and effects in specific subgroups. The heterogeneity of the included studies limited the ability to analyze the data effectively, leading to challenges in drawing definitive conclusions.

Interventions to prevent or reduce the incidence and severity of ovarian hyperstimulation syndrome: a systematic umbrella review of the best clinical evidence

Ovarian hyperstimulation syndrome (OHSS) is a potentially life-threating iatrogenic complication of the early luteal phase and/or early pregnancy after in vitro fertilization (IVF) treatment. The aim of the current study was to identify the most effective methods for preventing of and reducing the incidence and severity of OHSS in IVF patients. A systematic review of systematic reviews of randomized controlled trials (RCTs) with meta-analysis was used to assess each potential intervention (PROSPERO website, CRD 268626) and only studies with the highest quality were included in the qualitative analysis. Primary outcomes included prevention and reduction of OHSS incidence and severity. Secondary outcomes were maternal death, incidence of hospital admission, days of hospitalization, and reproductive outcomes, such as incidence of live-births, clinical pregnancies, pregnancy rate, ongoing pregnancy, miscarriages, and oocytes retrieved. A total of specific interventions related to OHSS were analyzed in 28 systematic reviews of RCTs with meta-analyses. The quality assessment of the included studies was high, moderate, and low for 23, 2, and 3 studies, respectively. The certainty of evidence (CoE) for interventions was reported for 37 specific situations/populations and resulted high, moderate, and low-to-very low for one, 5, and 26 cases, respectively, while it was not reported in 5 cases. Considering the effective interventions without deleterious reproductive effects, GnRH-ant co-treatment (36 RCTs; OR 0.61, 95% C 0.51 to 0.72, n = 7,944; I² = 31%) and GnRH agonist triggering (8 RCTs; OR 0.15, 95% CI 0.05 to 0.47, n = 989; I² = 42%) emerged as the most effective interventions for preventing OHSS with a moderate CoE, even though elective embryo cryopreservation exhibited a low CoE. Furthermore, the use of mild ovarian stimulation (9 RCTs; RR 0.26, CI 0.14 to 0.49, n = 1,925; I² = 0%), and dopaminergic agonists (10 RCTs; OR 0.32, 95% CI 0.23 to 0.44, n = 1,202; I² = 13%) coadministration proved effective and safe with a moderate CoE. In conclusion, the current study demonstrates that only a few interventions currently can be considered effective to reduce the incidence of OHSS and its severity with high/moderate CoE despite the numerous published studies on the topic. Further well-designed RCTs are needed, particularly for GnRH-a down-regulated IVF cycles.

Influence of metformin on hyperandrogenism in women with polycystic ovary syndrome: a systematic review and meta-analysis of randomized clinical trials

PURPOSE

To summarize the effects of metformin treatment on markers of hyperandrogenism in patients diagnosed with polycystic ovary syndrome (PCOS).

METHODS

A systematic review, with meta-analysis, of randomized placebo-controlled clinical trials that evaluated the effects of metformin treatment in adult patients with PCOS on the levels of hyperandrogenism markers was conducted. The literature search, data extraction, risk of bias, and the assessment of certainty of evidence were performed independently by two reviewers using a structured form. The results were combined by applying the random effect, and the effect measure presented as a standardized mean difference (SMD). Significant values were considered as p < 0.05 with 95% CI. Furthermore, sensitivity analyses were performed in order to explore possible heterogeneity between studies.

RESULTS

Were included 18 studies in the quantitative evaluation and 17 studies (23 reports) in the quantitative evaluation. A significant reduction in total testosterone levels was seen in the metformin-treated group when compared to the control group after combining the results by the sensitivity analysis [SMD: - 0.46 (95% CI: - 0.89 to - 0.02)]. Therefore, FAI values were also regulated by metformin treatment.

CONCLUSION

We showed that metformin proved to be effective in reducing total testosterone levels, and the same was observed for free androgen index (FAI) values-a measure influenced by testosterone levels. The protocol of this study was registered at Prospero (CRD42021235761).

The Effectiveness and Safety of Exenatide Versus Metformin in Patients with Polycystic Ovary Syndrome: A Meta-Analysis of Randomized Controlled Trials

Polycystic ovary syndrome (PCOS) is an endocrine disorder that affects women of childbearing age, resulting in reproductive dysfunction, hyperinsulinemia, and obesity. While several drugs are currently approved for use in these patients, their relative effectiveness remains controversial. The purpose of this meta-analysis was to evaluate the reproductive efficacy and safety of exenatide, a glucagon-like peptide-1 receptor agonist, versus metformin, an insulin sensitizer, in the treatment of patients with PCOS. Nine randomized controlled trials (RCTs) were included, comprising 785 PCOS patients, of whom 385 received exenatide and 400 received metformin. Compared with metformin, exenatide was significantly more effective in treating these patients, as demonstrated by increased pregnancy rate (relative risk (RR) = 1.93, 95% confidence interval (CI) 1.28 to 2.92, P = 0.002), greater ovulation rate (RR = 1.41, 95% CI 1.11 to 1.80, P = 0.004), decreased body mass index (mean difference =  − 1.72 kg/m2, 95% CI − 2.27 to − 1.18, P = 0.00001), and improved insulin resistance (standard mean difference =  − 0.62, 95% CI − 0.91 to − 0.33, P < 0.0001). There was no significant difference in the occurrence of adverse events (gastrointestinal reactions, hypoglycemia, etc.) between the two therapies. However, given the moderate to high quality and possible bias of the included studies, the available evidence is inconclusive. More high-quality studies are needed to assess the effects of exenatide in order to provide stronger evidence for its use in this patient population.

The Potential of SGLT-2 Inhibitors in the Treatment of Polycystic Ovary Syndrome: The Current Status and Future Perspectives

Polycystic ovary syndrome (PCOS) is the most frequent endocrinopathy during women’s reproductive age. PCOS is a heterogeneous disorder featuring specific cardiometabolic properties. The association between the presence of metabolic disorders and PCOS supports the claim that the regulation of glycemic status is very important in these patients. There is a wide range of therapeutic options (including those treating diabetes mellitus type 2) with potential advantages available for the management of PCOS. Sodium–glucose cotransporter type 2 inhibitors (SGLT-2is) improve glucose metabolism, reduce fat tissue, lower blood pressure, reduce oxidative stress and inflammation, and protect the cardiovascular system. Currently, the use of SGLT-2is is not widespread in PCOS therapy, although these drugs represent a promising new therapeutic approach. Therefore, it is necessary to initiate further study in order to determine more effective therapies for PCOS and investigate the effect of SGLT-2is, both as a monotherapy and in combination with other drugs. It is necessary to understand the mechanisms underlying SGLT-2is in PCOS and their effects on long-term complications, especially since the gold standard treatment for PCOS, such as metformin and oral contraceptives, do not have long-term cardioprotective effects. The effects of SGLT-2is seem to involve cardiac protection, while diminishing endocrine and reproductive abnormalities in PCOS. In the current narrative review, we examine the most recent clinical evidence and discuss the potential applications of SGLT-2is for PCOS therapy.

Glucose-lowering drugs with cardiovascular benefits as modifiers of critical elements of the human life history

The life history theory assumes that all organisms are under selective pressure to harvest external resources and allocate them to maximise fitness: only organisms making the best use of energy obtain the greatest fitness benefits. The trade-off of energy spans four functions: maintenance, growth, reproduction, and defence against pathogens. The innovative antihyperglycaemic agents glucagon-like peptide 1 (GLP-1) receptor agonists and sodium-glucose cotransporter 2 (SGLT2) inhibitors decrease bodyweight and have the potential to counter low-grade inflammation. These key activities could rewire two components of the life history theory operative in adulthood-ie, maintenance and defence. In this Personal View, we postulate that the benefits of these medications on the cardiovascular system, beyond their glucose-lowering effects, could be mediated by the reduction of the maintenance cost driven by obesity and efforts spent on blunting low-grade inflammation.

Metformin Treatment Modulates Long Non-Coding RNA Isoforms Expression in Human Cells

Long noncoding RNAs (lncRNAs) undergo splicing and have multiple transcribed isoforms. Nevertheless, for lncRNAs, as well as for mRNA, measurements of expression are routinely performed only at the gene level. Metformin is the first-line oral therapy for type 2 diabetes mellitus and other metabolic diseases. However, its mechanism of action remains not thoroughly explained. Transcriptomic analyses using metformin in different cell types reveal that only protein-coding genes are considered. We aimed to characterize lncRNA isoforms that were differentially affected by metformin treatment on multiple human cell types (three cancer, two non-cancer) and to provide insights into the lncRNA regulation by this drug. We selected six series to perform a differential expression (DE) isoform analysis. We also inferred the biological roles for lncRNA DE isoforms using in silico tools. We found the same isoform of an lncRNA (AC016831.6-205) highly expressed in all six metformin series, which has a second exon putatively coding for a peptide with relevance to the drug action. Moreover, the other two lncRNA isoforms (ZBED5-AS1-207 and AC125807.2-201) may also behave as cis-regulatory elements to the expression of transcripts in their vicinity. Our results strongly reinforce the importance of considering DE isoforms of lncRNA for understanding metformin mechanisms at the molecular level.

Distinctions in PCOS Induced by Letrozole Vs Dehydroepiandrosterone With High-fat Diet in Mouse Model

Polycystic ovarian syndrome (PCOS) is a complex health condition associated with metabolic disturbances and infertility. Recent data suggest that the prevalence of PCOS is increasing among women globally, although the etiology of these trends is undefined. Consequently, preclinical models that better reflect the biology of PCOS are urgently needed to facilitate research that can lead to the discovery of prevention strategies or improved management. The existing animal models have several limitations as they do not reflect all the PCOS features metabolically and/or phenotypically. Therefore, there is no clear consensus on the use of appropriate animal model and selection of the most appropriate PCOS-inducing agent. To that end, we have established a Swiss albino mouse model of PCOS based on 3 weeks of daily treatment with letrozole (50 μg/day; intraperitoneal) and dehydroepiandrosterone (DHEA, 6 mg/100 g body weight; subcutaneous) in 5-week-old female mice fed on normal or high-fat diet (HFD). Mice were regularly assessed for body weight, blood glucose, and estrous cycle. Three weeks after drug administration, mice were sacrificed and assessed for blood-based metabolic parameters as well as ovarian function. Our results indicate that DHEA combined with HFD produces changes mimicking those of clinical PCOS, including elevated serum testosterone and luteinizing hormone, dyslipidemia, poor ovarian microenvironment, and development of multiple ovarian cysts, recapitulating cardinal features of PCOS. In comparison, normal diet and/or letrozole produced fewer features of PCOS. The data from the experimental models presented here can improve our understanding of PCOS, a growing concern in women's health.

Metformin Protects Cardiovascular Health in People With Diabetes

Background

Metformin is the most commonly used drug for patients with diabetes, but there is still some controversy about whether it has a protective effect on cardiovascular health. We therefore used the National Health and Nutritional Examination Survey (NHANES) database to analyze the impact of metformin use on cardiovascular health in patients with diabetes.

Methods

We extracted the demographic data and laboratory test results of all people with diabetes in the NHANES database from January 2017 to March 2020. The outcomes were seven indicators of cardiovascular health from the American Heart Association, each was scored as 0, 1, and 2 to represent poor, moderate, and ideal health statuses, respectively. The scores for the indicators (excluding diet and glycemic status) were summed, and the sum score was then considered to indicate unhealthy (0–5) or healthy (>5). Multivariate logistic regression analysis was used, and subgroup analyses were performed by age, alcohol consumption, education, and marital status.

Results

This study included 1,356 patients with diabetes, among which 606 were taking metformin. After adjusting for all included variables, oral metformin in patients with diabetes had a protective effect on the cardiovascular health of patients (OR = 0.724, 95% CI = 0.573–0.913, P = 0.007). Subgroup analysis indicated that metformin protects the cardiovascular health of people with diabetes more clearly in those who are young (OR = 0.655, 95% CI = 0.481–0.892, P = 0.007), married (OR = 0.633, 95% CI = 0.463–0.863, P = 0.003), and drink alcohol (OR = 0.742, 95% CI = 0.581–0.946, P = 0.016).

Conclusion

This study found that metformin has a protective effect on the cardiovascular health of patients with diabetes. The study findings support the general applicability of metformin.